Regulation of d-band center of TiO2 through fluoride doping for enhancing photocatalytic H2O2 production activity
Titanium dioxide(TiO2)has received extensive attention for photocatalytic hydrogen peroxide(H2O2)production,with the d-band center related to the adsorption performance,which affects the photocatalytic reaction process.Herein,an ingenious strategy to lower the antibonding-orbital occupancy in the Ti 3d orbital by fluoride ion(F-)doping is proposed,with density functional theory calculations predicting that F-doping into TiO2 induces a non-uniform charge distribution and ena-bles an upshift of the d-band center in F/TiO2.This manipulation provides accessible active centers with favorable d-band energy levels,which can improve the charge-transfer behavior,strengthen the interaction between the adsorbed oxygen and the photocatalyst,and reduce the adsorption energy of oxygen,eventually promoting the photocatalytic H2O2 production rate.The experimental results further confirm that a lower antibonding-orbital occupancy can intensify the adsorption of atomic oxygen at the Ti sites.Electron paramagnetic resonance experiment reveals that the pres-ence of F-ions in the lattice induces the formation of Ti3+centers that localize the extra electron needed for charge compensation.Femtosecond transient absorption(fs-TA)spectroscopy suggests that photogenerated electrons are transferred from the conduction band of F/TiO2 to the Ti3+sur-face states and surface F-ions,expediting the separation of electrons and holes.Consequently,with F-doping in TiC2,the photocatalytic H2O2 production yields improved from 277 to 467 pmol·g-1·h-1,with ethanol as a sacrificial reagent.This study provides a new strategy for regulating the d-band center to optimize the adsorption strength between the photocatalyst and oxygen atoms and achieve enhanced photocatalytic H2O2 production performance.
Antibonding orbitald-Band centerOxygen adsorptionCharge transferHydrogen peroxide production
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