Yolk–shell structures with a unique three-dimensional (3D) open architecture offer great advantages for constructing advanced photocatalysts. However, metal sulfides with yolk–shell nanostructures were rarely reported. In this work, unique yolk–shell CdS microcubes are synthesized from Cd–Fe Prussian blue analogues (Cd–Fe-PBA) through a facile microwave-assisted hydrothermal process. Their formation mechanism is also proposed based on the anion exchange and Kirkendall effect process. Benefitting from structural merits, including a 3D open structure, small size of primary nanoparticles, high specific surface area, and good structural robustness, the obtained yolk–shell CdS microcubes manifest excellent performances for photocatalytic hydrogen evolution from H2O under visible-light irradiation. The photocatalytic H2 evolution rate is 3051.4 μmol h−1 g−1 (with an apparent quantum efficiency of 4.9% at 420 nm), which is ∼2.43 times higher than that of conventional CdS nanoparticles. Furthermore, the yolk–shell CdS microcubes exhibit remarkable photocatalytic stability. This work demonstrates that MOF-derived yolk–shell structured materials hold great promise for application in the field of energy conversion.

•Cd0.2Zn0.8S@UiO-66-NH2 nanocomposites were synthesized by a solvothermal method.•The obtained composites exhibited excellent photocatalytic activity and stability.•A H2 production rate of 5846.5 μmol h−1 g−1 was obtained over the optimal catalyst.•The optimal catalyst also showed a CH3OH production rate of 6.8 μmol h−1 g−1.•An efficient charge separation and transfer was observed in the composites.Metal-organic frameworks (MOFs), a new class of porous crystalline materials, have attracted great interest as fascinating materials for sustainable energy and environmental remediation. However, the functionalization and diversification of MOFs are still challenging and imperative for the development of highly active MOF-based materials. In this study, a series of Cd0.2Zn0.8S@UiO-66-NH2 nanocomposites with different UiO-66-NH2 contents were fabricated via a facile solvothermal method. The photocatalytic performances of the obtained Cd0.2Zn0.8S@UiO-66-NH2 nanocomposites were evaluated by photocatalytic H2 evolution and CO2 reduction under visible-light irradiation. The resultant hybrids exhibit significantly enhanced photocatalytic activity for hydrogen evolution and CO2 reduction as compared with pristine components, and the optimal UiO-66-NH2 content is 20 wt%. The composite can show a hydrogen evolution rate of 5846.5 μmol h−1 g−1 and a CH3OH production rate of 6.8 μmol h−1 g−1. The remarkable enhancement of the photocatalytic activity should be attributed to the efficient charge separation and transfer on the interface between Cd0.2Zn0.8S and UiO-66-NH2. Furthermore, the Cd0.2Zn0.8S@UiO-66-NH2 photocatalysts show excellent stability during photocatalytic hydrogen evolution and CO2 reduction. This work demonstrates that MOF-based composite materials hold great promise for applications in the field of energy conversion and environmental purification.Download high-res image (143KB)Download full-size image

In this work, we demonstrated the polyvinylpyrrolidone-assisted solvothermal synthesis of three-dimensional (3D) flowerlike Mn0.8Cd0.2S microspheres assembled from nanosheets. The as-synthesized products were characterized by using various methods including powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microcopy/selected area electron diffraction, elemental mapping, X-ray photoelectron spectroscopy, inductively-coupled plasma emission spectroscopy, N2 adsorption–desorption, UV-vis diffuse reflectance spectroscopy, photoluminescence spectroscopy and photoelectrochemical experiments. The possible formation mechanism of the unique structures was discussed. The resultant 3D flowerlike Mn0.8Cd0.2S architectures exhibit better photocatalytic activities for H2 evolution and CO2 reduction under visible light irradiation than the Mn0.8Cd0.2S nanoparticles. A hydrogen evolution rate of 3560.3 μmol g−1 h−1 and a CH3OH production rate of 10.7 μmol g−1 h−1 are achieved on the flowerlike Mn0.8Cd0.2S microspheres. Several possible reasons for the enhanced photocatalytic activity of the Mn0.8Cd0.2S hierarchical microspheres have been taken into consideration. In addition, the Mn0.8Cd0.2S microspheres are stable during the reaction and can be used repeatedly.

