Enhanced Photocatalytic CO2 Reduction Performance by External Electric Field-Driven Charge Separation on...

Traditional photoelectrocatalysis (PEC) separates photogenerated charge carriers via an external bias. However, its complex configuration and high-resistance liquid electrolytes restrict its application largely to liquid-phase systems. Taking advantage of the remarkable enhancement of the electric field gradient enabled by the interdigitated electrodes (IDEs) with a spacing of 100 µm, an external electric field-enhanced photocatalytic CO₂ reduction system was developed. A relatively high electric field strength can be generated under the application of a small external voltage. Given that the electric field strength is inversely proportional to the electrode spacing, when a 1.0 V is applied to electrodes with a 100 µm spacing, the electric field strength can reach the order of 104 V m^-1. By directly applying a modest external voltage (0.5-1.5 V) to hydrogenated TiO₂ photocatalysts, an externally induced electric field drives the directional migration of charge carriers, enhancing the separation and transport of photogenerated carriers. At 1.5 V applied voltage, the hydrogenated TK₄₅₀ catalyst achieves CH₄ and C₂H₆ production rates of 31.1 and 4.9 µmolg^-1 h^-1, represents a four-fold enhancement compared to the pristine TiO₂ baseline. Consequently, the application of this electric field-enhanced photocatalytic system to gas-phase reaction for addressing energy and environmental challenges.