Hole dynamic acceleration over CdSO nanoparticles for high-efficiency solar hydrogen production with urea photolysis

Abstract

Solar water splitting to hydrogen (H₂) fuel is considered a sustainable approach to meet green energy demands in the future, but is mainly limited owing to the sluggish hole dynamics involved in the water oxidation reaction and bulk charge separation. Herein, we implemented hole dynamics engineering over cadmium sulfide (CdS) nanoparticles (NPs) via the oxidation reaction substitution with a facile urea oxidation reaction (UOR) and surface conjugation with sulfurous groups (–S/SO_x²⁻) as hole-extraction chains, which thermodynamically reduced the reaction barrier and kinetically accelerated the charge separation concomitantly. We then demonstrated a highly efficient photocatalytic H₂ evolution reaction (HER) from a urea solution with valuable urea degradation. An impressive and stable H₂ generation rate of 1.49 mmol h⁻¹ g⁻¹ was achieved under 1 sun irradiation with an apparent quantum yield (AQY) of up to 2.4% at 420 nm. In this study, we designed CdS_xO NP photocatalysts to enable hole thermodynamic and kinetic acceleration, which promise a cost-effective and course-smooth solar H₂ production along with urea-rich wastewater purification.