Synergistic H2 production and tetracycline degradation: Unveiling the mechanism of a one-pot synthesized CeO2/CdS photocatalyst

Abstract

Coupling photocatalytic H₂ generation with antibiotic degradation offers a promising strategy for addressing energy and environmental challenges, leveraging the synergistic benefits of these processes. Herein, a novel heterojunction photocatalyst consisting of ultrafine CeO₂ nanoparticles anchored onto CdS nanosheets was prepared using a simple one-pot in-situ hydrothermal method, enabling the simultaneous photocatalytic H₂ generation and tetracycline (TC) degradation. The H₂ generation efficiency of the optimal CeO₂/CdS (CC-0.10) is 3544 μmol g^-1h^-1, which surpasses pure CdS by 29.3 times. Additionally, TC is degraded by CC-0.10 at a rate constant (k value) of 0.0352 min^-1, 2.73 times faster than CdS (0.0129 min^-1). The free radical quenching and electron spin resonance experiments revealed the active involvement of ^•OH and ^•O₂^- radicals in the TC degradation process. Moreover, the unique CeO₂/CdS heterojunction photocatalyst was also effective in degrading TC wastewater with an H₂ yield of 1374 μmol g^-1h^-1, displaying its dual performance in simultaneously degrading antibiotic wastewater and producing H₂. The CeO₂/CdS type II charge transfer mechanism is confirmed by XPS, EPR, KPFM, fs-TAS, and DFT calculations. This work introduces a promising approach to constructing rare-earth oxide/metal sulfide nanocomposites for addressing the interconnected challenges of energy production and environmental pollution.