Study on the Performance and Mechanism of Ag-Bi ₄ Ti ₃ O ₁₂ Composite Photocatalyst for Oxygen Production by Water Oxidation

Photocatalytic water splitting for clean energy production holds significant practical potential in addressing the global energy crisis. However, the oxygen evolution reaction (OER) remains the primary bottleneck in overall efficiency due to its kinetically sluggish and complex four-electron transfer process. Bi4Ti3O12 theoretically meets the reaction conditions of OER because of its high valence band value and unique layered structure formed by alternately stacking perovskite layers [Bi2Ti3O10]2– and bismuth oxide layers [Bi2O2]2+. However, its application in OER is limited due to its unsatisfactory charge distribution, poor separation efficiency, and low selectivity for O2. Therefore, the Ag-Bi4Ti3O12 composite photocatalyst was prepared by photodeposition. The Schottky barrier between the n-type semiconductor Bi4Ti3O12 and the noble metal Ag can be used as an effective charge transfer channel. This can alter the surface charge distribution and space charge separation efficiency of Bi4Ti3O12, prevent the selective generation of hydroxyl radicals, further enhance its product selectivity to O2, and raise Bi4Ti3O12’s OER efficiency. The results show that the OER rate of Bi4Ti3O12 after Ag loading is obviously improved, which is about twice that of unmodified Bi4Ti3O12. The research results of this work will provide research ideas for the design of efficient OER catalysts.