Single-crystalline Pd nanocrystals enclosed by {111} or {100} facets with controllable sizes were synthesized and originally employed as catalysts in the aerobic oxidation of 5-hydroxymethyl-2-furfural (HMF). The experimental results indicated that the particle size and exposed facet of Pd nanocrystals could obviously influence their catalytic performance. The size-dependent effect of Pd nanocrystals in this reaction could only be derived from the different Pd dispersions. Therefore, the facet effect of Pd nanocrystals was first investigated in this work through experimental and theoretical approaches. It was found that Pd-NOs enclosed by {111} facets were more efficient than Pd-NCs enclosed by {100} facets for the aerobic oxidation of HMF, especially for the oxidation step from 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) toward 5-formyl-2-furancarboxylic acid (FFCA). The TOF value of Pd-NOs(6 nm) was 2.6 times as high as that of Pd-NCs(7 nm) and 5.2 times higher than that of commercial Pd/C catalyst for HMF oxidation. Through density functional theory (DFT) calculations, the notably enhanced catalytic performance of Pd-NOs could be mainly attributed to the lower energy barrier in the alcohol oxidation step (from HMFCA to FFCA) and higher selectivity for O2 hydrogenation to produce peroxide.Keywords: 5-hydroxymethyl-2-furfural; aerobic oxidation; facet effect; single-crystalline Pd; size-dependent effect;

AbstractThe three-dimensionally ordered macroporous alumina-carbon composite materials were firstly prepared through a surfactant-assisted colloidal crystal template method and applied to support Pt nanoparticles. The results of SEM, XRD, TEM, and N2 sorption analyses revealed that these composite materials possessed highly ordered macroporous structures with meso- and micropores within the skeletons of macropores and that the Pt nanoparticles were well dispersed on these materials with a very narrow size distribution. These prepared Pt nanocatalysts were evaluated in the asymmetric hydrogenation of ethyl pyruvate after chiral modification with cinchonidine. Excellent catalytic activity and enantioselectivity were achieved. More importantly, these catalysts exhibited extraordinary stability and reusability during the reaction and could be reused at least 26 times without significant loss in catalytic activity and enantioselectivity.

•3DOM-SrTiO3/Ag/Ag3PO4 ternary Z-scheme photocatalysts are firstly fabricated.•Notably enhanced photocatalytic performance is obtained compared with pure Ag3PO4.•The separate efficiency of carriers could be notably improved in these ternary composites.•The slow photon effect of 3DOM-SrTiO3 could improve light harvesting efficiency of catalysts.•3DOM-SrTiO3/Ag/Ag3PO4 composites exhibits increased durability due to the Z-scheme mechanism.The novel visible-light-driven 3DOM-SrTiO3/Ag/Ag3PO4 ternary composites were fabricated and used as photocatalysts in the degradation of organic contaminants, including RhB, phenol, and MB. Through the XRD, SEM, TEM, DR UV–vis, XPS, PL spectroscopy, N2 sorption, and photoelectrochemical measurement, the obtained 3DOM-SrTiO3/Ag/Ag3PO4 ternary composites were well characterized. The effects of SrTiO3:Ag3PO4 molar ratio and stop-bands of 3DOM-SrTiO3 on the catalytic performance were systemically investigated. 3DOM-SrTiO3/Ag/Ag3PO4 ternary composite photocatalysts exhibited notably enhanced activity compared with single 3DOM-SrTiO3 and Ag3PO4 catalyst. Among these ternary photocatalysts, S35A65(300) exhibited the most excellent photocatalytic performance under visible light irradiation, which could be mainly attributed to synergy effect of the notably improved separate efficiency of photogenerated electron-hole pairs and the suitable stop-bands of 3DOM-SrTiO3(300) material. Although the gradually reduced activity in cycling tests was obtained over S35A65(300) under visible light irradiation, an excellent durability could be achieved for S35A65(300) under UV–vis light irradiation. No obvious loss in photocatalytic efficiency was observed after six cycles for RhB degradation. The notably improved enhanced durability of 3DOM-SrTiO3/Ag/Ag3PO4 ternary composites under UV–vis light irradiation could be mainly attributed to the Z-scheme mechanism of this ternary composite photocatalyst.Download high-res image (108KB)Download full-size image

In this paper, the selective hydrogenation of halonitrobenzenes (HNBs) to haloanilines (HANs) under mild conditions catalyzed by well-dispersed Pt nanoparticles protected by thiol-terminated poly(N-isopropyl acrylomide) (PNIPAM-SH) was firstly investigated. The polymer not only protected the Pt nanoparticles, but also inhibited the highly active Pt catalyst from producing undesired hydrodehalogenation products through anchoring the thiol groups to the surface of Pt nanoparticles. Thus high selectivities to HANs were achieved over this modified Pt catalyst for a variety of HNBs with satisfactory catalytic activities. Especially, the selectivity to HANs showed no obvious loss with the prolonging of the reaction time. Moreover, the recycling experiment showed that this Pt nanocatalyst was easier to recover and reuse based on the cononsolvency of PNIPAM-SH. Excellent stability and reusability were presented over this catalyst, and both the catalytic activity and selectivity were well maintained after fourteen runs.

Hierarchical walnut-like Ni0.5Co0.5O hollow nanospheres (NCO-HNS) were successfully synthesized via a facile and effectual hard-template method. Layered Ni0.5Co0.5O nanosheets stacked by several ultra-thin layers with the thickness of 2–3 nanometers were self-assembled into the hollow nanospheres. This unique hierarchical architecture, including micro-, meso-, and macropores, could provide a large specific surface area (123.7 m2 g−1) and efficient channel for the diffusion of ions and electrons, as well as the penetration of electrolyte. Significantly, the as-prepared NCO-HNS exhibit an excellent specific capacity of 221.9 mA h g−1 at the current density of 1 A g−1, a remarkable rate capability (172.8 mA h g−1 at 20 A g−1) and capacity retention (99.4% after 3000 cycles). Moreover, the NCO-HNS was then successfully fabricated into hybrid devices with active carbon. These devices deliver a maximum energy density of 38.3 W h kg−1 (31.8 W h L−1) at the power density of 743.5 W kg−1. Note that because of the morphology and hierarchical architecture, the energy density of the device could still maintain 19.3 W h kg−1 (16.0 W h L−1) even at an ultra-high power density of 7604.9 W kg−1. These hierarchical walnut-like Ni0.5Co0.5O hollow nanospheres comprising layered nanosheets may have potential as battery-type electrode materials for advanced energy storage devices.

