Co-reporter:Nana Zhang, Ying Xin, Xiao Wang, Mingfen Shao, Qian Li, Xicheng Ma, Yongxin Qi, Lirong Zheng, Zhaoliang Zhang
Catalysis Communications 2017 Volume 97(Volume 97) pp:
Publication Date(Web):5 July 2017
DOI:10.1016/j.catcom.2017.04.033
•Fe-Nb composite oxides show excellent activity for NH3-SCR of NOx.•The doping of Nb into Fe2O3 improved surface areas, reducibility and acidity.•High surface areas, reducibility and acidity are responsible for activity.Iron-niobium composite oxides (NbaFeOx, a represents the mass percent of Nb in Fe-Nb composite oxides) were studied for the selective catalytic reduction (SCR) of NOx with NH3. The Nb-doped Fe2O3 was found to be responsible for the improved activity. The doping of Nb into Fe2O3 resulted in the improvement of specific surface areas, redox property and acidic amount. The optimal Nb30.3FeOx sample exhibited nearly 100% NOx conversion and N2 selectivity from 250 °C to 400 °C, which would be a promising candidate for NH3-SCR catalysts in the medium temperature ranges.Download high-res image (89KB)Download full-size image
Co-reporter:Zahid Ali Zafar;Sumair Imtiaz;Rameez Razaq;Shengnan Ji;Taizhong Huang;Yunhui Huang;James A. Anderson
Journal of Materials Chemistry A 2017 vol. 5(Issue 12) pp:5646-5660
Publication Date(Web):2017/03/21
DOI:10.1039/C7TA00282C
Rechargeable aluminum batteries (RABs) are amongst the most promising post-lithium energy storage systems (ESS) with a substantially higher specific volumetric capacity (8046 mA h cm−3), higher safety and lower cost. The development of such efficient and low cost ESSs is essential in order to meet the future energy storage demands of modern society. In recent years, a number of research articles have been reported on the evolution of cathode materials for RABs, which makes a critical review timely in order to provide inspiration for future research. This article highlights the cathode materials developed specifically for RABs, in detail, the development of carbon-based cathode materials, and then that of transition metal oxide (TMO), sulfide and chloride based cathode materials and then finally, a few other cathode materials are also discussed. Accordingly, future perspectives and opportunities are highlighted.
Co-reporter:Yaxin Chen, Guangkai Tian, Meijuan Zhou, Zhiwei Huang, Chenxi Lu, Pingping Hu, Jiayi Gao, Zhaoliang Zhang, and Xingfu Tang
Environmental Science & Technology 2016 Volume 50(Issue 11) pp:5825-5831
Publication Date(Web):April 29, 2016
DOI:10.1021/acs.est.5b06109
Emissions of particulate matters (PMs) and volatile organic compounds (VOCs) from open burning of biomass often cause severe air pollution; a viable approach is to allow biomass to burn in a furnace to collectively control these emissions, but practical control technologies for this purpose are lacking. Here, we report a hollandite manganese oxide (HMO) catalyst that can efficiently control both typical PMs and VOCs emissions from biomass burning. The results reveal that typical alkali-rich PMs such as KCl particles are disintegrated and the K+ ions are trapped in the HMO “single-walled” tunnels with a great trapping capacity. The K+-trapping HMO increases the electron density of the lattice oxygen and the redox ability, thus promoting the combustion of soot PMs and the oxidation of typical VOCs such as aldehydes and acetylates. This could pave a way to control emissions from biomass burning concomitant with its utilization for energy or heat generation.
