The intrinsic effects of oxygen vacancy and doped non-noble metal in TiO2(B) on photocatalytic oxidation VOCs by visible light driving

Constructing effective photocatalysts with visible-light-driven for degrading VOCs including formaldehyde remains a challenge. The TiO2(B) photocatalyst with a two-dimensional lamellar structure was prepared and modified by surface engineering. The DFT calculation results showed new impurity levels appeared among the energy bands of the modified TiO2(B) materials. These photocatalysts exhibited different rates of HCHO degradation under visible light. A variety of characterizations demonstrated that the surface defects greatly reduced the bandgap and enhanced the absorption of visible light. And the recombination of photogenerated electron-hole (e--h+) pairs was suppressed to varying degrees in the modulated TiO2(B) catalysts revealed in the photoelectrochemical analysis. It is necessary to match the band structure of photocatalysts with the frontier orbital of HCHO for achieving effectual photocatalytic oxidation (PCO). Remarkably, the separation and transport of photogenerated carriers were inhibited when excessive metal Cu was doped. The results in this work provide a deeper understanding of the relationship between the surface engineering of TiO2(B)-based catalysts and catalytic performance.