•Visible-light-driven ternary CdS/Au/3DOM-SrTiO3 composites are firstly synthesized.•CdS/Au/3DOM-SrTiO3(300) exhibits extra high hydrogen evolution rate (5.39 mmol/g h).•Notably enhanced apparent quantum efficiency (42.2% at 420 nm) is achieved.•The synergistic enhancement mechanism of CdS/Au/3DOM-SrTiO3 composites is demonstrated.•The as-synthesized CdS/Au/3DOM-SrTiO3 composites are quite stable.New ternary composites based on three dimensionally ordered macroporous (3DOM) SrTiO3 (CdS/Au/3DOM-SrTiO3) were prepared and used as photocatalysts in visible light (λ > 420 nm) photocatalytic water splitting for hydrogen evolution. Through optimizing the pore size of 3DOM-SrTiO3 materials and the loading amounts of Au and CdS, CdS/Au/3DOM-SrTiO3(300), templated by 300 nm sized poly(methyl methacrylate) colloids, was found to exhibit a remarkably enhanced photocatalytic hydrogen evolution rate (2.74 mmol/h⋅g), which was 3.2 times as high as that of CdS/Au/C-SrTiO3 catalyst based on commercial SrTiO3. This notably enhanced photocatalytic performance was mainly attributed to the slow photon enhancement effect of 3DOM-SrTiO3(300) material, which significantly promoted the light harvesting efficiency of ternary composite for the slow photon region of 3DOM-SrTiO3(300) was well matched with the optical absorption band of photocatalyst. Further depositing Pt nanoparticles on CdS/Au/3DOM-SrTiO3(300) composite as a co-catalyst, an extraordinarily high hydrogen evolution rate (up to 5.46 mmol/g⋅h) and apparent quantum efficiency (42.2% at 420 nm) were achieved because of the synergistic effect of efficient carrier separation, Au SPR effect, and slow photon effect. Furthermore, these ternary CdS/Au/3DOM-SrTiO3 composite photocatalysts were very stable and could be easily recycled four times in visible light photocatalytic water splitting experiments without any loss in activity.The ternary CdS/Au/3DOM-SrTiO3 composites were prepared and used in hydrogen evolution from water splitting under visible light (λ > 420 nm) irradiation. An extraordinarily high hydrogen evolution rate (up to 5.46 mmol/g h) with AQE420nm of 42.2% was achieved over CdS/Au/3DOM-SrTiO3(300) using Pt as co-catalyst, which could be mainly attributed to the synergistic enhancement effect of efficient carrier separation, SPR effect of Au, and slow photon effect of 3DOM-SrTiO3(300).Download high-res image (146KB)Download full-size image

•3DOM-SrTiO3 photocatalysts with different pore sizes are firstly prepared.•The highest H2 production rate is obtained compared with reported SrTiO3 catalysts.•H2 evolution rate of 3DOM-SrTiO3(270 nm) is 31 times as high as that of SS-SrTiO3.•The notably enhanced activity is attributed to the slow photon effect of 3DOM-SrTiO3.•3DOM-SrTiO3 catalysts exhibit excellent durability in solar water splitting reaction.Three-dimensionally ordered macroporous SrTiO3 (3DOM-SrTiO3) materials with different pore sizes were originally prepared and employed as photocatalysts in the water splitting for hydrogen generation. These 3DOM-SrTiO3 photocatalysts were characterized by XRD, SEM, TEM, EDS, DR UV–vis and N2 sorption. Because of the slow photon effect of 3DOM-SrTiO3, notably enhanced efficiency of water splitting for hydrogen evolution was obtained compared with the solid-state SrTiO3 (SS-SrTiO3) and disordered porous SrTiO3 (Disorder-SrTiO3). The effect of stop-band on the efficiency of photocatalytic hydrogen production was studied by tuning the pore diameter of 3DOM-SrTiO3. It was found that higher hydrogen evolution efficiency could be achieved when the photonic stop-band of 3DOM-SrTiO3 was overlapped with its band gap, which was further confirmed by the control experiments under certain wavelength light irradiation. 3DOM-SrTiO3(270 nm) exhibited the highest photocatalytic hydrogen evolution rate (up to 3599 μmol/g·h), which was 31 times as high as that of SS-SrTiO3 and 11 times higher than that of Disorder-SrTiO3. Furthermore, these 3DOM-SrTiO3 catalysts were very stable and no obvious loss in photocatalytic efficiency of hydrogen production was observed after five cycles.Download high-res image (382KB)Download full-size image

•Pt nanocatalyst supported on 3DOM carbon is firstly used in asymmetric hydrogenation.•Higher activity and comparable enantioselectivity than Pt/Al2O3 are achieved.•Supported Pt catalyst shows excellent reusability and can be reused 13 times.Pt nanoparticles supported on three-dimensionally ordered macroporous carbon (Pt/3DC) were prepared and applied as catalyst after chirally modified with cinchonidine for the enantioselective hydrogenation of ethyl pyruvate. The catalyst was characterized by SEM, TEM, powder XRD, N2 sorption, and CO chemisorption, which confirmed the well-defined periodic macroporous structure of Pt/3DC and the high dispersion of Pt nanoparticles on the support. High catalytic performance was achieved over chirally modified Pt/3DC catalyst in the asymmetric hydrogenation of ethyl pyruvate. A high turnover frequency of 11,800 h−1 with an enantiomeric excess of 79.5% was acquired in acetic acid. In particular, this catalyst exhibited high durability in the asymmetric hydrogenation system and could be easily reused at least 13 times with well-maintained catalytic activity and slightly decreased enantioselectivity. Moreover, the comparison of catalytic performance between Pt/3DC and commercial Pt/C as well as Pt/Al2O3 was carried out.Download high-res image (342KB)Download full-size image

•Ni0.54Co0.46O2 grown on carbon fibers as binder-free electrode for supercapacitor directly.•The coexistence of Ni2+ and Ni3+ in Ni0.54Co0.46O2 could boost the performance.•The products exhibit outstanding specific capacity and rate performance.•Symmetrical device delivers excellent energy density and power density.Hierarchical Ni0.54Co0.46O2 architectures composed by nanowires or nanosheets were successfully grown on bio-mass carbon fiber cloth (CFC) by hydrothermal method. The morphology of Ni0.54Co0.46O2 can be effectively controlled by using different precipitators. The structural effects of the two kinds of morphologies were researched. the results suggest that the Ni0.54Co0.46O2 nanosheet arrays grown on CFC (NCO-NSs/CFC) shows a higher Faradaic areal capacity of 438 μAh cm−2 (238.1 mAh g−1) at a current density of 1 mA cm−2 and still about 90.3% initial capacity retention even at the high current density of 50 mA cm−2. Moreover, an all-solid-state flexible symmetric supercapacitor device has been successfully assembled. The optimized device delivers superior electrochemical performance with an outstanding energy density of 92.4 Wh kg−1 at a power density of 207.2 W kg−1. Such hierarchical nanostructure composed by well-aligned uniform Ni0.54Co0.46O2 nanosheet arrays grown on bio-mass carbon fiber cloth might hold great promise as battery-type electrode material for high-performance supercapacitor.

