Nitrogen doped tin oxide nanostructured catalysts for selective electrochemical reduction of carbon dioxide to formate

Tin/tin oxide materials are key electrocatalysts for selective conversion of CO2 to formate/formic acid. Herein we report a tin oxide material with nitrogen doping by using ammonia treatment at elevated temperature. The N doped material demonstrated enhanced electrocatalytic CO2 reduction activity, showing high Faradaic efficiency (90%) for formate at -0.65 V vs. RHE with partial current density of 4 mA/cm(2). The catalysis was contributed to increased electron negativity of N atom compared to O atom. Additionally, the N-doped catalyst demonstrates sulfur tolerance with retained formate selectivity. The analysis after electrolysis shows that the catalyst structure partially converts to metallic Sn, and thus the combined Sn/N-SnO2 is the key for the active CO2 catalysis. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.