Pressure regulated CO₂ electrolysis on two-dimensional Bi₂O₂Se

The electrochemical reduction of carbon dioxide (CO₂RR) offers potential for sustainable production and greenhouse gas mitigation, particularly with renewable energy integration. However, its widespread application is hindered by expensive catalysts, low selectivity, and limited current density. This study addresses these challenges by developing a low-mass-loading two-dimensional (2D) Bi₂O₂Se catalyst via chemical vapor deposition (CVD). The catalyst achieves a formate faradaic efficiency (FE) of 47.1% with a high current density of 4649 mA mg^-1 at -1.15 V (vs. RHE), significantly outperforming bulk Bi₂O₂Se. Pressurizing CO₂, a condition commonly encountered in industrial processes, further enhances formate selectivity and current density, increasing from 2189 mA mg^-1 at ambient pressure (1.01 bar) to 7457 mA mg^-1 at 40 bar. In situ Raman spectroscopy and DFT calculations reveal the intermediates and pathways involved, underscoring the critical role of pressure in regulating CO₂RR pathways. These findings highlight the potential of 2D catalysts for sustainable and industrially relevant CO₂ conversion under high pressure.