Rational Design of Silver Sulfide Nanowires for Efficient CO2 Electroreduction in Ionic Liquid

Electroreduction of CO2 holds the promise for the utilization of CO2 and the storage of intermittent renewable energy. The development of efficient catalysts for effectively converting CO, to fuels has never been more imperative. Herein, we successfully synthesized Ag2S nanowires (NWs) dominating at the facet of (121) using a modified facile one-step method and utilized them as a catalyst for electrochemical CO2 reduction reaction (CO2RR). Ag2S NWs in ionic liquid (IL) possess a partial current density of 12.37 mA cm(-2), similar to 14 and similar to 17.5-fold higher than those of Ag2S NWs and bulk Ag in KHCO3, respectively. Moreover, it shows significantly higher selectivity with a value of 92.0% at the overpotential (eta) of -0.754 V. More importantly, the CO formation begins at a low eta of 54 mV. The good performance originates from not only the presence of [EMIM-CO2](+) complexes but also the specific facet contribution. The partial density of states (PDOS) and work functions reveal that the d band center of the surface Ag atom of Ag2S(121) is closer to the Fermi energy level and has a higher d-electron density than those of Ag(111) and Ag55, which lowers transition state energy for CO2RR. Besides, density functional theory (DFT) calculations indicate that the COOH* formation over Ag2S is energetically more favorable on (111) and (121) facets than that on Ag(111) and Ag55. Therefore, we conclude that the significantly enhanced performance of Ag2S NWs in IL synergistically originates from the solvent-assisted and specific facet-promoted contributions. This distinguishes Ag2S NWs in IL as an attractive and selective platform for CO2RR