Plasmonic MoO2 coupled with sulfur-incorporated NiMoO4 as multifunctional heterostructures for solar thermoelectric self-powered urea electrolysis

Abstract

Efficient conversion and utilization of abundant renewable solar energy is highly desirable for the sustainable production of green hydrogen, but it is still a great challenge. In the present study, the multifunctional heterostructure of MoO2 coupled with sulfur-incorporated NiMoO4 (S-NiMo) on nickel foam (NF) was explored to construct a self-powered hydrogen production system that ingeniously integrates a solar thermoelectric generator (STEG) and a urea electrolyzer. The plasmonic MoO2 in S-NiMo/NF acts as a solar absorption unit to covert solar energy into thermal energy, which can combine with thermoelectric (TE) module for efficient power generation. When served as an electrocatalyst, the S-NiMo/NF exhibits excellent electrocatalytic performances to promote hydrogen evolution reaction (HER), urea oxidation reaction (UOR) and overall urea electrolysis. Under simulated solar irradiation at light intensity of 5 sun, the S-NiMo/NF-based STEG-urea electrolyzer system can produce 2.68 μmol of hydrogen per minute via the four-series connected S-NiMo/NF-STEGs. This self-powered thermoelectric urea electrolysis system offers new opportunities to convert renewable solar energy into green hydrogen.