Co-reporter:Guangkai Tian, Hui Chen, Chenxi Lu, Ying Xin, Qian Li, James A. Anderson and Zhaoliang Zhang
Catalysis Science & Technology 2016 vol. 6(Issue 12) pp:4511-4515
Publication Date(Web):05 Feb 2016
DOI:10.1039/C5CY02181B
Soot, often referred to as black carbon emitted from diesel engines, is not only a particulate matter pollutant but also a light-absorbing agent that may affect global climate, but can be effectively controlled using a catalytic diesel particulate filter (DPF). A new YBaCo4O7+δ-type oxygen storage material is reported as an effective catalyst for soot combustion. Isotopic isothermal reactions demonstrate the activation of gaseous oxygen and subsequent oxygen storage and reaction/desorption during an oxidation process. High activity and structural stability are achieved by the substitution of Co with Al and Ga to form YBa(Co0.85Al0.075Ga0.075)4O7+δ. The specific rates at 300 °C of YBaCo4O7+δ and YBa(Co0.85Al0.075Ga0.075)4O7+δ, normalized by surface areas, are an order of magnitude higher than those of CeO2-based oxides. This kind of oxygen-storage material acts as an oxygen pool, which ensures that the accumulated soot on a DPF can be promptly combusted.
Co-reporter:Changlan Wen, Xueping Gao, Taizhong Huang, Xiaoying Wu, Luping Xu, Jiemei Yu, Haitao Zhang, Zhaoliang Zhang, Jitian Han, Hao Ren
International Journal of Hydrogen Energy 2016 Volume 41(Issue 26) pp:11099-11107
Publication Date(Web):13 July 2016
DOI:10.1016/j.ijhydene.2016.05.051
•Cr2O3, which is usually adopted as ceramic material, is doped as catalyst for oxygen reduction.•Transitional metal oxide with low cost and rich sources is employed as catalysts for oxygen reduction.•4-electron style oxygen reduction reaction is observed with the catalysis of Cr2O3.Reduced graphene oxide (rGO) supported nano-chromium oxide (Cr2O3/rGO) catalyst for oxygen reduction reaction (ORR) has been successfully synthesized by the pyrolysis of chromium-urea coordination compound. The structure and morphology of the hybrid are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) tests. XRD tests reveal that the Cr2O3 with hexagonal structure is obtained. SEM and TEM tests show that the nano-Cr2O3 is supported by rGO sheet. The cyclic voltammetry, tafel, linear scanning voltammetry and current-time chronoamperometric tests prove that the obtained Cr2O3/rGO hybrid has a remarkable catalytic activity and good stability for oxygen reduction. Both the rotating disc electrode and rotating ring disc electrode tests approve that the ORR major happens through 4-electron reaction style. The Cr2O3/rGO hybrid is a promising low cost and high performances catalyst for ORR of alkaline electrolyte.
Co-reporter:Hao Li, Ying Xin, Xiao Wang, Yuhao Zhou, Qian Li and Zhaoliang Zhang
RSC Advances 2016 vol. 6(Issue 42) pp:35910-35913
Publication Date(Web):29 Mar 2016
DOI:10.1039/C6RA01622G
The chabazite-like silicoaluminophosphate molecular sieve SAPO-44 was first synthesized using tetraethylenepentamine and N,N,N′,N′-tetramethyl-1,6-hexanediamine as dual-templates. Ammonia temperature-programmed desorption profiles confirmed the presence of abundant strong acid sites due to the higher Si/Al ratio in comparison with using the routine template cyclohexane, suggesting a promising application in solid acid catalysis by SAPO-44.
Co-reporter:Sumair Imtiaz;Jian Zhang 张建;Zahid Ali Zafar;Shengnan Ji 季胜楠
Science China Materials 2016 Volume 59( Issue 5) pp:389-407
Publication Date(Web):2016 May
DOI:10.1007/s40843-016-5047-8
Biomass has been utilized as an energy source for thousands of years typically in the form of wood and charcoal. Technological advances create new methodologies to extract energy and chemicals frombiomass. The biomass-derived nanostructured porous carbons (BDNPCs) are the most promising sulfur hosts and interlayers in rechargeable lithium-sulfur (Li-S) batteries. In this article, a comprehensive review is provided in the synthesis of nanostructured porous carbon materials for high-performance rechargeable Li-S batteries by using biomass. The performances of the Li-S batteries dependent on the porous structures (micro, meso and hierarchical) from BDNPCs are discussed, which can provide an in-depth understanding and guide rational design of high-performance cathode materials by using low-cost, sustainable and natural bio-precursors. Furthermore, the current existing challenges and the future research directions for enhancing the performance of Li-S batteries by using natural biomass materials are also addressed.在人类发展的几千年中, 生物质材料被广泛应用于能源领域, 例如木材和木炭, 基于生物质材料便宜、 来源广泛、 可持续发展的优点, 采用先进的科学技术将生物质材料转换为功能化的纳米多孔碳材料, 并将其作为锂硫电池的正极材料和隔膜展现出了非常好的应用前景, 因此, 本综述介绍了以生物质为原材料制备的纳米多孔碳材料及其在锂硫电池中的应用, 并针对不同方法制备的生物质制备纳米多孔炭材料的孔结构(包括微孔、 介孔及分级孔)及其作为正极材料对于锂硫电池性能的影响进行了全面的总结, 这对合理利用生物质制备纳米多孔碳材料进一步提升锂硫电池的性能具有很好的指导作用, 最后, 本文指出了当前锂硫电池的问题及挑战, 并对进一步提升锂硫电池性能提供了有价值的观点和策略.
