Synergistically constructing dual oxygen/sulfur vacancies and activating lattice oxygen in MoS2/TiO2 via heterointerface charge transfer for catalytic degradation of sulfur-containing VOCs

Catalytic degradation of sulfur-containing volatile organic compounds (S-VOCs) emitted from the natural and industrial sources has great prospects for improving the atmospheric environment. However, constructing metal sulfide-metal oxide heterointerface structure with excellent low-temperature activity and sulfur-resistance stability remains a great challenge due to the poor compatibility of lattice oxygen species with sulfur vacancies. Herein, we elaborately designed a bimetallic MoS2/TiO2 catalyst with heterointerface structure to synergistically modulate oxygen/sulfur vacancies and activate lattice oxygen for efficient degradation of methyl mercaptan (CH3SH) as representative gaseous S-VOCs, achieving complete conversion at 400 degrees C and a long-term stability over 100 h. The X-ray photoelectron spectroscopy, Raman spectra and electron paramagnetic resonance characterizations results revealed that the heterointerface electron transfer between MoS2 and TiO2 encouraged coupling catalyst to form more heterogeneous active sites. In situ DRIFTS and CH3SH-TPD characterizations confirmed that the modulation of sulfur/oxygen vacancies results in the distinct difference in the dissociation and recombination pattern of C-H bond, which significantly strengthens the adsorption and activation of CH3SH molecules, and meanwhile the activation of lattice oxygen could promote the formation of oxygenated intermediates, thus switching the reaction pathway involving sulfur vacancies to the dominant pathway involving reactive oxygen species (CH3SH conversion to CO2). Generally, this work provided a new strategy for synergistically tailoring the lattice oxygen and dual oxygen/sulfur vacancies via strong heterointerface interaction to develop more-advanced catalysts for S-VOCs catalytic decomposition.