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Two‐dimensional (2D) materials are attractive catalysts for the electrochemical reduction of carbon dioxide reaction (eCO2RR) by virtue of their tunable atomic structures, abundant active sites, enhanced conductivity, suitable binding affinity to carbon dioxide and/or reaction intermediates, and intrinsic scalability. Herein, recent advances in 2D catalysts for the eCO2RR are reviewed. Structural features and properties of 2D materials that contribute to their advanced electrocatalytic properties are summarized, and strategies for enhancing their activity and selectivity for the eCO2RR are reviewed. Prospects and challenges of applications of 2D catalysts for the eCO2RR on an industrial scale are highlighted. [ABSTRACT FROM AUTHOR]

A simple one‐pot method has been developed to synthesize a palladium/cuprous oxide‐copper (Pd/Cu2O–Cu) material with a well‐defined structure, by modification of Cu2O–Cu with Pd through a galvanic replacement reaction. Compared with the well‐known copper/cuprous oxide (Cu/Cu2O) catalysts, the Pd/Cu2O–Cu material can catalyze the electroreduction of CO2 into C1 products with much higher faradaic efficiencies at lower overpotentials in a CO2‐saturated 0.5 m NaHCO3 solution. In particular, the highest faradaic efficiencies of 92 % for formate and 30 % for methane were achieved at −0.25 and −0.65 V (vs. the reversible hydrogen electrode), respectively. The improvement is suggested to be the result of a synergistic effect between PdH and the catalytically active copper sites during electrochemical CO2 reduction. [ABSTRACT FROM AUTHOR]

Oxides containing two‐dimensional metallic catalysts have shown enhanced catalytic activity, stability, and product selectivity. Porous three‐dimensional structures maximize the accessibility of the active sites, thus enhancing the catalytic performance of the catalysts. By integrating these desirable features in a single catalyst, further improvement in catalytic activity and selectivity is expected. In this study, oxide‐containing bismuth (Bi) nanosheets of about 4 nm thickness interconnected to form a porous three‐dimensional structure were synthesized by electrodeposition in the presence of phosphomolybdic acid under hydrogen evolution conditions. These Bi nanosheets catalyze CO2 reduction in a CO2‐saturated 0.5 m NaHCO3 solution to formate with a faradaic efficiency of 93±2 % at −0.86 V vs. RHE with a formate partial current density as high as 30 mA cm−2. The Tafel slope of about 78 mV dec−1 suggests that the protonation of the adsorbed CO2.− is the rate‐limiting step. Between the sheets: Hydrogen bubble‐templated electrodeposition of bismuth in the presence of phosphomolybdic acid leads to the formation of a three‐dimensional electrode consisting of interconnected bismuth nanosheets of 4 nm thickness. This electrode exhibits excellent catalytic activity and selectivity for CO2 reduction to formate in an aqueous bicarbonate medium. [ABSTRACT FROM AUTHOR]

The electroreduction of CO2 in the distillable ionic liquid dimethylammonium dimethylcarbamate (dimcarb) has been investigated with 17 metal electrodes. Analysis of the electrolysis products reveals that aluminum, bismuth, lead, copper, nickel, palladium, platinum, iron, molybdenum, titanium and zirconium electroreduce the available protons in dimcarb to hydrogen rather than reducing CO2. Conversely, indium, tin, zinc, silver and gold are able to catalyze the reduction of CO2 to predominantly carbon monoxide (CO) and to a lesser extent, formate ([HCOO]−). In all cases, the applied potential was found to have a minimal influence on the distribution of the reduction products. Overall, indium was found to be the best electrocatalyst for CO2 reduction in dimcarb, with faradaic efficiencies of approximately 45 % and 40 % for the generation of CO and [HCOO]−, respectively, at a potential of −1.34 V versus Cc+/0 (Cc+=cobaltocenium) employing a dimethylamine to CO2 ratio of less than 1.8:1. [ABSTRACT FROM AUTHOR]

Silver nanoclusters capped with bovine serum albumin (AgNC@BSA) were synthesized and applied for the electrocatalytic reduction of CO2. Inspired by the fact that many enzymes function only in the presence of coenzymes/cofactors that transfer electrons/protons or other groups, an electron transfer mediator was introduced to facilitate the electrical communication between the electrode and the strongly protected catalyst. The AgNC@BSA catalyst mediated by [α-SiW12O40]4− anions showed high electrocatalytic activity for CO2 reduction, which was not observed with either component on its own, in dimethylformamide containing 1 % (v/v) water. CO was the major product with excellent faradaic efficiency (>75 %). The onset potential for this catalytic CO2 reduction process is about 400 mV more positive than that found at a bulk silver electrode. This mediator-enhanced catalysis concept provides a general approach to investigate the electrocatalytic activities of nanoclusters, which remain largely unexplored. [ABSTRACT FROM AUTHOR]

Silver nanoclusters capped with bovine serum albumin (AgNC@BSA) were synthesized and applied for the electrocatalytic reduction of CO2 . Inspired by the fact that many enzymes function only in the presence of coenzymes/cofactors that transfer electrons/protons or other groups, an electron transfer mediator was introduced to facilitate the electrical communication between the electrode and the strongly protected catalyst. The AgNC@BSA catalyst mediated by [α-SiW12 O40](4-) anions showed high electrocatalytic activity for CO2 reduction, which was not observed with either component on its own, in dimethylformamide containing 1 % (v/v) water. CO was the major product with excellent faradaic efficiency (>75 %). The onset potential for this catalytic CO2 reduction process is about 400 mV more positive than that found at a bulk silver electrode. This mediator-enhanced catalysis concept provides a general approach to investigate the electrocatalytic activities of nanoclusters, which remain largely unexplored., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)