Co-reporter:Zhiliang Zhang, Yunzhao Fan, Ying Xin, Qian Li, Ruirui Li, James A. Anderson, and Zhaoliang Zhang
Environmental Science & Technology 2015 Volume 49(Issue 13) pp:7989
Publication Date(Web):June 5, 2015
DOI:10.1021/acs.est.5b01361
The extremely severe and persistent haze problems in some parts of the world including China have prompted the implementation of increasingly stringent tailpipe regulations. This places increasingly higher performance requirements for three-way catalysts, and in particular a widening of the air/fuel (λ) ratio operating window to facilitate operation of the on-board diagnostic system. A new pathway is presented here by tuning the nanostructure of TWCs to improve their λ activities and hydrothermal stability. High-temperature reduction and a mild-temperature reoxidation treatment for alumina-modified ceria–zirconia brought about the formation of a cubic, fully oxidized, pyrochlore-like superstructure, Ce2Zr2O8. The combination of Pd and the Ce2Zr2O8 superstructure greatly improved the λ window for Pd-only three-way catalysts. X-ray powder diffraction (XRD), temperature-programmed reduction with H2 (H2-TPR) and high-resolution transmission electron microscopy (HRTEM) characterization confirmed the interaction between Pd and the Ce2Zr2O8 superstructure, which modifies the dynamic oxygen storage capacity in comparison to the conventional Pd–Ce(Zr)O2 interaction, due to higher low-temperature reducibility for the Ce2Zr2O8 superstructure than for Ce(Zr)O2. Furthermore, the retention of the Ce2Zr2O8 superstructure derived from the interaction with Pd results in superior λ and light-off performances after hydrothermal aging treatment at 1000 °C for 12 h in air containing 10% H2O.
Co-reporter:Ying Xin, Pin Jiang, Mingqiang Yu, Huachun Gu, Qian Li and Zhaoliang Zhang
Journal of Materials Chemistry A 2014 vol. 2(Issue 18) pp:6419-6425
Publication Date(Web):06 Feb 2014
DOI:10.1039/C3TA15060G
Hierarchically ordered macro/mesoporous oxides and mixed oxides have been fabricated by adopting a dual-templating [poly(methyl methacrylate) colloidal microspheres and Pluronic P123] strategy and a wet ammonia gas infiltration–precipitation route to solidify metal precursors in situ. This is especially suitable for mixed oxides that can be prepared by a co-precipitation method using ammonia as the precipitation agent. The as-prepared Ce–Ti mixed oxides have a desirable homogeneous distribution of the components and exhibit excellent intrinsic activity for the selective catalytic reduction of NOx with NH3 under an exceptionally high gas hourly space velocity of 500000 mL g−1 h−1, which confirmed the contribution of the macropores to small-molecule reactions. Furthermore, hierarchically macro/mesoporous Mn, Cr, Ti, La, Y, Sn, Zn, Ni and Co oxides have been fabricated on a large-scale to illustrate the universal applicability of this method.
