Oxygen vacancy and pyroelectric polarization collaboratively enhancing PEC performance in BaTiO3 photoelectrodes

The efficient separation and transfer of electrons-holes is a key problem in photoelectric catalysis. Herein, oxygen vacancies are introduced into BaTiO3 and combined with pyroelectric polarization to regulate the photoelectric catalytic performance, improving the separation efficiency of carriers. Under 20–50 °C hot-cold cycle, illumination and bias, the maximum current density of BaTiO3−X-5% after oxygen vacancies introduced is 0.77 mA·cm−2, which is higher than the current density of BaTiO3 under light alone (0.17 mA·cm−2), and the current density of BaTiO3 under temperature fluctuation and light (0.35 mA·cm−2). This is because oxygen vacancies are characterized by prolonged light absorption and improved the use utilization of solar energy, it can be used as the capture center of excited electrons to inhibit excited electron-hole pairs recombination. In addition, the generation of photogenerated and pyrogenerated carriers increases the total carrier concentration, and the formation of polarized electric field promotes the separation and transfer of carriers. This offers an idea for development of high performance photoelectrodes in photoelectric catalytic water splitting.