Constructing Cu₃P Quantum Dots/Cu-Doped ZnIn₂S₄ p-n Heterojunctions for Efficient Methanol Oxidation Coupled with...

The solar-driven direct conversion of methanol to ethylene glycol, formaldehyde and simultaneous H₂ generation is an appealing strategy for converting sunlight to chemical energy. However, the low efficiency and stability of the photocatalyst remain critical bottlenecks hindering the practical implementation of this reaction. Herein, we synthesized the Cu₃P quantum dots/Cu-doped ZnIn₂S₄ p-n junction for efficient methanol oxidation and synchronous H₂ generation. The highly dispersed Cu₃P quantum dots promote electron-hole separation and furnish abundant catalytic sites. Moreover, the constructed p-n junction with a tight interface boosts the electron transfer, avoiding the serious photocorrosion of ZnIn₂S₄. Benefiting from these synergistic effects, the 2Cu₃P/Cu_0.5ZIS composite exhibits the highest photocatalytic conversion efficiency of methanol, yielding H₂, formaldehyde, and ethylene glycol with 10.34 mmol·g^-1·h^-1, 10.35 mmol·g^-1·h^-1 and 8.84 mmol·g^-1·h^-1 yields, which are 3.01, 3.05 and 3.10 times those of pure ZnIn₂S₄, respectively. A series of characterizations including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and UV-Vis diffuse reflectance spectroscopy are employed to analyze the structure, composition, and photoelectrochemical properties of the materials. This work demonstrates a novel catalyst design paradigm for the high-efficiency solar light-driven photocatalytic activation of methanol enabling the co-production of value-added C1/C2 oxygenates and clean H₂ fuel simultaneously.