Co-reporter:Zhongpeng Wang, Xiaotong Yan, Xinlin Bi, Liguo Wang, Zhaoliang Zhang, Zheng Jiang, Tiancun Xiao, Ahmad Umar, Qiang Wang
Materials Research Bulletin 2014 51() pp: 119-127
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.12.003
Co-reporter:Yexin Zhang;Shaojie Chen;Qian Li;Jian Zhang
Science Bulletin 2014 Volume 59( Issue 31) pp:4003-4007
Publication Date(Web):2014 November
DOI:10.1007/s11434-014-0456-6
The reactions of soot with gaseous and adsorbed NO2 were tested over the K/MgAlO catalyst. After the reaction intermediates were identified by combination of in situ IR characterization and first-principles calculation, the different mechanisms were elucidated. It was found that the reactivity of adsorbed NO2 is lower than that of the gas form. The adsorbed NO2 reacts with soot in the form of nitrates, leading to the observation of two IR bands at 2,234 and 2,110 cm−1, which are ascribed to the vibration frequencies of cyanates on K sites and cyanides on the MgAlO support, respectively. On the contrary, the isocyanates were confirmed as intermediates in the reaction of soot with gaseous NO2. Because the adsorbed NO2 species (i.e., nitrates) are restricted by the electrostatic field of K+, the cyanates are produced and readily cracked into cyanides, which transfer to the MgAlO support. The gaseous NO2 favours the production of isocyanates due to their higher stability. The weaker reactivity of adsorbed NO2 at lower temperatures can be attributed to the restriction of the electrostatic field of K+.
Co-reporter:Pin Jiang;Xi Yang;Ying Xin;Yongxin Qi;Xicheng Ma
Journal of Materials Science 2013 Volume 48( Issue 6) pp:2365-2369
Publication Date(Web):2013 March
DOI:10.1007/s10853-012-7018-6
Monodisperse Fe3O4 dots with a mean size of about 2.3 nm were successfully synthesized via a polyol-hydrolysis route without adding any dispersant. Inorganic iron nitrate was used as the metal source and triethylene glycol (TEG) was used as the polyol solvent. The Fe3O4 dots were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selective area electron diffraction (SAED), Fourier transform infrared (FTIR) spectroscopy, N2 adsorption–desorption, and magnetization measurements. The as-synthesized Fe3O4 dots can not only be coagulated from the polyol by ethanol and acetone, but also easily redispersed in water by ultrasonication, resulting in a clear Tyndall effect. The obtained Fe3O4 dots exhibited superparamagnetism at room temperature and the saturation magnetization is much lower than those reported in previous works. The formation mechanism of the Fe3O4 dots was proposed to be the hydrolysis of iron nitrates and subsequent dehydration and partial reduction of Fe3+ to Fe2+ at elevated temperatures in TEG.
Co-reporter:Xiao Wang, Yexin Zhang, Qian Li, Zhongpeng Wang and Zhaoliang Zhang
Catalysis Science & Technology 2012 vol. 2(Issue 9) pp:1822-1824
Publication Date(Web):29 Jun 2012
DOI:10.1039/C2CY20353G
Active oxygen species for soot combustion with O2 on LaMnO3 were identified as O22−, O2n− (1 < n < 2) and O2m− (0 < m < 1) for the first time using in situ Raman spectroscopy during temperature-programmed oxidation (TPO) from room temperature to higher temperatures.
Co-reporter:Ping Li, Ying Xin, Qian Li, Zhongpeng Wang, Zhaoliang Zhang, and Lirong Zheng
Environmental Science & Technology 2012 Volume 46(Issue 17) pp:9600
Publication Date(Web):August 13, 2012
DOI:10.1021/es301661r
The amorphous Ce–Ti mixed oxides were reported to be catalysts for selective catalytic reduction of NOx with NH3, in which Ce and not Ti acts as their solvent in spite of the fact that Ce is low in content. The amorphous catalysts were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) equipped with selective area electron diffraction (SAED). The Ce–Ti amorphous oxide shows higher activity than its crystalline counterpart at lower temperatures. Moreover, the presence of small CeO2 crystallites as for the impregnated sample is deleterious to activity. The Ce–O–Ti short-range order species with the interaction between Ce and Ti in atomic scale was confirmed for the first time to be the active site using temperature programmed reduction with H2 (H2–TPR), in situ FTIR spectra of NO adsorption, X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine-structure (XAFS). Lastly, the Ce–O–Ti structure was directly observed by field-emission TEM (FETEM).