An environmentally benign and homogeneous base-free route for 5-hydroxymethyl-2-furfural (HMF) aerobic oxidation to 2,5-furandicarboxylic acid (FDCA) in water was reported using Mg–Al–CO3 hydrotalcite-supported Pd nanoparticles (xPd/HT-n) as catalyst. The influences of the Mg/Al molar ratio of hydrotalcite and Pd loading amount on the catalytic performance of these catalysts were originally systematically investigated. These catalysts exhibited excellent catalytic activity and FDCA selectivity in the HMF oxidation, especially for 2%Pd/HT-5 and 2%Pd/HT-6; >99.9% FDCA yields were achieved for 8 h under ambient pressure and homogeneous base-free conditions. The remarkably improved catalytic performance could be attributed to the suitable basicity of the Mg–Al–CO3 hydrotalcite and the abundant OH– groups on the surface of hydrotalcite. The plausible reaction mechanism was proposed based on the results of a series of controlled experiments. Furthermore, these catalysts were quite stable and could be reused at least five times without obvious loss in reaction activity.Keywords: 5-Hydroxymethyl-2-furfural; Aerobic oxidation; Basicity tuned; Homogeneous base-free; Mg−Al−CO3 hydrotalcite

•HPCNFs are fabricated by electrospinning.•DMF/THF mixed solvent can disperse CaCO3 uniformly in precursor solution.•The HPCNF mats are binder-free using to electrode.•Excellent electrochemical performances are achieved.1D hierarchical porous carbon nanofibers (HPCNFs) are prepared via electrospinning ternary PAN/N, N’-dimethylformamide (DMF)/tetrahydrofurar (THF) and using commercially available nano-CaCO3 as template. In the process of carbonization, nano-CaCO3 template decomposes and releases CO2 to form micropores and mesopores. Macropores are generated by removing the CaO nanoparticles using acid subsequently. The hierarchical pores are fairly well distributed because the nano-CaCO3 particles are highly dispersed in the fiber due to the better wettability in binary solvent. The obtained HPCNFs attain high specific surface area without physical and chemical activation. The HPCNF mats, possessing free-standing architecture, are used as binder-free electrodes for supercapacitor. Because of high specific surface area, rational pore diameter distribution and binder-free characterization of electrodes, the HPCNFs display a high capacitance of 251 F g−1 at a current density of 0.5 A g−1 as well as excellent rate capability and outstanding cycling stability (over 88% capacitance retention after 5000 cycles at the current density of 1 A g−1). These results demonstrate that the binary solvent method is effective to achieve high-performance electrode materials and it has a promising prospect on applications of energy storages.

Multichannel carbon nanofibers (MCNFs) have been fabricated by annealing electrospun PAN/PS immiscible polymer nanofibers. The obtained mechanically flexible mats of MCNFs, possessing an integrative architecture, are used as an electrode directly with no binder and without any activation processes. Owing to the binder-free characteristic, unique multichannel structure and high specific surface area, the MCNFs show high capacitance (270 F g−1 at a current density of 0.5 A g−1), perfect cycling stability (the capacitance does not decrease after 5000 cycles at a current density of 1 A g−1), excellent rate capability (89% retention at a current density of 20 A g−1) and high energy and power density. These results demonstrate that the electrode material has a promising prospect in applications of energy storage.

•Dealuminated HMCM-68 zeolites were prepared by steaming or acid leaching.•Their catalytic properties were studied using the alkylation of phenol with TBA.•HMCM-68 modified by citric acid for 8 h (CAZ8) showed the best catalytic activity.•CAZ8 had improved adsorption polarity and enlarged pore volume.•Both of the improved structural and acidic properties played important roles.A series of dealuminated HMCM-68 zeolites were prepared by treatment with steaming or hydrochloric/citric acid leaching. Their catalytic properties were studied using the alkylation of phenol with tert-butyl alcohol as a test reaction. The HMCM-68 zeolite modified by citric acid for 8 h (CAZ8) showed the best catalytic performance due to its improved structural and acidic properties, confirmed by methods of XRD, ICP-AES, SEM, N2-adsorption, 27Al MAS NMR and NH3-TPD. Furthermore, it is proposed that citric acid treatment is the most suitable method for dealumination of HMCM-68 zeolite in the alkylation of phenol, which results in the zeolites having improved adsorption polarity, as well as enlarged surface area and pore volume for the desired transformation. The factors affecting the reaction over CAZ8 have also been extensively investigated.

•Easy preparation method based on hydrothermal treatment.•Unique hierarchical porous structure with interconnected micro-, meso- and macroporous network.•Excellent electrochemical performances as capacitor electrode material.Three-dimensionally (3D) hierarchical porous carbon has been prepared through a simple and efficient hydrothermal treatment on colloidal silica as template. Nitrogen adsorption-desorption isotherms and transmission electron microscope images reveal that the porous carbon has a unique 3D interconnected micro-, meso- and macroporous network. The observed 3D interconnected meso/macroporous network originates from the cores of carbon hollow-spheres and the aggregation of crosslinked carbon hollow-spheres, and the micropores exist from the 3D interconnected network inside the shells of carbon hollow-spheres. The electrochemical capacitive tests indicate that the porous carbons exhibit large specific capacitance of about 300 F g−1 at 1 A g−1 in 6 M KOH aqueous electrolyte as well as high capacitance retention of 71% when the current density increased by 10 times.

Effective in situ redox, epitaxial assembly of Cu2O@Ag and Ag cages in high yields were acquired through introducing [Ag(NH3)2]+ complexant to a dispersed Cu2O suspension under visible-light irradiation, in the absence of any other chemical. The [Ag(NH3)2]+ complexant plays a critical role in the Ag-shell growth and duplicating the morphology of the Cu2O template.