•Ag coated BiOBr0.2I0.8 nanosheet/graphene sheet-on-sheet composites were synthesized.•The obtained ternary composites exhibited excellent photocatalytic activity.•A synergistic effect between the three components of the composites was observed.•Both the h+ and OH were the active species in the degradation process.A series of visible light-responsive plasmonic Ag coated BiOBr0.2I0.8 nanosheets are grown on graphene by a combined solvothermal and photodeposition method. The ternary Ag/BiOBr0.2I0.8/graphene nanocomposites exhibit significantly enhanced photocatalytic activity than pristine BiOBr0.2I0.8 and the binary BiOBr0.2I0.8/graphene composite. When the loading amount of Ag is 1.0 wt%, the Ag/BiOBr0.2I0.8/graphene nanocomposite displays the highest photocatalytic activity. The rate constants for the ternary Ag/BiOBr0.2I0.8/graphene composite to degrade rhodamine B (RhB) and methylene blue (MB) are determined to be ∼5.28 and 5.57 times as large as those of pristine BiOBr0.2I0.8, respectively. The high photocatalytic activity is attributed predominantly to the hybridization of the surface plasmonic resonance (SPR) effect of Ag nanoparticles and the specific electronics effect of graphene, thus enhancing the separation of photogenerated charge carriers of BiOBr0.2I0.8. Meanwhile, the excellent adsorption capacity of graphene and the broad absorption in the visible light region also contribute to the enhancement of photocatalytic activity. Both the holes and hydroxyl radicals were the active species in the degradation process.

Novel visible-light-driven Cd0.2Zn0.8S/g-C3N4 inorganic–organic composite photocatalysts were synthesized by a facile hydrothermal method. The prepared Cd0.2Zn0.8S/g-C3N4 composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible diffuse reflection spectroscopy (DRS), photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) experiments. Under visible-light irradiation, Cd0.2Zn0.8S/g-C3N4 photocatalysts displayed a higher photocatalytic activity than pure g-C3N4 and Cd0.2Zn0.8S for hydrogen evolution and degradation of pollutants, and the optimal g-C3N4 content was 20 wt%. The optimal composite showed a hydrogen evolution rate of 208.0 μmol h−1. The enhancement of the photocatalytic activity should be attributed to the well-matched band structure and intimate contact interfaces between Cd0.2Zn0.8S and g-C3N4, which lead to the effective transfer and separation of the photogenerated charge carriers. Furthermore, the Cd0.2Zn0.8S/g-C3N4 photocatalysts showed excellent stability during photocatalytic hydrogen evolution and degradation of pollutants.

•Bi2Sn2O7/RGO composite were synthesized by a hydrothermal method.•Enhanced visible light absorption was observed in Bi2Sn2O7/RGO composite.•RGO acted as an electron-acceptor to hinder the charge recombination.•The resulting composite exhibited high visible light photocatalytic activity.In this work, a novel Bi2Sn2O7/reduced graphene oxide (RGO) nanocomposite was synthesized by a one-step hydrothermal method. The prepared composite was characterized by means of powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) emission spectroscopy and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the Bi2Sn2O7/RGO composite was investigated by the degradation of rhodamine B (RhB) and phenol. An increase in photocatalytic activity was observed for Bi2Sn2O7/RGO composite compared with pure Bi2Sn2O7 under visible light. The enhanced photocatalytic performance of the composite was mainly ascribed to the more effective charge separations and the excellent adsorption capacity of RGO. The composite maintained its ability to degrade pollutants efficiently, even after 4 cycles of photocatalysis. Further study proved that both the holes and hydroxyl radicals were the active species in the degradation process.