Co-reporter:Yexin Zhang, Xiao Wang, Zhongpeng Wang, Qian Li, Zhaoliang Zhang, and Limin Zhou
Environmental Science & Technology 2012 Volume 46(Issue 17) pp:9614
Publication Date(Web):August 13, 2012
DOI:10.1021/es302018x
The CO adsorption and subsequent reaction with preadsorbed NOx on Pd and K cosupported Mg–Al mixed oxides (Pd–K/MgAlO, 1/8/100 w/w) were investigated using in situ FTIR spectroscopy. During CO adsorption, a peculiar and well-defined IR band at 2160 cm–1 was observed. Several elaborately designed experiments such as the competitive adsorption of CO and CO2 demonstrated that the 2160 cm–1 band was exclusively assigned to a carbonyl species on K sites due to the CO spillover from Pd to K, which results from a strong Pd–K interaction based on temperature-programmed reduction with H2 experiments. Importantly, the spillover of CO is found to be involved in the reduction of preadsorbed NOx from temperature-programmed surface reactions with CO. Thus, all adsorbed NOx can be reduced by CO before desorption. Like the process of “pumping” CO by Pd from the atmosphere to “irrigate the field” of the nitrates/nitrites, the adsorbed NOx at not only K sites adjacent to Pd but also at the remote K sites can be reduced into N2 and N2O effectively.
Co-reporter:Y. Zhang;Q. Su;Q. Li;Z. Wang;X. Gao;Z. Zhang
Chemical Engineering & Technology 2011 Volume 34( Issue 11) pp:1864-1868
Publication Date(Web):
DOI:10.1002/ceat.201100291
Abstract
Soot oxidation with NO (in the absence of gas phase O2) on potassium-supported Mg-Al hydrotalcite mixed oxides (K/MgAlO) was studied using a temperature-programmed reaction and in situ FTIR techniques. Nitrite and the ketene group were identified as the reaction intermediates and thus a nitrite-ketene mechanism was proposed in which surface active oxygen on K sites of K/MgAlO is transferred to soot by NO through nitrites. In the absence of gas phase O2, soot oxidation with NO at lower temperatures (below 450 °C) is limited by the amount of active oxygen on the K sites. This kind of active oxygen is not reusable but can be replenished in the presence of gas phase O2.
Co-reporter:Ying Xin;Xi Yang;Pin Jiang; Zhaoliang Zhang; Zhongpeng Wang; Yihe Zhang
ChemCatChem 2011 Volume 3( Issue 11) pp:1772-1778
Publication Date(Web):
DOI:10.1002/cctc.201100179
Abstract
The transparent colloidal solutions of monodisperse CeO2-based quantum dots (QDs) were prepared by heating a triethylene glycol (TEG) solution of Ce(NO3)3⋅6 H2O (and Fe(NO3)3⋅9 H2O) at 180 °C. The CeO2-based QDs were characterized by X-ray powder diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), UV/vis absorption spectra and Brunauer–Emmett–Teller (BET) surface area. CeO2-based QDs with uniform particle size below 5 nm exhibit narrow size distribution, quantum effect, good re-dispersion ability and high surface area. For the formation of these QDs, a polyol-hydrolysis mechanism is proposed. CeO2 QDs are applied in fuel borne catalysts (FBCs) for diesel soot combustion, which exhibit excellent activity at a rather low temperature, owing to the homogeneous and large number of contact points between the catalyst and the soot. The doping with Fe can further improve the selectivity to CO2.