•Ag3PO4/WO3 exhibited notably higher activity and stability than pure Ag3PO4 and WO3.•The catalyst with Ag3PO4:WO3 mass ratio of 6:4 exhibited the highest activity.•After photodegradation less Ag0 was detected on the surface of Ag3PO4/WO3 than Ag3PO4.•Ag3PO4 was effectively protected due to the special transfer pathway of electron.The Ag3PO4/WO3 composites were prepared through a deposition–precipitation method and characterized by XRD, SEM, and DR UV–vis. These photocatalysts were evaluated in the degradation of rhodamine B (RhB) and methyl orange (MO) under visible light irradiation (λ > 420 nm), and the synergistic effect of Ag3PO4 and WO3 was confirmed by notably higher photocatalytic activity compared to pure Ag3PO4 and WO3 catalysts. The effect of Ag3PO4:WO3 ratio on the catalytic activity was systemically studied and the catalyst AW6/4 was found to exhibit the highest catalytic activity. The degradation rates of RhB and MO could reach up to 97% under visible light irradiation for 6 min and 35 min, respectively. Moreover, the Ag3PO4/WO3 photocatalysts showed higher recyclability than pure Ag3PO4 catalyst and could be recycled five runs in the degradation of RhB without any loss in the activity. The characterization of used catalysts proved that Ag3PO4 was effectively protected and much less metallic Ag was formed on the surface of Ag3PO4/WO3 catalyst. The improvement of photocatalytic activity and stability is mainly attributed to the highly effective separation of photogenerated electron–hole pairs and special transfer pathway of electrons and holes in Ag3PO4/WO3 composites.The Ag3PO4/WO3 composites with improved activity and stability were prepared and employed as catalyst for the visible light degradation of RhB and MO. Due to the special transfer pathway of electron, Ag3PO4 was effectively protected and much less metallic Ag was formed on the surface of Ag3PO4/WO3.

Honeycomb hierarchical porous carbon (HHPC) with interconnected meso/macropore and abundant micropore has been synthesized by an easy solvent evaporation method. The obtained HHPC as an electrode material exhibits good capacitive performances with a long cyclic life, a high specific capacitance of 292 F g−1 at 1 A g−1 in KOH aqueous electrolyte, and a low capacitance loss of 20% when the current density increased by 10 times.Highlights► Easy preparation method based on solvent evaporation. ► Unique hierarchical porous structure with interconnected meso/macropore and abundant micropore. ► Excellent electrochemical performances as capacitor electrode material.

Pd nanoparticles supported on MnOx (Pd/MnOx-ads) have been synthesized via the adsorption method and characterized using X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy techniques. The Pd nanoparticles with an average of 1.8 nm were highly dispersed on MnOx and Pd2+ ions were partially reduced to Pd0. Pd/MnOx-ads exhibited high activity and selectivity to benzaldehyde for the aerobic oxidation of benzyl alcohol without any solvent, compared with Pd/Mn3O4, Pd/CeO2 and Pd/Fe3O4 catalysts. Moreover, Pd/MnOx-ads showed remarkably higher activity than the catalysts prepared by adsorption-reduction and co-precipitation methods. The catalyst can be reused several times without obvious loss of its activity.

•Functionalized imidazolate mesoporous supports were prepared by co-condensation.•Immobilized chiral Mn(III) salen catalysts showed excellent catalytic performance.•Notably high TOF values (up to 165 h−1) were obtained for olefin epoxidation.•Co-condensed supports were better than the post-functionalized materials.•Bigger support pore sizes gave better catalytic performance.The heterogeneous chiral Mn(III) salen catalysts with ordered hexagonal mesostructure were prepared based on mesoporous materials functionalized by imidazole groups through a co-condensation procedure. These catalysts were highly active and enantioselective for the asymmetric epoxidation of olefins. Within a short reaction time, comparable conversion and enantiomeric excess to those of the homogeneous counterpart were obtained even with a very low catalyst dosage (0.60 mol%). Thus notably high turnover frequencies (up to 165 h−1) were provided by these catalysts, attributed in part to the homogeneous distribution of the active centers as well as the strong electron-donating ability of imidazole groups. Comparison experiments showed that these catalysts were twice more active than the catalysts supported on the mesoporous material graft-modified with imidazole. Furthermore, the nanopore size of mesoporous hybrid supports was found to have a considerable effect on the catalytic performance.

•Unsymmetric chiral Mn(III) salen complexes were immobilized on mesoporous silica.•Great difference in reactivity was observed with different oxidants.•UV–vis spectra and reaction kinetics were employed to analyze the difference.Unsymmetric Mn(III) salen complexes were synthesized through a facile method and grafted on several mesoporous silica (MCM-41, MCM-48 and SBA-15). The spectra of FT-IR and DR UV–vis indicated that the Mn(III) salen complexes were immobilized successfully and the characterization of XRD and N2 sorption proved that the mesoporous structures of supports were kept well after grafting of Mn(III) salen complexes. These heterogeneous catalysts were evaluated by the asymmetric epoxidation of unfunctionalized olefins. Comparable activity and enantioselectivity to the homogeneous catalysts were obtained. Two kinds of oxidants were employed and great difference was observed in the catalytic performance of heterogeneous epoxidation of olefins, although in homogeneous conditions m-CPBA and NaClO almost obtained the same reactivity in this reaction. The heterogenization of Mn(III) salen complexes gave different influence for two oxidation systems. Compared with m-CPBA (m-chloroperbenzoic acid), the reaction oxidated by NaClO exhibited higher conversions in heterogeneous conditions, and the reason was discussed with the aid of UV–vis spectra and reaction kinetics.

The influence of small organics on the adsorption characteristics of activated carbon produced from industrial pyrolytic tire char (APTC)for malachite green (MG) was investigated by a batch method. Phenol was chosen as the representative of small organics. The effects of phenol on adsorption equilibrium, kinetics and thermodynamics were studied systematically. The results indicate that APTC is a potential adsorbent for MG. The presence of phenol decreases the adsorption capacity of APTC for MG, but improves the rate of adsorption, while the adsorption characteristics, such as equilibrium, kinetics and thermodynamics are not affected by phenol. The adsorption equilibrium data follow Langmuir isotherm and the kinetic data are well described by the pseudo-second-order kinetic model. The adsorption process follows intra-particle diffusion model and the adsorption rate is determined by more than one process. Thermodynamic study shows that the adsorption is an endothermic and spontaneous physisorption process.

Dispersed carbon hollow-spheres with micropore shells and meso/macropore cores are prepared through a simple and efficient hydrothermal treatment directly using colloidal silica as template. The as-prepared hollow spheres are used as supercapacitor electrode material and exhibit high specific capacitance (about 270 F g−1 at 0.5 A g−1 in KOH aqueous electrolyte), long cyclic life and excellent rate capability, which is applicable for high performance electrical double-layer capacitors.Highlights► Novel preparation method directly using colloidal silica as template. ► Unique hierarchical porous structure with micropore shell and meso/macropore core. ► Excellent electrochemical performances as capacitor electrode material.

