Abstract
Titanium dioxide (TiO
2
) is the most frequently studied semiconducting material for photocatalytic water splitting. One of the favored forms of TiO
2
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 TiO
2
NS layers can be similarly grown on a Ta
2
O
5
substrate. We found that a Ta
2
O
5
back contact provides a remarkable improvement of the photocatalytic activity of the TiO
2
NSs in comparison to a FTO back contact. The TiO
2
NSs on Ta
2
O
5
exhibit a 170-fold increase in photocatalytic H
2
production rate than that obtained by TiO
2
NSs on FTO substrate. The proposed mechanism reveals that such a drastic enhancement of optimized TiO
2
NS arrays on the Ta
2
O
5
substrate is attributed to the blocking nature of Ta
2
O
5
for photo-generated electrons in the TiO
2
NSs.