Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obt...Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obtain sufficient metal-support interactions owing to the mobility of the metal precursor during evaporation drying. Here, freeze drying is applied during impregnation instead of evaporation drying for enhancing the metal-support interactions. 57 Fe ZSM-5 was chosen as a representative catalyst. A quantitative analysis was conducted based on Mossbauer spectroscopy. Compared with traditional evaporation-drying catalyst, freeze-drying catalyst has stronger metal-support interactions. In addition, more iron species are confined in the channel and smaller metal sizes and less diversity are obtained. The compositional change is also proved because of the superior performance of the freeze-drying catalyst during N2O decomposition. This method can be extended to other supported metal catalysts prepared through an impregnation method, which can be used to tune the metal-support interactions and metal sizes.展开更多
Metal atoms atomically dispersed on an inorganic metal‐based support compose a unique category of single atom catalysts(SACs)and have important applications in catalytic photoreduction reactions,including H_(2) evolu...Metal atoms atomically dispersed on an inorganic metal‐based support compose a unique category of single atom catalysts(SACs)and have important applications in catalytic photoreduction reactions,including H_(2) evolution reaction,CO_(2) reduction reaction,and N_(2) reduction reaction.In this minreview,we summarized the typical metal‐support interaction(M‐SI)patterns for successful anchoring of single‐atom metals on metallic compound supports.Subsequently,the contribution of the dispersed single metal atoms and M‐SI to photocatalytic reactions with improved activity,selectivity,and stability are highlighted,such as by accelerating charge transfer,regulating band structure of the support,acting as the reductive sites,and/or increasing catalytic selectivity.Finally,some challenges and perspectives of future development are proposed.We anticipate that this minireview will be a beneficial supplement for a comprehensive perception of metal‐based material supported SACs and their application in heterogeneous photo‐reductive catalysis.展开更多
Ordered mesoporous Mn2O3 (meso‐Mn2O3) and meso‐Mn2O3‐supported Pd, Pt, and Pd‐Pt alloy x(PdyPt)/meso‐Mn2O3; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT‐6‐templated...Ordered mesoporous Mn2O3 (meso‐Mn2O3) and meso‐Mn2O3‐supported Pd, Pt, and Pd‐Pt alloy x(PdyPt)/meso‐Mn2O3; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT‐6‐templated and poly(vinyl alcohol)‐protected reduction methods, respectively.The meso‐Mn2O3 had a high surface area, i.e., 106 m2/g, and a cubic crystal structure. Noble‐metalnanoparticles (NPs) of size 2.1?2.8 nm were uniformly dispersed on the meso‐Mn2O3 surfaces. AlloyingPd with Pt enhanced the catalytic activity in methane combustion; 1.41(Pd5.1Pt)/meso‐Mn2O3gave the best performance; T10%, T50%, and T90% (the temperatures required for achieving methaneconversions of 10%, 50%, and 90%) were 265, 345, and 425 °C, respectively, at a space velocity of20000 mL/(g?h). The effects of SO2, CO2, H2O, and NO on methane combustion over1.41(Pd5.1Pt)/meso‐Mn2O3 were also examined. We conclude that the good catalytic performance of1.41(Pd5.1Pt)/meso‐Mn2O3 is associated with its high‐quality porous structure, high adsorbed oxygen species concentration, good low‐temperature reducibility, and strong interactions between Pd‐Pt alloy NPs and the meso‐Mn2O3 support.展开更多
Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） ...Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） have a significant effect on the HM removal by clay mineral sorbents. However, the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown. To resolve this, clay mineral-rich soil column of varying composition, loaded （i） with Cu, Zn and Ni only, （ii） first with DOM followed by Cu, Zn and Ni, or （iii） with DOM, Cu, Zn and Ni simultaneously, was used in a set of desorption experiments. The soil columns were leached with 0.001 mol L-1 CaCI2 dissolved in water as control eluent and 0.001 tool L-1 CaC12 dissolved in DOM as treatment eluent. During the preceding loading phase of the sorbent, the timing of DOM addition （sequential or concurrent with HMs） was found to have a significant influence on the subsequent removal of the HMs. In particular when the column was loaded with DOM and HMs simultaneously, largely irreversible co-precipitation took place. Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM. In contrast, in manured agricultural fields （where HMs enter together with DOM）, HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.展开更多
基金supported by the Natural Science Foundation of Guangdong Province, China (5005938)Research Foundation of Education Bureau of Guangdong Province, China (2007A090302046)~~
基金Supported by the Hundred Talents Program of Chinese Academy of Sciences and the National Natural Science Foundation of China (20325620, 20773122, and 20673055)
基金supported by the National Key R&D Program of China(2016YFA0202900)the National Natural Science Foundation of China(21622606)+1 种基金Zhejiang Provincial Natural Science Foundation of China(LR18B060001)the Fundamental Research Funds for the Central Universities~~
文摘Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obtain sufficient metal-support interactions owing to the mobility of the metal precursor during evaporation drying. Here, freeze drying is applied during impregnation instead of evaporation drying for enhancing the metal-support interactions. 57 Fe ZSM-5 was chosen as a representative catalyst. A quantitative analysis was conducted based on Mossbauer spectroscopy. Compared with traditional evaporation-drying catalyst, freeze-drying catalyst has stronger metal-support interactions. In addition, more iron species are confined in the channel and smaller metal sizes and less diversity are obtained. The compositional change is also proved because of the superior performance of the freeze-drying catalyst during N2O decomposition. This method can be extended to other supported metal catalysts prepared through an impregnation method, which can be used to tune the metal-support interactions and metal sizes.