ZnIn2S4–g-C3N4 sheet-on-sheet nanocomposites with different g-C3N4 contents were synthesized by a facile hydrothermal method and characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microcopy (HRTEM), N2 adsorption–desorption, ultraviolet-visible diffuse reflection spectroscopy (DRS), photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) experiments. The photocatalytic activities of these samples were evaluated by the photocatalytic H2-production and degradation of organic pollutants (methyl orange and phenol) under visible-light illumination (λ > 420 nm). The results showed that the ZnIn2S4–g-C3N4 composite photocatalysts displayed higher photocatalytic activity than the pristine g-C3N4 and ZnIn2S4 both for H2-evolution and degradation of pollutants. The optimal g-C3N4 content was determined to be 40 wt%, and the corresponding H2-production rate was 953.5 μmol h−1 g−1, which was about 1.91 times higher than that of pure ZnIn2S4. The enhanced photocatalytic activity of ZnIn2S4–g-C3N4 composites should be attributed to the well-matched band structure and intimate contact interfaces between ZnIn2S4 and g-C3N4, which led to the effective transfer and separation of the photogenerated charge carriers. Moreover, the ZnIn2S4–g-C3N4 composites showed excellent stability during the photocatalytic reactions under visible light. A possible mechanism of the enhanced photocatalytic activity of ZnIn2S4–g-C3N4 composites was proposed and supported by the PL and PEC results.

In this study, a visible light responsive Cu3SnS4/reduced graphene oxide (RGO) photocatalyst has been synthesized by a facile one-step solvothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, N2 adsorption–desorption, UV–vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy. The photocatalytic activity of the Cu3SnS4/RGO composite under visible-light irradiation (λ > 420 nm) was evaluated by measuring the degradation of rhodamine B (RhB) and phenol. The results revealed that the Cu3SnS4 nanoplates dispersed uniformly on the RGO surface. The Cu3SnS4/RGO composite exhibited much higher photocatalytic activity than pure Cu3SnS4. The enhancement in photocatalytic activity is likely to be due to the synergistic effect of an improved adsorptivity of pollutants, an enhanced visible light absorption and an effective charge separation. In addition, the Cu3SnS4/RGO photocatalyst was stable during the reaction and could be used repeatedly.

•Novel 3D flowerlike Au/BiOBr0.2I0.8 composites were synthesized.•Enhanced visible-light absorption was observed in Au/BiOBr0.2I0.8.•Au nanoparticles could act as electron traps to promote the electron–hole separation.•The Au/BiOBr0.2I0.8 composites exhibited high visible-light photocatalytic activity.A series of 3D flowerlike Au/BiOBr0.2I0.8 composites with different Au contents have been synthesized by a hydrothermal combinated with photodeposition method. The as-prepared samples were characterized by power X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high-resolution transmission electron micrographs (HRTEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy. The photocatalytic activities of these Au/BiOBr0.2I0.8 composites under visible-light irradiation (λ > 420 nm) were evaluated by the degradation of methyl orange (MO), rhodamine B (RhB) and phenol. The results revealed that the Au/BiOBr0.2I0.8 composites exhibited much higher photocatalytic activities than pure BiOBr0.2I0.8. And the 0.6%Au/BiOBr0.2I0.8 sample exhibited the highest photocatalytic activity. The enhanced photocatalytic activity could be attributed to Au deposits by acting as electron traps and the surface plasma resonance effect of Au. A possible photocatalytic mechanism of Au/BiOBr0.2I0.8 composites was also proposed.Graphical abstract

•Bi7O9I3/RGO composite were synthesized by a solvothermal method.•Enhanced visible light absorption was observed in Bi7O9I/RGO composite.•RGO acted as an electron-acceptor to hinder the charge recombination.•The resulting composite exhibited high visible light photocatalytic activity.Bi7O9I3/reduced graphene oxide (RGO) composite with visible light response was fabricated by a facile solvothermal method. The prepared samples were characterized by means of powder X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), Raman spectra, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy. The photocatalytic activity of the Bi7O9I3/RGO composite was evaluated by the degradation of rhodamine B (RhB) and phenol under visible irradiation (λ > 420 nm). The results indicated that the Bi7O9I3 nanoplates dispersed uniformly on RGO surface. The photocatalytic activity of Bi7O9I3/RGO in degradation of RhB and phenol was 2.13 and 2.29 times that of pure Bi7O9I3, respectively. The enhanced photocatalytic activity can be attributed to more effective charge transportations and separations, the high pollutant adsorption performance, and the increased light absorption. In addition, the Bi7O9I3/RGO photocatalyst was stable during the reaction and can be used repeatedly.