Two kinds of chiral Mn(III) salen complexes were synthesized and directly immobilized on pyrolytic waste tire char (PWTC) without modification of any organosilicon, which was an economic support, having rich oxy functionalized groups inherently. The as-prepared heterogeneous catalysts were characterized by X-ray photoelectron spectra (XPS), N2 sorption, Fourier transform infrared spectra (FT-IR) and thermogravimetric analysis (TG), and possessed of good catalytic performance in asymmetric epoxidation of unfunctionalized olefins. They obtained higher enantiomeric excess (ee) values than that of homogeneous catalysts for asymmetric epoxidation of 1-phenylcyclehexene and could be recycled three times.Chiral Mn(III) salen complexes were synthesized and directly immobilized on pyrolytic waste tire char (PWTC) without modification of any organosilicon. The obtained heterogeneous catalysts showed high conversions and good enantioselectivities in asymmetric epoxidation of unfunctionalized olefins.Highlights► The pyrolytic waste tire char (PWTC) was firstly used as a support in asymmetric epoxidation. ► Chiral Mn(III) salen complexes directly immobilized on PWTC without any organosilicon were reported firstly. ► The heterogeneous catalysts showed great catalytic performance.

Mesoporous materials, especially functionalized ones, have become a promising carrier for enzyme immobilization. We synthesized room temperature ionic liquid-decorated mesoporous SBA-15 (RTIL-SBA-15) for papain immobilization. The results of powder XRD, IR and N2 adsorption–desorption isotherms have confirmed that ionic liquid [Simim+][Cl−] was successfully grafted on the surface of SBA-15. As a consequence of the electrostatic attraction between the cation [Simim+] and the negatively charged papain, RTIL-SBA-15 had an advantage over SBA-15 when papain was immobilized at pH = 9.00. The kinetic study showed that the interaction between papain and the carrier was stronger after ionic liquid modification. In the casein hydrolysis, the papain immobilized on RTIL-SBA-15 showed a higher specific activity than that on SBA-15, implying that the ionic liquid [Simim+][Cl−] was beneficial to improve the activity of the immobilized papain. The optimum pH of the immobilized papain was shifted to higher than that of free enzyme.Highlights► Ionic liquid [Simim+][Cl−]-decorated SBA-15 (RTIL-SBA-15) was synthesized. ► RTIL-SBA-15 had a more papain loading than SBA-15 at pH = 9.00. ► RTIL-SBA-15 had a higher Langmuir affinity constant than SBA-15. ► [Simim+][Cl−] was beneficial to improve the activity of the immobilized papain. ► Optimum pH of the immobilized papain was shifted to higher than that of free enzyme.

Titanosilicate ETS-4 materials with three different morphologies were synthesized hydrothermally by controlling the pH of the synthesis gel mixtures. Their morphology changed from thin rectangular plate monolithic crystals to double-fan-like polycrystalline aggregates as the pH decreased. The crystallization time depended on the initial pH. The effect of morphology on photocatalytic activity was investigated using the photodegradation reaction of Rhodamine B under visible light irradiation. The double-fan-like material exhibited significantly greater photodegradation activity than the other two ETS-4 samples and Degussa P25 titania. Powder X-ray diffraction, electron microprobe analysis, scanning electron microscopy, Raman spectroscopy, and diffuse reflectance ultraviolet−visible spectroscopy were performed to find possible reasons for the photocatalytic activity difference of the three samples. The enthalpies of formation from oxides for all the ETS-4 materials were investigated by high temperature oxide melt calorimetry. The results showed that the three samples with different morphologies have differences in their enthalpies of formation, which, although small, are bigger than likely to arise from surface area effects alone, and the product with most Ti−OH groups has the smallest thermodynamic stability. The calorimetric and spectroscopic data together provide evidence that the high photocatalytic activity of the double-fan-like aggregates is linked to their high Ti−OH content.Keywords: calorimetry; enthalpy of formation; ETS-4; morphology; photocatalysis;

Pyrolytic waste tire char was modified to be used as support and a series of catalysts supported with 0.1–1.0 wt% Pt were prepared by conventional wetness impregnation method. TEM images show that the Pt nanoparticles are well-dispersed in any microregions in the sample view on the TEM grid. The results of methylcyclohexane dehydrogenation reaction show the Pt loadings and the reaction temperature have a significant impact on the catalytic activity.Highlights► Purified carbon materials with high surface area were obtained via modification of pyrolytic waste tire char. ► The Pt nanoparticles (around 2.5 nm) are well dispersed on the surface of the carbon materials support. ► The Pt catalyst exhibites 100% selectivity and over 95% conversion on methylcyclohexane dehydrogenation reaction. ► The Pt loading and the reaction temperature have strongly effect on the performance of prepared catalysts.

Carboxyl-modified mesoporous materials have been demonstrated as efficient carriers for immobilizing enzymes. However, little attention has been paid to the effect of H2SO4 treatment, a key in the synthesis of carboxyl-modified carriers, on the immobilization. To examine the H2SO4 treatment’s influence, we contrasted the ability of immobilizing papain between SBA-15 and the one after H2SO4 treatment (H2SO4-treated SBA-15). Meanwhile, the contribution of the as-synthesized carboxyl to the immobilization was also rechecked by comparing carboxyl-modified SBA-15 (COOH-SBA-15) and H2SO4-treated SBA-15. In relation to the experiments, the H2SO4 treatment increases the immobilizing ability of SBA-15, especially when the immobilization performs near the pI of papain. Moreover, the as-synthesized carboxyl facilitates the immobilization by means of strengthening the hydrophobic dehydration at the interface, instead of merely through electrostatic forces. Additionally, the carboxyl makes a large contribution to inducing the favorable conformation change of papain, improving the specific activity, catalytic efficiency, and binding affinity of the immobilized enzyme when combined with the substrate.Graphical abstractThe carboxyl facilitates the immobilization of papain by means of strengthening the hydrophobic dehydration at the interface, instead of merely through electrostatic forces. Moreover, the carboxyl makes a large contribution to inducing the favorable conformation change of papain, improving the specific activity, catalytic efficiency, and binding affinity of the immobilized enzyme when combined with the substrate.Highlights► The H2SO4 treatment increased the immobilization ability of SBA-15. ► Carboxyl assisted to the immobilization through enhancing the hydrophobic dehydration. ► Carboxyl had a contribution on inducing the favorable conformation change of papain. ► Papain/COOH-SBA-15 has higher activity and catalytic efficiency than the free one. ► Papain/COOH-SBA-15 has higher binding affinity with the substrate than the free one.

