Synergistic effect of surface plasmon resonance, Ti3+ and oxygen vacancy defects on Ag/MoS2/TiO2-x ternary heterojunctions with enhancing photothermal catalysis for low-temperature wastewater degradation

Highlights: • A novel Ag/MoS₂/TiO_2-x ternary heterojunctions photocatalyst is prepared. • It narrows the bandgap and extends the photo-response from Vis to IR region. • It exhibits excellent photocatalytic and photothermal performance. • It is due to synergistic effect of SPR, Ti³⁺ and Ov defects, and heterojunction. -- Abstract: Ag/MoS₂/TiO_2-x ternary heterojunctions are fabricated through hydrothermal and photo-deposition process combine with in-situ solid-state chemical reduction approach. The prepared materials are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, photoluminescence, and X-ray photoelectron spectroscopy. The results show that the ternary heterojunctions doped with Ti³⁺ are formed, meanwhile, Ag nanoparticle and MoS₂ nanosheets are anchored on surface of TiO₂ nanobelts simultaneously. The photocatalytic degradation ratio of Bisphenol A in low temperature water and hydrogen production rate for Ag/MoS₂/TiO_2-x are up to 96.7% and ∼1.98 mmol h⁻¹ g⁻¹, respectively, which are several times higher than that of pristine TiO₂. Furthermore, the photothermal performance of Ag/MoS₂/TiO_2-x is also unexpected. The excellent photocatalytic activity and photothermal performance can be ascribed to the synergistic effect of the formation of heterojunctions, Ti³⁺ and surface oxygen vacancies defects and surface plasmon resonance of Ag nanoparticles, which extend the photoresponse to visible-infrared light region and favor the spatial separation of photogenerated charge carriers.