Boosting Photocatalytic H2 and H2O2 Evolution Enabled by Surface Non‐Uniform Pyroelectric Field Derived Dielectrophoresis Effect

A dielectrophoresis-enhanced photocatalytic system is developed to concurrently optimize charge-transfer kinetics and mass transport phenomena in photocatalytic water splitting for dual production of H₂ and H₂O₂. This platform innovatively harnesses underutilized infrared photons through the integration of dielectrophoretic effect with photocatalytic reactions, establishing a novel paradigm for synergistic energy conversion and value-added chemical synthesis.

Abstract

Photocatalytic water splitting into H₂ and H₂O₂ presents a promising approach for converting solar energy into chemical energy. However, sluggish charge migration and unsatisfactory mass transfer restrict its activity. Herein, a photocatalytic system composed of a ZnO/Mo₂C/polyacrylic acid hydrogel and carbonized wood, featuring surface non-uniform pyroelectric field-derived dielectrophoresis effect to offer a driving force for both charge and mass transfer is demonstrated. The chaotic motion of water vapor generated by the carbonized wood and the photothermal effect of Mo₂C induce surface temperature oscillations and alter the polarization state of ZnO, resulting in a maximum 0.52 V surface non-uniform pyroelectric field and stimulating a 108-fold increase in dielectrophoresis force. This photocatalytic system demonstrates a 41% reduction in carrier migration barriers induced by non-uniform pyroelectric field, alongside a local enrichment of intermediates and optimized H₂ diffusion via dielectrophoresis force, thus resulting in a record photocatalytic activity with H₂ and H₂O₂ evolution rates of 755.5 and 626.3 µmol h⁻¹, respectively. A large-area system (900 cm²) is fabricated, yielding 2.5 L of H₂ and 103.05 mmol of H₂O₂ per day under natural sunlight. This study presents promising design criteria for creating an efficient photocatalytic system focusing on energy harvesting and the production of high-value-added products.