Enhanced Charge Transport and Increased Active Sites on α-Fe₂O₃ (110) Nanorod Surface Containing Oxygen Vacancies for...

The effect of oxygen vacancies (V_O) on α-Fe₂O₃ (110) facet on the performance of photoelectrochemical (PEC) water splitting is researched by both experiments and density functional theory (DFT) calculations. The experimental results manifest that the enhancement in photocurrent density by the presence of V_O is related with increased charge separation and charge-transfer efficiencies. The electrochemical analysis reveals that the sample with V_O demonstrates an enhanced carrier density and reduced charge-transfer resistance. The results of DFT calculation indicate that the better charge separation is also contributed by the decrease of potential on the V_O surface, which improves the hole transport from the bulk to the surface. The reduced charge-transfer resistance is owing to the greatly increased number of active sites. The current study provides important insight into the roles of V_O on α-Fe₂O₃ photoanode, especially on its surface catalysis. The generated lesson is also helpful for the improvement of other PEC photoanode materials.