Accelerating Interfacial Electron Extraction for Boosting Photocatalytic Hydrogen Evolution of Pt/Ta₃N₅:Mg+Hf

Promoting bulk charge separation in Ta3N5 through Mg doping was demonstrated as an effective strategy for enhancing photocatalytic water oxidation. However, this strategy exhibits a limited effect in addressing the long-standing issue of poor HER activity of Ta3N5. Herein, the underlying mechanism was first clarified, and a Mg–Hf codoping strategy was developed, which remarkably enhanced the HER activity. Systematic studies revealed that effective interfacial electron transfer between Ta3N5 and Pt was seriously impeded after Mg doping. UPS and DFT calculations demonstrated that Hf codoping significantly accelerates interfacial electron extraction through the modulation of Fermi level. 7.7 and 17.6 times enhancement in HER was achieved over Ta3N5:Mg+Hf as compared with Ta3N5:Mg and Ta3N5, respectively. An outstanding AQY was achieved, ranking among the highest values reported for Ta3N5. This work highlights the importance of effective interfacial electron extraction and presents a feasible approach to rationally designing Ta3N5.