TiO_2-Supported Binary Metal Oxide Catalysts for Low-temperature Selective Catalytic Reduction of NO_x with NH_3

Binary metal oxide（MnOx-A/TiO2）catalysts were prepared by adding the second metal to manganese oxides supported on titanium dioxide（TiO2）,where,A indicates Fe2O3,WO3,MoO3,and Cr2O3.Their catalytic activity,N2 selectivity,and SO2 poisonous tolerance were investigated.The catalytic performance at low temperatures decreased in the following order：Mn-W/TiO2〉Mn-Fe/TiO2〉Mn-Cr/TiO2〉Mn-Mo/TiO2,whereas the N2 selectivity decreased in the order：Mn-Fe/TiO2〉Mn-W/TiO2〉Mn-Mo/TiO2〉Mn-Cr/TiO2.In the presence of 0.01%SO2 and 6%H2O,the NOx conversions in the presence of Mn-W/TiO2,Mn-Fe/TiO2,or Mn-Mo/TiO2 maintain 98.5%,95.8%and 94.2%, respectively,after 8 h at 120°C at GHSV 12600 h？ 1 .As effective promoters,WO3 and Fe2O3 can increase N2 selectivity and the resistance to SO2 of MnOx/TiO2 significantly.The Fourier transform infrared（FTIR）spectra of NH3 over WO3 show the presence of Lewis acid sites.The results suggest that WO3 is the best promoter of MnOx/TiO2,and Mn-W/TiO2 is one of the most active catalysts for the low temperature selective catalytic reduction of NO with NH3.

Inhibiting effect of tungstic compounds on glucose hydrogenation over Ru/C catalyst

The effect of acid component including various conventional acids and tungstic compounds on glucose hydrogenation over a series of binary catalyst system containing Ru/C catalyst was investigated. The results showed that HC1, H2SO4, H3BO3, H3PO4, and HNO3 had negligible effect, while all the tungstic compounds imposed inhibiting effects on the hydrogenation of glucose over Ru/C catalyst, and the suppressing effect followed the order of H2WO4〉HPW〉WO3〉AMT〉HSiW. This order is the same as the order of ethylene glycol （EG） yields in the one-pot conversion of glucose to EG, suggesting the important role of competition between glucose hydrogenation and retro-aldol condensation in controlling the selectivity of EG.

Selective conversion of CO_(2)to CO using earth abundant tin modified copper gas diffusion electrodes

Earth-abundant copper-tin(CuSn)electrocatalysts are potential candidates for cost-effective and sustainable production of CO from electrochemical carbon dioxide reduction(eCO_(2)R).However,the requirement of highoverpotential for obtaining reasonable current,low Faradaic efficiencies(FE)and low intrinsic catalytic activities require the optimisation of the CuSn nanoarchitecture for the further advancement in the field.In the current work,we have optimised Sn loading on Cu gas diffusion electrodes(GDEs)by electrochemical spontaneous precipitation.Samples with various Sn loadings were tested in a three-chamber GDE reactor to evaluate their CO_(2)reduction performances.The best performance of 92%CO Faradaic efficiency at a cathodic current density of 120 mA cm^(-2)was obtained from the 20 min Sn deposited Cu_(2)O sample operated at-1.13 V vs.RHE.The electrocatalyst had~13%surface coverage of Sn on Cu GDE surface,and had Sn in oxide form and copper in metallic form.The catalyst also showed stable performance and was operable for>3 h under chronoamperometric conditions.The surface of the GDE reduces from Cu2O to Cu during eCO_(2)R and goes further reconstruction during the eCO_(2)R.This study demonstrates the potential of Cu-Sn for selective CO production at high current densities.

Electrochemical conversion of CO2 to syngas with a wide range of CO/H2 ratio over Ni/Fe binary single-atom catalysts

A series of carbon-based binary single-atom catalysts of Fe and Ni coordinated by nitrogen are fabricated using a glucose-chelating method.Depending on the Ni/Fe content,they exhibit a wide-range of controllable CO/H2 ratio from 0.14 to 10.86,which is meaningful to specific chemical processes.The durability of the catalyst is evaluated over an 8-hour period with no significant degradation of activity.The variation of the faradaic efficiency with Ni/Fe content is justified by density-functional-theory based calculation of the reaction barrier in both hydrogen evolution and CO2 reduction reactions.