Exceptional co-catalyst free photocatalytic activities of B and Fe co-doped SrTiO3 for CO2 conversion and H2 evolution
sol-hydrothermal process, photocatalysis, charge separation, CO2 conversion, H2 evolution
ABSTRACT CO2 should be converted into chemical-fuels, and to reduce H2O to H2 over SrTiO3 (STO) owing to its negative conduction band position vs. NHE. Herein a novel B and Fe co-doped SrTiO3 (B, F-STO) photocatalyst was successfully fabricated via a single-step sol-hydrothermal process. Various experiments confirmed that B and Fe are effectively doped into the STO matrix. Boron substituted oxygen anions, while Fe substituted Ti cations. UV–visible diffuse reflectance spectra (UV–vis DRS) and valence-band X-ray photoelectron spectroscopy (XPS) spectra confirmed that the band gap of STO significantly reduced from 3.4 to 1.9 eV upon co-doping with B and Fe. Hence, the B, F-STO photocatalyst exhibits more absorption (λ ≤ 650 nm) compared to pure STO (λ ≤ 360 nm). Further, from photoluminescence spectra, fluorescence spectra, and photoelectrochemical measurements, charge separation in STO is considerably enhanced by co-doping B and Fe. This resulted in the improved UV–vis light catalytic activities for CO2 conversion to CH4 and CO and H2O splitting to evolve H2. The amounts of CH4 and CO produced over B, F-STO are ~ 17.2 and 21 μmol, respectively, about 5-fold enhanced compared to that of STO (~ 3.4 μmol CH4 and 5.2 μmol CO), and the calculated quantum efficiency at λ = 420 nm is ~ 2.16%. Similarly, the amount of H2 produced over B, F-STO is ~ 61 μmol, about 6.7-fold enhanced compared to that over STO (9 μmol), and the calculated quantum efficiency at λ = 420 nm is ~ 2.12%. This work provides feasible routes to fabricate highly efficient SrTiO3-based nanophotocatalysts for solar-fuel production.
Tsinghua University Press
Muhammad Humayun,Lei Xu,Ling Zhou,Zhiping Zheng,Qiuyun Fu,Wei Luo, Exceptional co-catalyst free photocatalytic activities of B and Fe co-doped SrTiO3 for CO2 conversion and H2 evolution. NanoRes.2018, 11(12): 6391–6404