One step synthesis and interfacial properties of black Ag/TiO2-x for enhancing sunlight absorption with application to photothermocatalytic VOCs degradation

[Display omitted] •One-step solid state calcination and reduction method was proposed.•Black Ag/TiO2-x was synthesized with close interface and enhanced charges transfer.•Ag/TiO2-x holds full spectrum respond and enhanced light absorption.•Ag/TiO2-x exhibits robust photothermal synergistic VOCs degradation performance. Titanium dioxide (TiO2) is a widely used low-cost and stable photocatalyst, but its wide bandgap and low quantum efficiency usually lead to poor photocatalytic performance. Herein, one-step solid state calcination and reduction method was proposed for simultaneously introducing surface defects and loading Ag nanoparticles (NP) on TiO2. The as-obtained black TiO2-x supported Ag NP (or Ag/TiO2-x) holds a narrow bandgap to respond to the full solar spectrum due to the presence of high concentration surface vacancies, enhanced light absorption through the surface plasmon resonance effect of Ag NP, and satisfactory photothermal effects. Moreover, such a one-step solid state synthesis method leads to closely linked interface and enhanced charges transfer between Ag NP and TiO2-x. Accordingly, Ag/TiO2-x exhibits robust photothermal synergistic VOCs degradation performance with a toluene degradation rate 6 times higher than the reference Ag/TiO2(DP) prepared by the conventional solution method.