文摘Metal atoms atomically dispersed on an inorganic metal‐based support compose a unique category of single atom catalysts(SACs)and have important applications in catalytic photoreduction reactions,including H_(2) evolution reaction,CO_(2) reduction reaction,and N_(2) reduction reaction.In this minreview,we summarized the typical metal‐support interaction(M‐SI)patterns for successful anchoring of single‐atom metals on metallic compound supports.Subsequently,the contribution of the dispersed single metal atoms and M‐SI to photocatalytic reactions with improved activity,selectivity,and stability are highlighted,such as by accelerating charge transfer,regulating band structure of the support,acting as the reductive sites,and/or increasing catalytic selectivity.Finally,some challenges and perspectives of future development are proposed.We anticipate that this minireview will be a beneficial supplement for a comprehensive perception of metal‐based material supported SACs and their application in heterogeneous photo‐reductive catalysis.
基金supported by the Ph.D.Program Foundation of Ministry of Education of China(20131103110002)the NNSF of China(21377008)+2 种基金National High Technology Research and Development Program(863 Program,2015AA034603)Foundation on the Creative Research Team Con-struction Promotion Project of Beijing Municipal InstitutionsScientific Research Base Construction-Science and Technology Creation Plat-form-National Materials Research Base Construction~~
文摘Ordered mesoporous Mn2O3 (meso‐Mn2O3) and meso‐Mn2O3‐supported Pd, Pt, and Pd‐Pt alloy x(PdyPt)/meso‐Mn2O3; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT‐6‐templated and poly(vinyl alcohol)‐protected reduction methods, respectively.The meso‐Mn2O3 had a high surface area, i.e., 106 m2/g, and a cubic crystal structure. Noble‐metalnanoparticles (NPs) of size 2.1?2.8 nm were uniformly dispersed on the meso‐Mn2O3 surfaces. AlloyingPd with Pt enhanced the catalytic activity in methane combustion; 1.41(Pd5.1Pt)/meso‐Mn2O3gave the best performance; T10%, T50%, and T90% (the temperatures required for achieving methaneconversions of 10%, 50%, and 90%) were 265, 345, and 425 °C, respectively, at a space velocity of20000 mL/(g?h). The effects of SO2, CO2, H2O, and NO on methane combustion over1.41(Pd5.1Pt)/meso‐Mn2O3 were also examined. We conclude that the good catalytic performance of1.41(Pd5.1Pt)/meso‐Mn2O3 is associated with its high‐quality porous structure, high adsorbed oxygen species concentration, good low‐temperature reducibility, and strong interactions between Pd‐Pt alloy NPs and the meso‐Mn2O3 support.
基金supported by a scholarship from the Faculty of Science, University of Amsterdam, The Netherlands
文摘Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） have a significant effect on the HM removal by clay mineral sorbents. However, the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown. To resolve this, clay mineral-rich soil column of varying composition, loaded （i） with Cu, Zn and Ni only, （ii） first with DOM followed by Cu, Zn and Ni, or （iii） with DOM, Cu, Zn and Ni simultaneously, was used in a set of desorption experiments. The soil columns were leached with 0.001 mol L-1 CaCI2 dissolved in water as control eluent and 0.001 tool L-1 CaC12 dissolved in DOM as treatment eluent. During the preceding loading phase of the sorbent, the timing of DOM addition （sequential or concurrent with HMs） was found to have a significant influence on the subsequent removal of the HMs. In particular when the column was loaded with DOM and HMs simultaneously, largely irreversible co-precipitation took place. Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM. In contrast, in manured agricultural fields （where HMs enter together with DOM）, HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.