3-Aminopropyltriethoxysilane modified mesoporous SBA-15 was used to load the NiBr2(PPh3)2 as a heterogeneous catalyst for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) when initiated by ethyl 2-bromoisobutyrate (EBriB) in toluene. Due to the Lewis acid sites formed by the surface silanol groups of the mesoporous material, some monomer conversions were much higher even than that catalyzed by the homogeneous catalyst NiBr2(PPh3)2 under the same reaction conditions while polydispersity indices (PDI) of the products still kept narrow (1.20–1.30). At the same time, the activity of the catalyst could be modulated by changing the quantity of the –NH2, SBA-15 and the free PPh3. In the recycling experiments, the recovered heterogeneous catalyst basically maintained its catalytic activity without any addition of new heterogeneous catalyst.Graphical abstractThe immobilized –NH2, free PPh3 and the surface silanol groups on the mesoporous material SBA-15 influence ATRP of MMA collectively. This heterogeneous catalyst is even more effective than the homogeneous catalyst without additional Lewis acid.Research highlights► By immobilizing NiBr2(PPh3)2 on 3-aminopropyltriethoxysilane functionalized SBA-15 as heterogeneous catalyst, Ni(II) species are separated from polymerization product effectively. ► With the added free PPh3, this heterogeneous catalyst could make the supported ATRP of MMA more effective even than the corresponding homogeneous reaction without the Lewis acid. ► Quantity of free PPh3, –NH2 and SBA-15 could regulate the monomer conversion and PDI of the product together. ► In the recycling reactions, this heterogeneous catalyst could keep catalytic ability well.

The 3-aminopropyl-functionalized mesoporous materials with various amounts of 3-aminopropyl groups and nanopore sizes were synthesized through direct co-condensation of tetraethoxysilane with 3-aminopropyltriethoxysilane (APTES) using alkyltrimethylammonium bromide as template and applied to immobilize chiral Mn(III) salen complex. All the mesoporous hybrids and heterogeneous catalysts had ordered hexagonal mesostructure with uniform pore size distributions. The obtained heterogeneous catalysts exhibited comparable conversion and enantiomeric excess to those of the homogeneous counterpart for the asymmetric epoxidation of olefins even with a very low catalyst dosage (0.6 mol%), which were thrice more active than the catalysts supported on the 3-aminopropyl graft-modified mesoporous silicas. The improved catalytic efficiency was mainly attributed to the homogeneous distribution of chiral Mn(III) salen complexes on the surface of co-condensation modified supports. Both the APTES dosage and nanopore size of mesoporous hybrid material were found to have great influences on catalytic performance, and the catalyst with suitable APTES content and larger pore size showed higher catalytic activity and enantioselectivity.Graphical abstractOrganic–inorganic hybrid mesoporous materials synthesized via co-condensation were used to immobilize chiral Mn(III) salen complex, and the obtained catalysts exhibited excellent catalytic performance for the asymmetric epoxidation of olefins, attributed mainly to the uniform distribution of active centers on the surface of supports.Research highlights► Hybrid mesoporous materials used as supports were synthesized by co-condensation. ► Immobilized chiral Mn(III) salen catalysts showed very high catalytic performance. ► Homogeneous distribution of active sites contributed to high catalytic performance. ► Nanopore sizes had a considerable effect on the catalytic performance.

Synthesis of hollow mesoporous silica microspheres (HMSM) through directed surface sol–gel process of tetraethylorthosilicate (TEOS) on the template of core–shell microspheres of polystyrene-co-poly(4-vinylpyridine) (PS-co-P4VP) in the presence of the CTAB surfactant in neutral aqueous solution at room temperature is discussed. Ascribed to the inherently pendent catalyst of the Lewis alkaline P4VP segment on the template surface of the PS-co-P4VP core–shell microspheres, the sol–gel process of TEOS is directed exclusively onto the template, and thus well-defined HMSM are fabricated. The thickness of the mesoporous silica shell of HMSM can be tuned by changing the weight ratio of the template of the PS-co-P4VP core–shell microspheres to the coating material of TEOS. Following this method of directed surface sol–gel process, well-defined HMSM with shell thickness ranging from 13 to 39 nm are synthesized. Transmission electron microscopy (TEM), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and nitrogen adsorption–desorption analysis are applied to characterize the synthesized HMSM.Graphical abstractResearch highlights► Sol-gel process is directed onto the microsphere template due to pendent catalyst. ► The sol-gel process produces well-defined hollow mesoporous silica microspheres. ► The shell thickness of hollow mesoporous silica microspheres can be easily tuned.

A facile method of preparing hierarchical hollow silica microspheres containing surface silica nanoparticles (HHSMs) through the sol–gel process of tetraethylorthosilicate employing a quasi-hard template of non-cross-linking poly(4-vinylpyridine) microspheres is proposed. The quasi-hard template contains the inherent catalyst of the basic pyridine group, and a few of the polymer chains can escape from the template matrix into the aqueous phase, which initiates the sol–gel process spontaneously both on the surface of the template used to prepare the hollow silica shell and in the aqueous phase to produce the surface silica nanoparticles. By tuning the weight ratio of the silica precursor to the quasi-hard template, HHSMs with a size of about 180 nm and a shell thickness ranging from 14 to 32 nm and surface silica nanoparticles ranging from 17 to 36 nm are produced initially through the deposition of surface silica nanoparticles onto the silica shell, followed by template removal either by calcination or solvent extraction. The synthesized HHSMs are characterized, and a possible mechanism for the synthesis of HHSMs is proposed.

Temperature dependent synthesis of micro- and meso-porous silica employing the thermo-responsive homopolymer poly(N-isopropylacrylamide) or the random copolymer poly(N-isopropylacrylamide-co-acrylic acid) as structure-directing agent (SDA) and Na2SiO3 as silica source is proposed. The thermo-responsive character of the SDA provides the advantages including (1) temperature dependent synthesis of microporous silica, hierarchically micro-mesoporous silica, and mesoporous silica just by changing the aging temperature below or above the low critical solution temperature of the thermo-responsive SDA, and (2) elimination of the thermo-responsive SDA from silica matrix by water extraction. The synthesis mechanism is discussed, and the effect of the aging temperature and the weight radio of SDA/Na2SiO3 on the synthesis of micro- and meso-porous silica are studied. Microporous silica, hierarchically micro-mesoporous silica and mesoporous silica with the surface area at 3.5−9.0 × 102 m2/g and the pore volume at 0.28−1.13 cm3/g and the average pore size ranging from 1.1 to 9.0 nm are synthesized. The strategy affords a new and environmentally benign way to fabricate porous silica materials, and is believed to bridge the gap between the synthesis of microporous and mesoporous silica materials.