A unique CoS-graphene sheet-on-sheet nanocomposite has been successfully prepared by anchoring CoS nanosheets on the surface of graphene nanosheets (GNS) with the assistance of the structure-directing agent of ethylenediamine. The shape and size of the introduced CoS nanosheets can be further adjusted by varying the amount of GNS. The unprecedented sheet-like CoS structure is believed to be matched well with GNS basically due to their similar two-dimensional structure with maximum contact areas between two components. The strong interaction between CoS and the underlying highly conductive graphene can facilitate fast electron and ion transport and improve structure stability of the composite. The composite with 26.2% GNS displays excellent electrochemical performance when evaluated as an anode for rechargeable lithium-ion battery. A larger-than-theoretical reversible capacity of 898 mAh/g can be delivered after 80 cycles at 0.1 C along with excellent high-rate cycling performance. The CoS-graphene sheet-on-sheet composite is also used for the first time as a photocatalyst with promising properties for the degradation of methylene blue.

Reduced graphene oxide (RGO) nanosheet-supported SnS2 nanosheets are prepared by a one-step microwave-assisted technique. These SnS2 nanosheets are linked with each other and dispersed uniformly on RGO surface. The SnS2-RGO sheet-on-sheet nanostructure exhibits good electrochemical performances as an anode material for lithium ion batteries. It shows larger-than-theoretical reversible capacities at 0.1 C and excellent high-rate capability at 1 C and 5 C. The composite is also for the first time identified as an excellent visible light-driven catalyst of rhodamine B and phenol with high degradation efficiencies. The removal rates of rhodamine B and phenol are 100 and 83.2%, respectively, for the SnS2-RGO composite, whereas these values are only 64.8 and 51.5% for pristine SnS2 after the same irradiation times. The outstanding electrochemical or photocatalytic performances of the composite have been attributed to the complementary effect of RGO and SnS2 in the perfect sheet-on-sheet composition nanostructure.Keywords: lithium ion batteries; photocatalyst; reduced graphene oxide; sheet-on-sheet; SnS2 nanosheet;

•3D carnation-flowerlike SnS2 hierarchical structures were synthesized.•The present synthetic approach is quite fast, simple and environmentally friendly.•The flowerlike SnS2 architectures exhibited high photocatalytic activity.•The flowerlike SnS2 architectures were stable and reusable in photocatalysis.Novel 3D carnation-flowerlike hexagonal SnS2 hierarchical structures have been successfully synthesized through a simple microwave-assisted solvothermal process. The as-prepared products were characterized by power X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high-resolution transmission electron micrographs (HRTEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The photocatalytic activity of the sample under visible-light irradiation (λ > 420 nm) was evaluated by the degradation of two different organic pollutants, rhodamine B (RhB) and phenol. The results reveal that the carnation-flowerlike SnS2 architectures show much higher photocatalytic activity than the SnS2 nanoparticles. The high catalytic performance of the SnS2 architectures comes from their hierarchical mesoporous structures, high BET surface area, high surface-to-volume ratios, and increased light absorbance. In addition, the SnS2 hierarchical architectures are stable during the photocatalytic reaction and can be used repeatedly.

Mesoporous silicas and Fe–SiO2 with worm-like structures have been synthesized using a room temperature ionic liquid, 1-hexadecane-3-methylimidazolium bromide, as a template at a high aging temperature (150–190 °C) with the assistance of NaF. The hydrothermal stability of mesoporous silica was effectively improved by increasing the aging temperature and adding NaF to the synthesis gel. High hydrothermally stable mesoporous silica was obtained after being aged at 190 °C in the presence of NaF, which endured the hydrothermal treatment in boiling water at least for 10 d or steam treatment at 600 °C for 6 h. The ultra hydrothermal stability could be attributed to its high degree of polymerization of silicate. Furthermore, highly hydrothermal stable mesoporous Fe–SiO2 has been synthesized, which still remained its mesostructure after being hydrothermally treated at 100 °C for 12 d or steam-treated at 600 °C for 6 h.Worm-like mesoporous silica and Fe–SiO2 with high hydrothermal stability have been synthesized using ionic liquid 1-hexadecane-3-methylimidazolium bromide as a template under the assistance of NaF at high temperature.Research highlights► Increasing aging temperature improved the hydrothermal stability of materials. ►Addition of NaF enhanced the polymerization degree of silicates. ► Mesoporous SiO2 and Fe–SiO2 obtained have remarkable hydrothermal stability.

