Carbon Dot-Capped Bimetallic Fe2P/MoP Phosphides for Photoelectrocatalytic Hydrogen Evolution Coupled with Ethylene Glycol Oxidation

Abstract

Photoelectrocatalytic hydrogen evolution reaction (HER) coupled with ethylene glycol oxidation reaction (EGOR) is crucial for green hydrogen production and the upcycling of waste plastics. However, its efficiency is limited by the photoelectric conversion efficiency and catalytic efficiency of photoelectrochemical electrodes. Herein, carbon dots (CDs) with strong photocatalytic activity were capped onto Fe₂P and MoP with excellent catalytic activity, and the constructed Fe₂P/MoP-CDs presented boosted photoelectric HER, EGOR, and HER//EGOR performance. Experimental results demonstrate that the lamellar structure of Fe₂P/MoP-CDs presents abundant photoelectrocatalytic active sites, appropriate visible spectrum absorption response, and energy band structure. Meanwhile, Fe₂P/MoP-CDs exhibit redox ability with a conduction band of −1.59 eV and a valence band of 1.65 eV, which is beneficial for the improved catalytic performance. These are ascribed to the reduced band gap width of Fe₂P/MoP, the improved separation and migration efficiency of photogenerated electron–hole pairs by the capped CDs, which can increase the photoelectric conversion efficiency, contributing to the improved activity and stability of photoelectrocatalysis. This work provides a strategy to develop advanced bifunctional photoelectric catalysts for HER-coupled EGOR, which helps to improve the efficiency of green hydrogen evolution and provides an effective way to upcycle waste plastic.