Two-Dimensional BiPS ₄ -Derived Catalyst for the Selective Electroreduction of CO ₂ : The Synergistic Effect of Phosphorus and Sulfur along with Bismuth

Electrochemical CO 2 reduction is a promising route to produce value-added fuels and chemicals, though it is an energy-intensive technique. However, achieving high faradaic efficiency and excellent activity in a broad potential range is crucial for further use in applications such as storage batteries. In this direction, electrochemical reduction of carbon dioxide (ECO 2 RR) to formic acid with high selectivity is considered one of the promising strategies. Bismuth-based catalysts possess chances of success, with room for improvement. The present study describes the use of a two-dimensional phosphochalcogenide to construct an active catalyst for CO 2 reduction. Bismuth reconstructed from exfoliated 2D BiPS 4 nanosheets is reported for the selective reduction of CO 2 to formate. Various techniques like XPS, XRD, and in situ Raman spectroscopy reveal the transformation of the catalyst, identifying the formation of the sulfur-guided (012) facets preferentially as active sites for CO 2 reduction. A high faradaic efficiency of 92% of HCOOH is obtained at a potential of −1.2 V vs RHE in an H-type cell with high stability. Scanning electrochemical microscopy (SECM) further confirms selective formate production during the electrolysis. In situ ATR-IR measurements reveal that the *OCHO intermediate is formed during the conversion of CO 2 to formate. Due to its high efficiency and selectivity, the catalyst is further utilized as a cathode for the Zn–CO 2 battery system, and the performance and cyclability are found to be good at various current densities. These findings highlight the probability of developing bismuth-based catalysts containing sulfur and phosphorus to improve the performance of ECO 2 RR and thus mark a viable path toward good electrocatalysts.