High photoelectrochemical response of SrTiO3/TiO2/TiN films synthesized via hydrothermal-galvanic couple method with reductive annealing
摘要
Heterostructures have been extensively employed to enhance charge separation and improve performance in photoelectrochemical (PEC) systems. In this study, SrTiO3/TiO2/TiN heterostructured films were synthesized via a straightforward hydrothermal-galvanic couple (HT-GC) method, followed by annealing under controlled atmospheres with varying nitrogen and oxygen partial pressures. Conductive TiN seed layers were deposited using a facile, air-based sputtering technique, and granular SrTiO3 films were subsequently grown through the HT-GC process. Post-annealing produced well-defined SrTiO3/TiO2/TiN heterostructures. Films annealed in reductive N2/H2 at 900 °C exhibited the highest photocurrent density of 7.2 ± 0.4 mA/cm2, surpassing previously reported SrTiO3/TiO2 systems. This enhancement is attributed to the formation of large-grained TiO2 both between SrTiO3 grains and at the SrTiO3/TiN interface, generating abundant SrTiO3/TiO2 heterointerfaces, along with the introduction of oxygen vacancies. These features promote efficient charge separation and suppress recombination. The TiN underlayer also contributes to the improved PEC response via plasmonic effects and high-quality interfaces. This work demonstrates a facile strategy for engineering oxygen-vacancy-rich heterostructures, advancing their potential for PEC applications.