A series of highly-active nickel and lanthanum co-doped SrTiO3 photocatalysts were synthesized via sol–gel process and their photocatalytic activities were evaluated by degradation of methylene blue (MB). The obtained samples were found by XRD, XPS and UV–vis to have a perovskite structure in which Ni and La atoms were incorporated into SrTiO3. After Ni and La doped into SrTiO3, the absorption edge of SrTiO3 powder was greatly shifted from 380 nm to 700 nm. Under a 100 W incandescent lamp irradiating for 14 h, a 100% of MB was degraded, which is much higher than those of pure SrTiO3 and commercial Degussa P25. The optimal range of Ni and La dopants is 0.1–1.0 mol%. The formation of a new absorption edge and the large surface area may be the main reasons for the high activity.The large band gap of pure SrTiO3 was reduced by doping Ni ions via forming an electron donor level between the valence band and the conduction band. The photocatalytic activity was further enhanced by co-doping La ions because the oxygen vacancies, which act as electron–hole recombination centers, were reduced through keeping the charge balance.

Four kinds of mesoporous material-supported ionic liquid phase catalysts containing chiral Ru complex were synthesized using mesoporous MCM-41, MCM-48, SBA-15 and amorphous SiO2, respectively. The results of N2 sorption and XRD indicated the successful immobilization of chiral Ru complex inside the channels of the mesoporous materials. These immobilized catalysts were evaluated in the asymmetric hydrogenation of aromatic ketones and the reaction conditions were optimized. Comparable catalytic activities and enantioselectivities to those of nonimmobilized counterpart were obtained. Moreover, all the four catalysts were stable and could be easily recovered for reuse for at least four times without obvious decrease in conversions and ee values. Especially, the SiO2-based catalyst still preserved high activity and enantioselectivity in the fifth run. The comparison experiments indicated that the two kinds of ionic liquids in the heterogeneous catalyst were beneficial to the enhancement of the stability of active species.Graphical abstract. The chiral Ru catalysts immobilized in the mesoporous material-supported ionic liquid phase were highly active, enantioselective and stable for the asymmetric hydrogenation of aromatic ketones.Research highlights▶ Chiral Ru complex was immobilized on mesoporous materials by ionic liquids. ▶ Immobilized catalysts showed as high catalytic performance as homogeneous one. ▶ Immobilized catalysts were stable and could be easily recovered for reuse. ▶ Both the two ionic liquids contributed to the high stability of immobilized catalyst.

An unsymmetric chiral Mn(III) salen complex was immobilized onto a series of MCM-41 and MCM-48 mesoporous materials with different pore sizes. The as-synthesized catalysts were characterized by XRD, FT-IR, DR UV-Vis, N2 sorption and XPS. The results indicated that chiral Mn(III) salen complex was immobilized into the nanopores of supports and the long-range mesoporous ordering of parent supports was maintained after the immobilization. The heterogeneous catalysts were evaluated in the asymmetric epoxidation of styrene, indene, and 1-phenylcyclohexene, and the effect of 3-mercaptopropyltrimethoxysilane dosage and fine-tuning of pore size on the catalytic performance was studied. It was found that the activity and enantioselectivity were closely correlated with the pore sizes of heterogeneous catalysts. The larger pore sizes of supports could lead to higher conversions and ee values.

A heterogeneous catalyst of Ir(I)-9-amino epi-cinchonine complex immobilized on the surface of mesoporous SBA-15 was firstly synthesized and used in the asymmetric transfer hydrogenation of aromatic ketones. Enhanced enantioselectivity compared with homogeneous catalyst was obtained at room temperature. Furthermore, the heterogeneous system with very low leaching of iridium can be easily regenerated.Enhanced enantioselectivities have been achieved in heterogeneous asymmetric transfer hydrogenation of aromatic ketones using a mesoporous SBA-15 supported Ir(I)-9-amino epi-cinchonine complex; moreover, the heterogeneous system with very low leaching of iridium can be easily regenerated.Open image in new window

The effects of Ni and La co-doping on the electronic structure of SrTiO3 were investigated by theoretical (DFT) and experimental work. The calculation results revealed that doping sites of La and Ni impurities had a great influence on geometric structure and electronic properties of SrTiO3. Pure SrTiO3 and doped SrTiO3 were synthesized through citrate sol–gel method. The as-synthesized photocatalysts were characterized by XRD, UV–visible absorption spectroscopy and nitrogen adsorption, and employed to degrade methylene blue. La/Ni co-doped SrTiO3 exhibited the highest activity. The experimental results were in good agreement with the calculation results.

An imidazole modified mesoporous material has been prepared through a co-condensation procedure and adopted to covalently anchor chiral Mn(III) salen complex. The active centers in the as-synthesized catalyst were presented in the form of ionic species. The results of XRD, FTIR, DRUV-Vis, and N2 sorption confirmed the successful immobilization of chiral Mn(III) salen complex inside the channels of the modified support and the maintenance of the mesoporous structure of parent support in the immobilized catalyst. This heterogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to those of the homogeneous counterpart in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, notably high turnover frequencies have been obtained over this heterogeneous catalyst for the relatively short reaction time and low catalyst amount, due in part to the ionic property as well as the uniform distribution of the active centers.

A stable, economic and high active catalyst for selective oxidation of benzyl alcohol (BzOH) was developed by treating ZSM-5 zeolite with sodium hydroxide solution. The changes resulted by alkali-treatment in crystallinity, composition, structure parameters and acidities of alkali-treated ZSM-5 zeolites were examined by XRD, ICP, N2 adsorption-desorption, scanning electron micrographs (SEM), temperature program desorption (TPD) and Fourier transform infrared spectroscopic (FT-IR). The results showed that the specific MFI structure was preserved and the intrinsic micropores were kept without obvious change, the amount of Lewis acid sites and the external surface area were evidently increased after alkali-treatment. Without any organic solvent, the catalytic performance of alkali-treated ZSM-5 zeolite was investigated in selective oxidation of BzOH with hydrogen peroxide (H2O2), and the effects of reaction temperature, reaction time, dosage of catalyst, dosage of H2O2 and SiO2/Al2O3 ratio of as-received zeolites on catalytic selective-oxidation of BzOH were investigated. The results showed that the conversion of BzOH and the selectivity to benzaldehyde (BzH) were about 53% and about 86% respectively under reflux for 4 h in water. At the same time, the catalyst was very stable and could be reused for more than six times.An effective ZSM-5 zeolite catalyst was prepared via alkali-treatment, which exhibited high activity for selective oxidation of benzyl alcohol to benzaldehyde (BzH). The catalytic performance was improved by increasing the amount of active sites (i.e., Lewis acid sites) with alkali-treatment, which can split the bridging Si–OH–Al groups to form framework Al-Lewis sites.

