Enhanced Photocatalytic VOCs Mineralization via Special Ga-O-H Charge Transfer Channel in α-Ga2O3/MgAl-LDH Heterojunction

Abstract

This work demonstrated a strategy of electronic structure regulation of photocatalysts to improve the charge separation and migration efficiency for optimized photocatalytic VOCs mineralization performance. A novel heterojunction of an α-Ga2O3/MgAl-LDH hexagonal system was synthesized and applied for stable photocatalytic toluene degradation. On the basis of DFT calculations and experiment results, the lattice mismatch between α-Ga2O3 and MgAl-LDH was relatively small and a charge transfer of the Ga-O-H channel was created at the interface. The channel would induce the photogenerated electrons in α-Ga2O3 and quickly transfer into MgAl-LDH, thus facilitating the charge carriers transfer and enhancing the activation of oxygen/water molecules through the electronic interaction between the catalyst surface and the adsorbent. Then, highly separated electrons and holes will, respectively, react with activated oxygen and water molecules to generate abundant reactive oxygen species. Therefore, the α-Ga2O3/MgAl-LDH hexagonal system heterojunction could achieve an excellent activity and stability of photocatalytic toluene degradation (90.71%) and mineralization (84.0%) in different relative humility, far exceeding that of P25. The atomic interfacial understanding of the heterojunction’s structure will provide a new perspective on the development of efficient photocatalysts for environmental remediation or energy conversion.