A drastic improvement in photocatalytic H2 production by TiO2 nanosheets grown directly on Ta2O5 substrates

Abstract

Titanium dioxide (TiO₂) is the most frequently studied semiconducting material for photocatalytic water splitting. One of the favored forms of TiO₂ for photocatalytic applications is layers of erected single-crystalline anatase nanosheets (NSs), while the most frequently reported substrate used for its synthesis is a fluorine-doped tin oxide (FTO). Herein we demonstrate that anatase TiO₂ NS layers can be similarly grown on a Ta₂O₅ substrate. We found that a Ta₂O₅ back contact provides a remarkable improvement of the photocatalytic activity of the TiO₂ NSs in comparison to a FTO back contact. The TiO₂ NSs on Ta₂O₅ exhibit a 170-fold increase in photocatalytic H₂ production rate than that obtained by TiO₂ NSs on FTO substrate. The proposed mechanism reveals that such a drastic enhancement of optimized TiO₂ NS arrays on the Ta₂O₅ substrate is attributed to the blocking nature of Ta₂O₅ for photo-generated electrons in the TiO₂ NSs.