Rapid Fabrication of Defective CuInP₂S₆ Nanosheets for Efficient CO₂-to-Formate Conversion over Wide Current...

Electrochemical CO₂ reduction reaction (CO₂RR) to produce value-added chemicals offers a promising approach to mitigate global warming and address the energy crisis. However, the development of highly selective and durable catalysts that perform reliably across varying operational conditions remains challenging. In this work, we report the synthesis of lithium-intercalated CuInP₂S₆ (Li-CIPS) with a layered structure via a one-step chemical vapor transport method. Compared to pristine CuInP₂S₆, lithium intercalation in Li-CIPS facilitates the rapid production of ultrathin CuInP₂S₆ nanosheets through simple soaking in water. Experimental and theoretical investigations reveal that these ultrathin Li-CIPS nanosheets contain abundant sulfur vacancies (Vs), which can substantially enhance the CO₂RR activity while suppressing the competing hydrogen evolution reaction. As a result, the Li-CIPS catalyst achieves over 90% Faradaic efficiency (FE) for formate production across wide current densities ranging from 100 to 800 mA cm^-2, and it maintains stable operation over 100 h at 200 mA cm^-2. This study highlights a promising and selective AMP₂X₆-based electrocatalyst for efficient CO₂-to-formate conversion in practical applications.