Co-reporter:Zhaoliang Zhang, Yexin Zhang, Qingyun Su, Zhongpeng Wang, Qian Li, and Xiyan Gao
Environmental Science & Technology 2010 Volume 44(Issue 21) pp:8254-8258
Publication Date(Web):October 5, 2010
DOI:10.1021/es102363f
The soot combustion with NOx and/or O2 on potassium-supported Mg−Al hydrotalcite mixed oxides under tight contact condition was studied using temperature-programmed oxidation (TPO), isothermal reaction and in situ FTIR techniques. The presence of NOx in O2 favors the soot combustion at lower temperatures (<300 °C). However, a little suppression was observed at higher temperatures (>300 °C), which was accompanied by a substantial NOx reduction. The ketene (C═C═O) and isocyanate (NCO−) species were determined as the reaction intermediates. In NOx + O2, NO2 directly interacts with the free carbon sites (C═C*) through two parallel reactions: (1) NO2 + C═C* → C═C═O + NO; (2) NO2 + C═C* → NCO− + CO2. The two reactions can proceed easily, which accounts for the promotion effect of NOx on soot combustion at lower temperatures. The further oxidation of NCO− by NO2 or O2 is responsible for the simultaneous reduction of NOx. However, the reactions between NO2 and C═C* are limited by the amount of free carbon sites, which can be provided by the oxidation of soot by O2 at higher temperatures. The interaction of NOx and catalyst results in the formation of nitrates and nitrites, which poisoned the active K sites.
Co-reporter:Ying Xin, Yongxin Qi, Xicheng Ma, Zhongpeng Wang, Zhaoliang Zhang, Shuxiang Zhang
Materials Letters 2010 Volume 64(Issue 23) pp:2659-2662
Publication Date(Web):15 December 2010
DOI:10.1016/j.matlet.2010.08.061
Rare-earth doped CeO2 solid solution nanorods were successfully prepared via a simple co-precipitation method without surfactants at room temperature and pressure. The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of the doping contents, pH values, aging times and the precipitation agents on the structure and morphology were investigated. We found that the yield and uniformity of the nanorods were significantly improved by doping with optimum contents of Nd, Sm, Eu, Gd or Y. The intrinsically anisotropic structure of the rare-earth hydroxides is the driving force for the growth of the nanorods. Raman spectra show a great increase in oxygen vacancy concentrations on the doped CeO2 solid solutions compared with that of pure CeO2.
Co-reporter:Y. Zhang;Q. Su;Z. Wang;Y. Yang;Y. Xin;D. Han;X. Yang;H. Wang;X. Gao;Z. Zhang
Chemical Engineering & Technology 2008 Volume 31( Issue 12) pp:1856-1862
Publication Date(Web):
DOI:10.1002/ceat.200800260
Abstract
The beta zeolite on cordierite ceramic monolith was synthesized by an in situ crystallization method and characterized by XRD, N2 adsorption/desorption, SEM and NH3-TPD techniques. Toluene adsorption/desorption was used as probe test for the control of cold-start emissions and treatment of volatile organic compounds. The presence of beta on the supports was confirmed by XRD, SEM, and N2 adsorption/desorption measurements. The zeolite crystals grow both into the cordierite macropores and on the surface of the monolith channels, which form an integrated network ensuring a strong adherence. The highly dispersed beta on supports, demonstrated by larger surface area and adsorption capacity of N2, resulted in a significant increase of the total acidity, and thus a greater adsorption capacity for toluene. Furthermore, it could trap larger amounts of toluene to higher temperature and show considerable activity for toluene cracking and oxidation. These are attributed to the greater acidity and stronger acid sites of in situ synthesized beta.
