# Constructing Cu3P Quantum Dots/Cu-Doped ZnIn2S4 p-n Heterojunctions for Efficient Methanol Oxidation Coupled with Synchronous Hydrogen Generation

## TL;DR

A new photocatalyst efficiently converts methanol into useful chemicals and hydrogen using sunlight.

## Contribution

A novel Cu3P quantum dots/Cu-doped ZnIn2S4 p-n heterojunction is designed for efficient methanol oxidation and hydrogen generation.

## Key findings

- The 2Cu3P/Cu0.5ZIS composite achieves high methanol conversion efficiency with enhanced yields of H2, formaldehyde, and ethylene glycol.
- The p-n junction improves electron transfer and prevents photocorrosion of ZnIn2S4.
- Characterization techniques confirm the material's structure and photoelectrochemical properties.

## Abstract

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/Cu0.5ZIS 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.