Beyond Metallic Electrodes: Semiconductor Photoelectrocatalysis for Organic Synthesis

Abstract Photoelectrocatalytic (PEC) systems convert incident light into photovoltage, enabling reactions to proceed at significantly reduced overpotentials. Leveraging this inherent energy efficiency, recent efforts have rapidly expanded PEC applications beyond traditional energy conversion chemistry to complex organic synthesis. Yet, current approaches often merely replicate reactions achievable with metallic electrodes rather than exhibiting intrinsically distinct reactivity. This perspective highlights that the distinct physical properties of semiconductors offer unique opportunities to control reaction pathways beyond simple energy savings. Specifically, band-edge pinning and photoresponsive behaviors are examined to elucidate the unique reaction thermodynamics and kinetics of PEC reactions. Furthermore, limitations in mechanistic studies and prospective strategies are discussed. The rational design of PEC platforms will realize reaction selectivity and efficiency unattainable by conventional electrocatalysis.