Co-reporter:Xin Li, Shaojie Wei, Zhaoliang Zhang, Yexin Zhang, Zhongpeng Wang, Qingyun Su, Xiyan Gao
Catalysis Today (25 October 2011) Volume 175(Issue 1) pp:112-116
Publication Date(Web):25 October 2011
DOI:10.1016/j.cattod.2011.03.057
The soot combustion on Cr-doped CeO2 mixed oxides was studied. The catalysts were characterized by X-ray powder diffraction, N2 adsorption/desorption, X-ray photoelectron spectroscopy and temperature-programmed reduction with H2. The active sites were quantified using isothermal anaerobic titrations with soot as the probe molecule. The turnover frequency (TOF) was calculated and used to evaluate the activity. The samples with a Cr/(Cr + Ce) ratio within 1–3 at.% show an improved activity on the basis of reaction rates and TOF values. The active sites were determined to be composed of Ce–O–Ce species, which is a little more active compared with CeO2 due to the promotion by the doping of Cr. Although the similar reaction rates were observed, the doping of 5 at.% Cr results in a detectable decrease of the TOF compared with CeO2. This is because the active sites are composed of Cr–O–Ce species. The strong interaction of the supported CrOx species with CeO2 results in an increase in the activity of Cr2O3. The promotional effect of Fe to CeO2 on soot combustion is more significant than that of Cr. The TOF is strongly recommended to be the basis of the activity comparison.Graphical abstractDownload high-res image (41KB)Download full-size imageHighlights► The active sites were quantified using isothermal anaerobic titrations. ► The turnover frequency (TOF) values were calculated and used to evaluate the activity. ► The doping of Cr to CeO2 (Cr/(Cr + Ce) = 1–3 at.%) results in an improved activity. ► The promotional effect of Fe to CeO2 is more significant than that of Cr.
Co-reporter:Zhaoliang Zhang, Dong Han, Shaojie Wei, Yexin Zhang
Journal of Catalysis (19 November 2010) Volume 276(Issue 1) pp:16-23
Publication Date(Web):19 November 2010
DOI:10.1016/j.jcat.2010.08.017
Fe-doped CeO2 mixed oxides were studied for soot combustion with O2 under tight contact conditions. They show increased activity compared to that of pure CeO2 and Fe2O3. The optimum Fe content according to soot ignition temperatures is Fe/(Ce + Fe) = 10 at.%. However, on the basis of turnover frequencies, the samples with a Fe/(Ce + Fe) ratio between 5 and 20 at.% show similar activity. Characterization of the catalysts and a kinetic study show that the reaction proceeds via a redox mechanism. The active sites were determined to be composed of Fe–O–Ce species, and the active oxygen was quantified using isothermal anaerobic titrations with soot as a probe molecule. The redox property for the Fe–O–Ce species is much stronger than for the Ce–O–Ce species. The methodology for quantifying active redox sites can be extended to soot combustion on all similar oxide systems.The densities of active oxygen sites and turnover frequencies for soot combustion on Fe-doped CeO2 mixed oxides are determined by isothermal anaerobic titrations with soot as the probe molecule.Download high-res image (32KB)Download full-size image
Co-reporter:Zhaoliang Zhang, Yexin Zhang, Zonggang Mu, Pengfei Yu, Xianzhi Ni, Shilong Wang, Lisheng Zheng
Applied Catalysis B: Environmental (15 November 2007) Volume 76(Issues 3–4) pp:335-347
Publication Date(Web):15 November 2007
DOI:10.1016/j.apcatb.2007.06.011
Co-reporter:Zhaoliang Zhang, Yexin Zhang, Zhongpeng Wang, Xiyan Gao
Journal of Catalysis (12 April 2010) Volume 271(Issue 1) pp:12-21
Publication Date(Web):12 April 2010
DOI:10.1016/j.jcat.2010.01.022
Potassium-promoted Mg–Al hydrotalcite mixed oxides were studied for soot combustion with O2. The significant activity was elucidated by an oxygen spillover mechanism. First, the surface-activated oxygen on K sites might spill over to the free carbon sites on soot to form a carbon–oxygen complex, ketene group, which was identified as the reaction intermediate. Then the ketene group combined with another active oxygen species to give out CO2. Two kinds of K species, Mg(Al)–O–K (tightly bound to Mg or Al) and free (isolated) K, were determined to be catalytically active sites by kinetic investigations. They could increase the reactivity and amount of surface active oxygen responsible for formation of the ketene group. The stability of K was greatly improved through the interaction with Al, which is a contribution to soot combustion of Al addition into MgO to form a K-promoted composite oxide via the hydrotalcite route.Potassium-promoted Mg–Al hydrotalcite mixed oxides were much active and stable for soot combustion. The reaction mechanism was elucidated based on turnover frequency. M stands for Mg or Al.Download high-res image (49KB)Download full-size image
Co-reporter:Xiao Wang, Yexin Zhang, Qian Li, Zhongpeng Wang and Zhaoliang Zhang
Catalysis Science & Technology (2011-Present) 2012 - vol. 2(Issue 9) pp:NaN1824-1824
Publication Date(Web):2012/06/29
DOI:10.1039/C2CY20353G
Active oxygen species for soot combustion with O2 on LaMnO3 were identified as O22−, O2n− (1 < n < 2) and O2m− (0 < m < 1) for the first time using in situ Raman spectroscopy during temperature-programmed oxidation (TPO) from room temperature to higher temperatures.
