Enhanced photocatalytic CO2 reduction performance of PbTiO3 via oxygen vacancy engineering and electronic state modulation

In the field of photocatalytic conversion, the efficiency of charge separation between photogenerated electrons and holes is a critical determinant of catalytic performance. However, the development of highly efficient photocatalysts and the precise modulation of their electronic orbitals remain significant challenges. In this study, PbTiO 3 powder was first successfully synthesized via the high-temperature solid-state method. Subsequently, surface oxygen vacancies were introduced through a hydrothermal acid-induced treatment. Experimental results demonstrate that the PbTiO 3 sample with the highest concentration of oxygen vacancies exhibits significantly enhanced photocatalytic performance, achieving a 19-fold increase in activity compared to pristine PbTiO 3 . The CO evolution rate reaches 16.26 μmol·g −1 ·h −1 , with a selectivity of 92.71%. A comprehensive investigation into the underlying mechanism reveals three key contributing factors. First, the abundant formation of oxygen vacancies provides a high density of active sites for CO 2 adsorption and activation, thereby promoting the catalytic reaction; Second, the reduced band gap width facilitates the generation of photogenerated electron-hole pairs by lowering the energy threshold for electronic transitions, thereby improving charge carrier generation and electron transport efficiency. Third, in PbTiO 3 , electrons are transferred from titanium to oxygen atoms, accompanied by electron filling from the t 2g to the e g orbitals of oxygen. This results in increased electron density in the e g orbitals, which enhances the capacity of oxygen vacancies to capture electrons. Therefore, the modulation of the electronic state significantly enhances the separation efficiency of photogenerated electron-hole pairs. Based on the aforementioned optimization strategies, this study offers novel insights and methodologies for the design of efficient photocatalytic systems with orbital regulation capabilities, and holds promise for advancing the broader application and development of photocatalytic technologies in areas such as energy conversion and environmental remediation.