Engineered GaN:ZnO/Carbon nanosphere heterostructure for highly efficient solar hydrogen production

초록

A GaN:ZnO/carbon nanosphere heterostructure is rationally designed for efficient solar hydrogen production. Carbon nanospheres synthesized via hydrothermal treatment of d-glucose are integrated with GaN:ZnO microparticles, fabricated through solid-state calcination and annealing, using a wet impregnation method. The optimized composite with 7.5 wt%-carbon loading achieves a remarkable hydrogen evolution rate of 14,353.7 mu mol h(-1) g(-1) under simulated solar irradiation-12.7 times higher than pristine GaN:ZnO-with a solar-to-hydrogen conversion efficiency of 0.6%. The composite also demonstrates excellent photochemical stability over five consecutive reuse cycles. The dramatic enhancement is attributed to the synergistic triple role of carbon nanospheres as broadband light absorbers, efficient electron acceptors forming a Schottky-type interface for charge separation, and active catalytic sites for proton reduction, while glycerol effectively scavenges photogenerated holes. This work establishes that strategic integration of conductive carbon nanostructures with visible-light semiconductors is a highly effective, noble-metal-free approach for engineering high-performance, durable photocatalysts for sustainable solar fuel generation.

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