Co-reporter:Guangkai Tian, Hui Chen, Chenxi Lu, Ying Xin, Qian Li, James A. Anderson and Zhaoliang Zhang
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 12) pp:NaN4515-4515
Publication Date(Web):2016/02/05
DOI:10.1039/C5CY02181B
Soot, often referred to as black carbon emitted from diesel engines, is not only a particulate matter pollutant but also a light-absorbing agent that may affect global climate, but can be effectively controlled using a catalytic diesel particulate filter (DPF). A new YBaCo4O7+δ-type oxygen storage material is reported as an effective catalyst for soot combustion. Isotopic isothermal reactions demonstrate the activation of gaseous oxygen and subsequent oxygen storage and reaction/desorption during an oxidation process. High activity and structural stability are achieved by the substitution of Co with Al and Ga to form YBa(Co0.85Al0.075Ga0.075)4O7+δ. The specific rates at 300 °C of YBaCo4O7+δ and YBa(Co0.85Al0.075Ga0.075)4O7+δ, normalized by surface areas, are an order of magnitude higher than those of CeO2-based oxides. This kind of oxygen-storage material acts as an oxygen pool, which ensures that the accumulated soot on a DPF can be promptly combusted.
Co-reporter:Zahid Ali Zafar, Sumair Imtiaz, Rameez Razaq, Shengnan Ji, Taizhong Huang, Zhaoliang Zhang, Yunhui Huang and James A. Anderson
Journal of Materials Chemistry A 2017 - vol. 5(Issue 12) pp:NaN5660-5660
Publication Date(Web):2017/01/31
DOI:10.1039/C7TA00282C
Rechargeable aluminum batteries (RABs) are amongst the most promising post-lithium energy storage systems (ESS) with a substantially higher specific volumetric capacity (8046 mA h cm−3), higher safety and lower cost. The development of such efficient and low cost ESSs is essential in order to meet the future energy storage demands of modern society. In recent years, a number of research articles have been reported on the evolution of cathode materials for RABs, which makes a critical review timely in order to provide inspiration for future research. This article highlights the cathode materials developed specifically for RABs, in detail, the development of carbon-based cathode materials, and then that of transition metal oxide (TMO), sulfide and chloride based cathode materials and then finally, a few other cathode materials are also discussed. Accordingly, future perspectives and opportunities are highlighted.
Co-reporter:Ying Xin, Pin Jiang, Mingqiang Yu, Huachun Gu, Qian Li and Zhaoliang Zhang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 18) pp:NaN6425-6425
Publication Date(Web):2014/02/06
DOI:10.1039/C3TA15060G
Hierarchically ordered macro/mesoporous oxides and mixed oxides have been fabricated by adopting a dual-templating [poly(methyl methacrylate) colloidal microspheres and Pluronic P123] strategy and a wet ammonia gas infiltration–precipitation route to solidify metal precursors in situ. This is especially suitable for mixed oxides that can be prepared by a co-precipitation method using ammonia as the precipitation agent. The as-prepared Ce–Ti mixed oxides have a desirable homogeneous distribution of the components and exhibit excellent intrinsic activity for the selective catalytic reduction of NOx with NH3 under an exceptionally high gas hourly space velocity of 500000 mL g−1 h−1, which confirmed the contribution of the macropores to small-molecule reactions. Furthermore, hierarchically macro/mesoporous Mn, Cr, Ti, La, Y, Sn, Zn, Ni and Co oxides have been fabricated on a large-scale to illustrate the universal applicability of this method.
