We report an amino-functionalized indium-organic framework for efficient CO2 reduction to formate. The immobilized amino groups strengthen the absorption and activation of CO2 and stabilize the active intermediates, which endow an enhanced catalytic conversion to formate despite the inevitable reduction and reconstruction of the functionalized indium-based catalyst during electrocatalysis. The reconstructed amino-functionalized indium-based catalyst demonstrates a high Faradaic efficiency of 94.4 % and a partial current density of 108 mA cm-2 at -1.1 V vs. RHE in a liquid-phase flow cell, and also delivers an enhanced current density of ca. 800 mA cm-2 at 3.4 V for the formate production in a gas-phase flow cell configuration. This work not only provides a molecular functionalization and assembling concept of hybrid electrocatalysts but also offers valuable understandings in electrocatalyst evolution and reactor optimization for CO2 electrocatalysis and beyond.
Keywords: CO2 reduction; electrocatalysts; formate; functionalization; metal-organic frameworks.
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