Prompting CO2 Electroreduction to Ethanolby Iron Group Metal Ion Dopants Induced Multi-sites at the Interface of SnSe/SnSe2 p-n Heterojunction.

Abstract

The development of non-copper-based materials for CO2 electroreduction to ethanol with high selectivity at large current density is highly desirable, but still a great challenge. Herein, we report iron group metal ions of M2+ (M = Fe, Co, or Ni)-doped amorphous/crystalline SnSe/SnSe2nanorod/nanosheet hierarchical structures (a/c-SnSe/SnSe2) for selective CO2 electroreduction to ethanol. Iron group metal ions doping induces multiple active sites at the interface of M2+-doped SnSe/SnSe2 p-n heterojunction, which strengthens *CO intermediate binding for further C-C coupling to eventual ethanol generation. As a representative, Fe9.0%-a/c-SnSe/SnSe2 exhibits an ethanol Faradaic efficiency of 62.7% and a partial current density of 239.0 mA cm-2 at -0.6 V in a flow cell. Moreover, it can output an ethanol Faradaic efficiency of 63.5% and a partial current density of 201.2 mA cm-2 with a full-cell energy efficiency of 24.1% at 3.0 V in a membrane electrode assembly (MEA) electrolyzer. This work provides insight into non-Cu based catalyst design for stabilizing the key intermediates for selective ethanol production from CO2 electroreduction.