CeO2-supported Fe,Co and Ni toward CO2 hydrogenation: Tuning catalytic performance via metal-support interaction

The chemical transformation of CO₂ produces carbon compounds that can be used as precursors for the production of chemicals and fuels.Here,we investigated the activity and selectivity of the transition metals(Fe,Co,and Ni) supported on CeO₂ catalyst for CO₂ hydrogenation at atmospheric pressure.We found that Ni/CeO₂ shows the highest CO₂ conversion compared with Fe/CeO₂ and Co/CeO₂.Besides,Co/CeO₂ and Ni/CeO<...     

Sol-Gel Synthesis of LaMO3 (M = Cr, Mn, Fe, Co, Ni) Nanocrystalline Powders

Sol-gel synthesis of LaMO3 ( M = Cr, Mn, Fe, Co, Ni) nanocrystalline Powders was investigated. DSC measurement shows that precursors decomposed at about 403 K and 620 K to bum out of N, C, and H. The calcined samples at 1073 K were determined by XRD to be single phase. SEM observation shows that the prepared samples are nanocrystalline powders in broad sense. The average grain size of LaM'O3 (M'= Cr, Mn, Fe, Ni) is 150 ～700 nm,and the grain size of LaCoO3 is about 30 nm.     

Structure and Redox Properties of VCe0.95M0.05（M=Cu,Co,Mn,Fe and Cr）Mixed Oxides

Ｖａｎａｄｉｕｍｏｘｉｄｅｈａｓｂｅｅｎｗｉｄｅｌｙｓｔｕｄｉｅｄｉｎｔｈｅｒｅｃｅｎｔｙｅａｒｓｂｅｃａｕｓｅｏｆｉｔｓｉｍｐｏｒｔａｎｃｅｉｎｍａｎｙａｒｅａｓｏｆｃｈｅｍｉｓｔｒｙ .Ｉｎｔｈｅａｒｅａｏｆｃａｔａｌｙ ｓｉｓ ,ｖａｎａｄｉｕｍｏｘｉｄｅｈａｓｂｅｅｎｕｓｅｄａｓａｃａｔａ ｌｙｓｔｆｏｒｓｅｌｅｃｔｉｖｅｏｘｉｄａｔｉｏｎ ,ｏｘｉｄａｔｉｖｅｄｅｈｙｄｒｏ ｇｅｎａｔｉｏｎ ,ａｎｄａｍｍｏｘｉｄａｔｉｏｎｒｅａｃｔｉｏｎ[1～ 4] .Ｉｎｔｈｅｏｘｉｄａｔｉｏｎｒｅａｃｔｉｏｎｏｎ…     

Structure formation in binary Al-TM (TM = Mn,Co, Ni,Cu) melts

The structures of binary Al-TM (transition metal TM = Mn, Co, Ni, Cu) melts at near-liquidus temperatures are studied by X-ray diffraction and simulation using the reverse Monte Carlo method. The melts are found to have chemical local atomic ordering, and this ordering depends on the nature and content of TM. Chemical local atomic ordering leads to a medium-range order as a result of TM atom localization at distances of 0.4–0.5 nm in the composition of polytetrahedral clusters having icosahedral symmetry. A medium-range order in the melts is identified due to the presence of an additional maximum (prepeak) in the left slope of the first peak in experimental structure factor curves. The local atomic orders in the melts and the corresponding crystalline and quasicrystalline phases are found to correlate with each other.     

湿法冶金(包括Zn、Mn、Cu、Ni、Co等)除铁的几种主要方法

论述了湿法冶金除铁的几种主要方法,包括中和水解法、黄钾铁矶法与针铁矿法除铁的化学反应、热力学分析及技术条件等.     

Effects of water on CO catalytic oxidation over Pd/CeO_2

The role of water in CO oxidation was investigated on Pd/CeO_2 with different morphologies(rods(R),cubes(C) and octahedrons(O)).Compared with the absence of water,CO oxidation activity increases 2 times in the presence of water on Pd/CeO_2-C;but a decrease is found on Pd/CeO_2-R.Catalyst characterization reveals that Pd is mainly in the form of solid solution(Pd_xCe_(1-x)O_(2-σ)) on Pd/CeO_2-R and a mixture of metal and Pd_xCe_(1-x)O_(2-σ) solid solution on Pd/CeO_2-C.The strong interaction between Pd and CeO_2-R results in the form of stable bidentate carbonates species;while the relatively weak interaction between Pd and CeO_2-C leads to the produce of unstable monodentate carbonates species.The effects of water on CO oxidation activity closely relate with the Pd chemical state and the types of carbonates species.Water restrains CO adsorption on Pd_xCe_(1-x)O_(2-σ) solid solution,but it has negligent effects on metallic Pd species.In the presence of water,bidentate carbonates species remains stable but the decrease in the amount of monodentate carbonates species is observed.     

Synergistic effects of CeO2/Cu2O on CO catalytic oxidation: Electronic interaction and oxygen defect

For CO catalytic oxidation, Cu and Ce species are of great importance, between which the synergistic effect is worth investigating. In this work, CeO₂/Cu₂O with Cu₂O {111} and {100} planes were comparatively explored on CO catalytic oxidation to reveal the effects of interfacial electronic interactions and oxygen defects. The activity result demonstrates that CeO₂/o-Cu₂O {111} has superior performance compared with CeO₂/c-Cu₂O {100}. Credit to the coordination unsaturated copper atoms (Cu_CUS) on o-Cu₂O {111} surface, the interfacial electronic interactions on CeO₂/o-Cu₂O {111} are more obvious than those on CeO₂/c-Cu₂O {100}, leading to richer oxygen defect generation, better redox and activation abilities of CO and O₂ reactants. Furthermore, the reaction mechanism of CeO₂/o-Cu₂O {111} on CO oxidation is revealed, i.e., CO and O₂ are adsorbed on the Cu_CUS on Cu₂O {111} and oxygen defect of CeO₂, respectively, and then synergistically promote the CO oxidation to CO₂. The work sheds light on the designing optimized ceria and copper-based catalysts and the mechanism of CO oxidation.     

Preparation,characterization and catalytic oxidation property of CeO2/Cu2+- attapulgite (ATP) nanocomposites

Cerium oxide (CeO₂) coated on copper modified attapulgite clay nanocomoposite (CeO₂/Cu²⁺-ATP) was prepared by homogeneous deposition method. The microstructures of the as-prepared CeO₂/Cu²⁺-ATP nanocomposites were characterized by X-ray diffraction (XRD), energy-dispersive spectrometer (EDS) and transmission electron microscopy (TEM). The results indicated that CeO₂ particles with average size of about 5 nm were loaded onto the Cu²⁺-ATP and were widely dispersed. Comparing the catalytic activity of ATP/CeO₂ and CeO₂/Cu²⁺-ATP, the catalytic activity was improved when a small quantity of Cu²⁺ was introduced. The loading amount of CeO₂ and reaction temperature had important effects on decolorization ratio of methyl orange (MO). When the loading amount and reaction temperature were 70% and 338 K, respectively, the decolorization ratio of MO reached over 99%, which showed excellent catalytic activity.     

Effects of different alloying elements M (M =Fe,Ni,Mn,Si,Mo,Cu,Y)on Cr2O3 with Cl:a first-principles study

Using the first-principles methods,the effects of different alloying elements M (M =Fe,Ni,Mn,Si,Mo,Cu,Y) on Cr2O3 with C1 adsorption are studied.The results sho...