Mesostructrured CeO2–TiO2 nanoparticles with different CeO2 contents have been successfully synthesized using ionic liquid (1-hexadecane-3-methylimidazolium bromide, C16MIM+Br−) as a template by a hydrothermal method. The prepared materials were characterized by means of X-ray diffraction (XRD), nitrogen adsorption–desorption, transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra analysis. The obtained CeO2–TiO2 materials exhibit large specific surface area and uniform pore sizes. Introduction of CeO2 species can effectively extend the spectral response from UV to visible area and enhance the surface hydroxyl groups of the mesoporous TiO2. The CeO2–TiO2 nanocomposites show high photocatalytic activity in the degradation of the p-chlorophenol aqueous solution under the UV or visible irradiation.Graphical abstractHighlights► Well-crystallized mesoporous CeO2–TiO2 can be obtained. ► Such material exhibits strong spectral response in the visible region. ► Introduction of CeO2 species enhances the surface hydroxyl groups of the catalyst. ► The obtained material shows high photocatalytic activity under UV or visible light.

Chromium-containing mesoporous silica material Cr-MSU-1 was synthesized using lauryl alcohol–polyoxyethylene (23) ether as templating agent under the neutral pH condition by two-step method. The sample was characterized by XRD, TEM, FT-IR, UV–Vis, ESR, ICP-AES and N2 adsorption. Its catalytic performance for oxidation of styrene was studied. Effects of the solvent used, the styrene/H2O2 mole ratio and the reaction temperature and time on the oxidation of styrene over the Cr-MSU-1 catalyst were examined. The results indicate that Cr ions have been successfully incorporated into the framework of MSU-1 and the Cr-MSU-1 material has a uniform worm-like holes mesoporous structure. After Cr-MSU-1 is calcined, most of Cr3+ is oxidized to Cr5+ and Cr6+ in tetrahedral coordination and no extra-framework Cr2O3 is formed. The Cr-MSU-1 catalyst is highly active for the selective oxidation of styrene and the main reaction products over Cr-MSU-1 are benzaldehyde and phenylacetaldehyde. Its catalytic performance remains stable within five repeated runs and no leaching is noticed for this chromium-based catalyst.Mesoporous Cr-MSU-1 with worm-like holes was synthesized by a novel two-step method. The Cr-MSU-1 material is highly active and stable for the selective oxidation of styrene.

Anatase mesostructured TiO2 nanocrystalline was prepared in a mixture of 1-butyl-3-methyl-imidazolium tetrafluoroborate (BMIM+BF4−) ionic liquid and water by a low temperature hydrothermal method. The obtained materials were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption–desorption. The existence of BMIM+BF4− enhanced the polycondensation and crystallization rate, which encouraged the formation of anatase crystal. The TiO2 particles were thermally very stable and thus resistant to anatase-rutile phase transformation during calcination at high temperatures. The anatase TiO2 showed high photocatalytic activity in the degradation of p-chlorophenol than that of the commercially available TiO2, Degussa P25. After 2 h reaction under the UV-irradiation of 250 W, the removing rate of p-chlorophenol was up to 96.3%.

HMS mesoporous molecular sieve was synthesized hydrothermally by using dodecylamine (DDA) as template and tetethylorthosilicalite (TEOS) as silicon source. The influence of the hydrothermal synthesis conditions on HMS particle size was studied systematically. The results showed that the smaller particle was obtained under the condition of DDA/SiO2=0.27, H2O/SiO2=66.7, EtOH/SiO2=6.5 mol and synthesis time of 18 h. The presences of additives (TW20, TW60, SP60 and Neopelex) also helped to the reduction of particle size. The HMS mesoporous molecular sieve with particle size around 60∼100 nm was obtained by using TW20 or TW60 as an additive. In addition, TEM image showed that HMS mesoporous molecular sieve with pariticle size about 20∼100 nm was synthesized in microemulsion.

