Abstract
Defects can strongly affect the lattice,strain,and electronic structures of nanomaterials photocatalysts,like a double-edged sword of both positive significance and negative influence on photocatalytic per-formances.To date,most studies into defects only partially elucidated their beneficial or detrimental roles in photocatalysis.However,a quantitative understanding of the photocatalytic performances modu-lated by defect concentration still needs to be discovered.Here,a series of TiO2-X mesoporous spheres(MS)with different oxygen vacancy concentrations for photocatalytic applications were prepared by high-temperature chemical reduction.The link between oxygen vacancy concentration and photocatalytic per-formance was successfully established.The localization of carriers dominated by the Stark effect is first enhanced and then weakened with increasing oxygen vacancy concentration,which is a crucial factor in explaining the double-edged sword role of defect concentration in photocatalysis.As the reduction tem-perature rises to 300 ℃,carrier localization dominated by the quantum-confined Stark effect maximizes the separation ability of photo generated electron hole pairs,thus exhibiting the best catalytic perfor-mance for photocatalytic hydrogen production and the degradation of organic pollutants,as demonstrated by a hydrogen evolution rate of 523.7 μmol g-1 h-1 and a ninefold higher RhB photodegradation rate compared to TiO2 MS.The work offers excellent flexibility for precisely constructing high-performance photocatalysts by understanding vacancy engineering.
维普
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