Cationic vacancy engineering of p-TiO₂ for enhanced photocatalytic nitrogen fixation

Defect engineering is one of the effective strategies to regulate and control catalyst properties. Constructing appropriate catalytically active centers effectively tunes the electronic and surface properties of the catalyst to achieve further enrichment of photogenerated electrons, enhances the electronic feedback of the catalytically active center to the anti-bonding orbitals of the nitrogen molecule, and enhances N₂ adsorption while weakening the NN bond. In this study, titanium vacancy (V_Ti)-rich undoped anatase p-TiO₂ was successfully synthesized to investigate the effect of its metal vacancies on photocatalytic nitrogen reduction reaction (NRR) performance. The cation vacancies of V_Ti-rich p-TiO₂ lead to local charge defects that enhance carrier separation and transport while trapping electrons to activate N₂, allowing effective reduction of the excited electrons to NH₃. This work provides a viable strategy for driving the efficiency of photocatalytic nitrogen fixation processes by altering the structural properties of semiconductors through cationic vacancies, offering new opportunities and challenges for the design and preparation of titanium dioxide-based materials.