In the present research, CuO was abundantly and evenly dispersed onto the mesoporous molecular sieves MCM-41 via the following novel method: MCM-41 support was above all modified with organic silicanes; the organofunctionalized MCM-41 then coordinated with cupric ions; the ultrasonic washing and calcination were afterwards orderly performed on the as-synthesized sample. The resultant catalyst was characterized by nitrogen adsorption–desorption analysis, temperature-programmed reduction (TPR), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), and ICP-AES techniques. The influences of cupric ion concentration, different organic functional groups and the effects of the ultrasonic washing on the dispersion and loading amount of CuO were also investigated and discussed. A comparison was made between the present method and the simple ion-exchange of AlMCM-41 with copper nitrate. Shown by experiment, MCM-41 maintains its ordered mesoporous structure after the dispersion of CuO. Meanwhile, some CuO are dispersed on the external surface of MCM-41 in very small particles, while the others are dispersed inside the pores of MCM-41. The effective preparative strategy introduced in this paper is a very promising method for preparing MCM-41 supported metal oxide catalyst with high metal loading and dispersion.

Boroaluminosilicate with MFI zeotype (henceforth B-ZSM-5) was synthesized both via the direct synthesis where ZSM-5 was employed as crystal seed and the templating method by using TPABr as the structure-directing agent (SDA). Characterization based on its structure, bonding, surface acidity, and morphology was performed by powder X-ray diffraction (XRD), 11B MAS NMR spectrometry, FT-IR spectrometry, pyridine-chemisorption IR spectrometry, and scanning electron microscopy (SEM). The composition of the prepared zeolites was determined by ICP-AES; the zeolite framework stability was investigated by steam treatment. The differences in the physicochemical properties of B-ZSM-5 prepared by the two methods were compared and discussed. In the direct synthesis, increasing initial boron-substitution ratio concomitantly brings about increasing difficulty to prepare pure B-ZSM-5 and, MFI-type borosilicate (free of aluminum) cannot be synthesized; the highest SiO2/Al2O3 ratio=70.64 is received. B-ZSM-5 prepared by the templating method shows remarkable hydrothermal stability than its counterpart prepared by the direct synthesis.Boron-incorporated ZSM-5 zeolite was synthesized both via the direct synthesis and the templating method. The prepared B-ZSM-5 was characterized based on its structure, bonding, surface acidity, morphology, and chemical composition by a series of instrumental analysis and spectroscopic methods. The framework stability was investigated by the steam treatment. The differences in physicochemical properties of B-ZSM-5 prepared by the two methods were compared and discussed.

A series of manganese oxides (MnO, Mn3O4, Mn2O3 and MnO2) were prepared and firstly applied as heterogeneous catalysts for the liquid phase epoxidation of alkenes with 30% H2O2 in bicarbonate solution. Under our experimental conditions, MnO exhibited superior activity for the conversion of styrene to achieve ca. 100% with 92.4% selectivity of epoxide, compared to the other three manganese oxides as well as other metal oxides. Furthermore, recycling studies showed the good recyclability of MnO as a heterogeneous catalyst, which did not lose the catalytic activity after four reuses appreciably.Simple MnO, Mn3O4, Mn2O3, and MnO2 could catalyze the epoxidation of alkenes with cheap 30% H2O2, in which MnO exhibited highly recyclable activity.Download full-size imageHighlights► Simple MnOX were firstly used as catalysts for alkene epoxidation with 30% H2O2. ► MnO exhibited very high activity for the epoxidation of alkenes. ► The activity of MnO did not lose after four reuses appreciably.

A series of mesoporous MCM-41 and MCM-48 materials with different pore sizes were synthesized and used as supports to immobilize chiral Mn(III) salen complex. The heterogeneous catalysts were characterized by XRD, FT-IR, DR UV–vis, and N2 sorption, and the results indicated the successful immobilization of chiral Mn(III) salen complex. The confinement effect of pore size on the catalytic performance of the heterogeneous catalysts was studied for the asymmetric epoxidation of unfunctionalized olefins with m-chloroperoxybenzoic acid as an oxidant. It was found that the conversions and enantiomeric excess (ee) values were closely correlated with the pore sizes of parent supports. The catalysts immobilized on the large-pore mesoporous supports exhibited higher conversions, and for the catalysts immobilized on MCM-41 materials, the ee values improved with increasing pore size. However, for the MCM-48 material-supported catalysts, the compatible pore size of the support with the substrate was beneficial for obtaining higher enantioselectivity in olefin epoxidation.

A kind of chiral Mn(III) salen-containing ionic species was prepared and covalently anchored on mesoporous materials, including SBA-15, MCM-48, MCM-41, and amorphous SiO2, via imidazole modification. These catalysts were characterized by N2 sorption, XRD, FTIR, DR UV–vis, and elemental analysis. The results showed that the chiral Mn(III) salen complex was successfully immobilized inside the channels of the modified mesoporous materials and that the long-range mesoporous ordering of parent supports was maintained after the immobilization. These prepared catalysts were evaluated in the asymmetric epoxidation of unfunctionalized olefins with m-chloroperoxybenzoic acid as oxidant. Comparable or even higher enantioselectivity than that of homogeneous counterpart was obtained with similar catalytic activity. Moreover, these heterogeneous catalysts can complete epoxidation rapidly, thus providing notably high turnover frequencies, attributed in part to the ionic property of the active centers. The SBA-15-based catalyst showed the best performance in the epoxidation reaction. Furthermore, these immobilized catalysts were stable and could be recycled five times without loss of activity.

Hierarchical walnut-like Ni0.5Co0.5O hollow nanospheres (NCO-HNS) were successfully synthesized via a facile and effectual hard-template method. Layered Ni0.5Co0.5O nanosheets stacked by several ultra-thin layers with the thickness of 2–3 nanometers were self-assembled into the hollow nanospheres. This unique hierarchical architecture, including micro-, meso-, and macropores, could provide a large specific surface area (123.7 m2 g−1) and efficient channel for the diffusion of ions and electrons, as well as the penetration of electrolyte. Significantly, the as-prepared NCO-HNS exhibit an excellent specific capacity of 221.9 mA h g−1 at the current density of 1 A g−1, a remarkable rate capability (172.8 mA h g−1 at 20 A g−1) and capacity retention (99.4% after 3000 cycles). Moreover, the NCO-HNS was then successfully fabricated into hybrid devices with active carbon. These devices deliver a maximum energy density of 38.3 W h kg−1 (31.8 W h L−1) at the power density of 743.5 W kg−1. Note that because of the morphology and hierarchical architecture, the energy density of the device could still maintain 19.3 W h kg−1 (16.0 W h L−1) even at an ultra-high power density of 7604.9 W kg−1. These hierarchical walnut-like Ni0.5Co0.5O hollow nanospheres comprising layered nanosheets may have potential as battery-type electrode materials for advanced energy storage devices.