Two-Dimensional Metal Coordination Polymer Derived Indium Nanosheet for Efficient Carbon Dioxide Reduction to Formate

Main group indium materials have been known as promising electrocatalysts for two-electron-involved carbon dioxide reduction to produce formate, which is a key energy vector in many industrial reactions. However, the synthesis of two-dimensional (2D) monometallic nonlayered indium remains a great challenge. Here, we present a facile electrochemical reduction strategy to transform 2D indium coordination polymer into elemental indium nanosheets. In a customized flow cell, the reconstructed metallic indium exhibits a high Faradaic efficiency (FE) of 96.3% for formate with a maximum partial current density exceeding 360 mA cm-2 and negligible degradation after 140 h operation in 1 M KOH electrocatalysts. Moreover, in and ex situ electrochemical analysis and characterizations demonstrate that the enhanced exposure of active sites and mass/charge transport at the CO2 gas-catalyst-electrolyte triple-phase interface and the restrained electrolyte flooding are contributing to producing and stabilizing carbon dioxide radical anion intermediates, thus leading to superior catalytic performance.

Automated summary

Main group indium materials are found to be efficient electrocatalysts for two-electron-involved carbon dioxide reduction to produce formate. However, the synthesis of 2D monometallic nonlayered indium remains challenging. In this study, a facile electrochemical reduction strategy is introduced to transform 2D indium coordination polymer into elemental indium nanosheets. The reconstructed metallic indium exhibits high Faradaic efficiency for formate, with excellent catalytic performance attributed to the enhanced exposure of active sites and mass/charge transport at the triple-phase interface and the restrained electrolyte flooding.