•Mesoporous g-C3N4 nanosheets supported CdIn2S4 nanocomposites were synthesized.•The obtained composites exhibited excellent photocatalytic activity and stability.•The optimal composite showed a CH3OH-production rate of 42.7 μmol g−1 h−1.•An efficient charge separation and transfer was observed in the composites.Photocatalytic conversion of CO2 into hydrocarbon fuels using semiconductor photocatalysts has attracted great attention, which is considered as a promising approach to resolve the energy shortage and greenhouse effect. In this work, ordered mesoporous g-C3N4 (mpg-C3N4) nanosheets supported CdIn2S4 nanocomposites were successfully fabricated by a hard-template combinated with hydrothermal method. The hybrids showed highly efficient photocatalytic activities for the reduction of CO2 to CH3OH under visible-light irradiation. The optimized CdIn2S4/mpg-C3N4 photocatalyst exhibited a high CH3OH-production rate of 42.7 μmol g−1 h−1 at a mpg-C3N4 content of 20 wt%. This rate was 1.8 times higher than that of pure CdIn2S4. The significant enhancement of photocatalystic activity was mainly ascribed to the increased CO2 adsorption capacity and the improved separation and transfer of photogenerated electron-hole pairs at the intimate interface of CdIn2S4/mpg-C3N4 heterojunctions. Furthermore, the hybrid photocatalysts displayed excellent stability under visible-light. A possible mechanism of enhanced photocatalytic activity of CdIn2S4/mpg-C3N4 composite on photocatalytic reduction of CO2 was also proposed. This work may provide some useful information for the future design and practical application of multifunctional hybrid photocatalysts in photocatalytic reduction of CO2.Download full-size image

Yolk–shell structures with a unique three-dimensional (3D) open architecture offer great advantages for constructing advanced photocatalysts. However, metal sulfides with yolk–shell nanostructures were rarely reported. In this work, unique yolk–shell CdS microcubes are synthesized from Cd–Fe Prussian blue analogues (Cd–Fe-PBA) through a facile microwave-assisted hydrothermal process. Their formation mechanism is also proposed based on the anion exchange and Kirkendall effect process. Benefitting from structural merits, including a 3D open structure, small size of primary nanoparticles, high specific surface area, and good structural robustness, the obtained yolk–shell CdS microcubes manifest excellent performances for photocatalytic hydrogen evolution from H2O under visible-light irradiation. The photocatalytic H2 evolution rate is 3051.4 μmol h−1 g−1 (with an apparent quantum efficiency of 4.9% at 420 nm), which is ∼2.43 times higher than that of conventional CdS nanoparticles. Furthermore, the yolk–shell CdS microcubes exhibit remarkable photocatalytic stability. This work demonstrates that MOF-derived yolk–shell structured materials hold great promise for application in the field of energy conversion.

Novel visible-light-driven Cd0.2Zn0.8S/g-C3N4 inorganic–organic composite photocatalysts were synthesized by a facile hydrothermal method. The prepared Cd0.2Zn0.8S/g-C3N4 composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible diffuse reflection spectroscopy (DRS), photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) experiments. Under visible-light irradiation, Cd0.2Zn0.8S/g-C3N4 photocatalysts displayed a higher photocatalytic activity than pure g-C3N4 and Cd0.2Zn0.8S for hydrogen evolution and degradation of pollutants, and the optimal g-C3N4 content was 20 wt%. The optimal composite showed a hydrogen evolution rate of 208.0 μmol h−1. The enhancement of the photocatalytic activity should be attributed to the well-matched band structure and intimate contact interfaces between Cd0.2Zn0.8S and g-C3N4, which lead to the effective transfer and separation of the photogenerated charge carriers. Furthermore, the Cd0.2Zn0.8S/g-C3N4 photocatalysts showed excellent stability during photocatalytic hydrogen evolution and degradation of pollutants.

In this study, a visible light responsive Cu3SnS4/reduced graphene oxide (RGO) photocatalyst has been synthesized by a facile one-step solvothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, N2 adsorption–desorption, UV–vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy. The photocatalytic activity of the Cu3SnS4/RGO composite under visible-light irradiation (λ > 420 nm) was evaluated by measuring the degradation of rhodamine B (RhB) and phenol. The results revealed that the Cu3SnS4 nanoplates dispersed uniformly on the RGO surface. The Cu3SnS4/RGO composite exhibited much higher photocatalytic activity than pure Cu3SnS4. The enhancement in photocatalytic activity is likely to be due to the synergistic effect of an improved adsorptivity of pollutants, an enhanced visible light absorption and an effective charge separation. In addition, the Cu3SnS4/RGO photocatalyst was stable during the reaction and could be used repeatedly.