Synergic Delocalized‐Conjugate and Electron‐Deficient Effect and Mesoporous Channel Promote Photocatalytic Coupling H2 Evolution with Benzyl‐Alcohol Oxidation

Abstract

AbstractPhotocatalytic merging H2 evolution with benzyl‐alcohol (BA) oxidation offers a promising approach to producing H2 and value‐added chemicals due to water photocatalysis with a sluggish kinetic process and gas‐mixed H2/O2 gas security concern. Herein, incorporating electron‐deficient pyromellitic dianhydride into large π‐conjugate polymeric carbon nitride builds an effective in‐electric field (IEF). The resultant photocatalyst shows the dependence on the ratio of H2O and BA for H2 and benzaldehyde production, particularly the highest yield rate of H2 (13.87) and benzaldehyde (7.71 mmol h−1 g−1), 69.2% at 400 nm of internal quantum efficiency for H2‐evolution, and 2.15% of solar‐to‐hydrogen efficiency under simulated AM 1.5G irradiation. Mechanism analysis suggests that the strong driving force of effective IEF originates from the cooperating large delocalized π‐conjugate and electron‐deficient effect, which overwhelms the intrinsic binding energy of charge carrier to enhance its separation and migration efficiency dramatically. Moreover, extended light response and mesoporous channel in photocatalyst improve the absorption edge and tail, the n→π* transition, and mass transport of BA. In situ characterizations revealed that the enhanced H2 production is due to the releasing protons from BA oxidation via carbon‐centered radical‐mediated. These findings provide a novel strategy and deep understanding of photocatalytic coupling H2 with added‐value chemical production.