Enhanced photocatalytic hydrogen evolution via the optimization of interfacial energy and mass flows

Abstract

As one of the most promising energy sources, solar energy has been utilized via photocatalysis, which has been investigated for several decades. Despite enormous efforts in photocatalyst engineering, the traditional triphasic system is still restricted by sluggish interfacial energy and mass flows, which are incompatible with the rapid reaction time of the photogenerated carriers. Herein, a biphasic photocatalytic system was constructed, in which surface carbonized wood and TiO₂ nanorods were used as the photothermal substrate material and model photocatalyst, respectively. Under concentrated solar irradiation, the designed biphasic photocatalytic system converted liquid water into gaseous water vapor for photocatalytic hydrogen evolution. In this case, the photocatalytic hydrogen evolution rate was 24.1 µmol h⁻¹, which was 4.1 times higher than that of the traditional triphasic system. The high photocatalytic activity was attributed to the photothermal coupling effect, which greatly enhanced the energy and mass flow and accelerated the photocatalytic reaction both thermodynamically and kinetically. This work provides a novel strategy for improving photocatalytic activity by optimizing energy and mass flows, which may be extended to other applications.