Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with differ...Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with different compositions and configurations, it is proposed that acetic acid is predominantly produced via an intermediate of acetaldehyde. This can be easily confirmed by comparing the product distributions in the integral and the differential reactors. The active sites for acetic acid formation are considered to exist mainly at the boundaries between the H4SiW12O40 and the Pd particles. The Pd-based catalysts reduced by H2/N2 have higher activities than those reduced by hydrazine, as explained by the degree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption. It was found that the Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than that with potassium selenite, and that the acetic acid yield can be greatly increased by adding a suitable amount of dichloroethane (C2H4C12/C2H4 mole ratio=0.03) to the reactants.展开更多
Upgrading of atmospheric CO_(2) into high-value-added acetate using renewable electricity via electrocatalysis solely remains a great challenge.Here,inspired by microbial synthesis via biocatalysts,we present a couple...Upgrading of atmospheric CO_(2) into high-value-added acetate using renewable electricity via electrocatalysis solely remains a great challenge.Here,inspired by microbial synthesis via biocatalysts,we present a coupled system to produce acetate from CO_(2) by bridging inorganic electrocatalysis with microbial synthesis through formate intermediates.A 3D Bi_(2)O_(3)@CF integrated electrode with an ice-sugar gourd shape was fabricated via a straightforward hydrothermal synthesis strategy,wherein Bi_(2)O_(3) microspheres were decorated on carbon fibers.This ice-sugar gourd-shaped architecture endows electrodes with multiple structural advantages,including synergistic contribution,high mass transport capability,high structural stability,and large surface area.Consequently,the resultant Bi_(2)O_(3)@CF exhibited a maximum Faradic efficiency of 92.4%at−1.23 V versus Ag/AgCl for formate generation in 0.5 M KHCO_(3),exceeding that of Bi_(2)O_(3)/CF prepared using a conventional electrode preparation strategy.Benefiting from the high formate selectivity,unique architecture,and good biocompatibility,the Bi_(2)O_(3)@CF electrode attached with enriched CO_(2)-fixing electroautotrophs served as a biocathode.As a result,a considerable acetate yield rate of 0.269±0.009 g L^(−1) day^(−1)(a total acetate yield of 3.77±0.12 g L^(−1) during 14-day operation)was achieved in the electrochemical–microbial system equipped with Bi_(2)O_(3)@CF.展开更多
文摘Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with different compositions and configurations, it is proposed that acetic acid is predominantly produced via an intermediate of acetaldehyde. This can be easily confirmed by comparing the product distributions in the integral and the differential reactors. The active sites for acetic acid formation are considered to exist mainly at the boundaries between the H4SiW12O40 and the Pd particles. The Pd-based catalysts reduced by H2/N2 have higher activities than those reduced by hydrazine, as explained by the degree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption. It was found that the Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than that with potassium selenite, and that the acetic acid yield can be greatly increased by adding a suitable amount of dichloroethane (C2H4C12/C2H4 mole ratio=0.03) to the reactants.
基金National Key Research and Development Program of China,Grant/Award Number:2018YFA0901300National Natural Science Foundation of China,Grant/Award Numbers:21975124,52173173,21603209+1 种基金the Natural Science Foundation of Jiangsu Province,Grant/Award Numbers:BK20220051,BK20220002Jiangsu Province Carbon Peak and Neutrality Innovation Program,Grant/Award Numbers:BE2022002-3,BE2022031-4。
文摘Upgrading of atmospheric CO_(2) into high-value-added acetate using renewable electricity via electrocatalysis solely remains a great challenge.Here,inspired by microbial synthesis via biocatalysts,we present a coupled system to produce acetate from CO_(2) by bridging inorganic electrocatalysis with microbial synthesis through formate intermediates.A 3D Bi_(2)O_(3)@CF integrated electrode with an ice-sugar gourd shape was fabricated via a straightforward hydrothermal synthesis strategy,wherein Bi_(2)O_(3) microspheres were decorated on carbon fibers.This ice-sugar gourd-shaped architecture endows electrodes with multiple structural advantages,including synergistic contribution,high mass transport capability,high structural stability,and large surface area.Consequently,the resultant Bi_(2)O_(3)@CF exhibited a maximum Faradic efficiency of 92.4%at−1.23 V versus Ag/AgCl for formate generation in 0.5 M KHCO_(3),exceeding that of Bi_(2)O_(3)/CF prepared using a conventional electrode preparation strategy.Benefiting from the high formate selectivity,unique architecture,and good biocompatibility,the Bi_(2)O_(3)@CF electrode attached with enriched CO_(2)-fixing electroautotrophs served as a biocathode.As a result,a considerable acetate yield rate of 0.269±0.009 g L^(−1) day^(−1)(a total acetate yield of 3.77±0.12 g L^(−1) during 14-day operation)was achieved in the electrochemical–microbial system equipped with Bi_(2)O_(3)@CF.
