Herein, we report a three-dimensional porous TiO 2 /Fe 2 TiO 5 /Fe 2 O 3 (TFF) inverse opal through in situ thermal solid reactions for photoelectrochemical water splitting. The Fe 2 TiO 5 interfacial layer within TFF acting as a bridge to tightly connect to TiO 2 and Fe 2 O 3 reduces the interfacial charge transfer resistance, and suppresses the bulk carrier recombination. The optimized TFF displays a remarkable photocurrent density of 0.54 mA cm −2 at 1.23 V vs. reversible hydrogen electrode (RHE), which is 25 times higher than that of TiO 2 /Fe 2 O 3 (TF) inverse opal (0.02 mA cm −2 at 1.23 V vs. RHE). The charge transfer rate in TFF inverse opal is 2-8 times higher than that of TF in the potential range of 0.7 −1.5 V vs. RHE. The effects of the Fe 2 TiO 5 interfacial layer are further revealed by X-ray absorption spectroscopy and intensity-modulated photocurrent spectroscopy. This work offers an interfacial engineering protocol to improve charge separation and transfer for efficient solar water splitting.

Manipulating the charge carrier transport in photoactive materials is a big challenge toward high-efficient solar water splitting. Herein, we designed hierarchical ZnxCd1-xS architecture for tuning the interfacial charge transfer kinetics....

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