Enhanced photoelectrochemical water splitting with WO3/TiO2 core/shell heterojunction photoanodes: Unveiling the role of dendritic TiO2

초록

This research presents a new approach for fabricating efficient photoanodes for water splitting by creating a core/shell heterojunction. The heterojunction consisted of vertically aligned WO3 nanoplates as the core, with a dendritic TiO2 nanoneedles array as a shell deposited onto fluorine-doped tin oxide (FTO) substrates. The WO3 nanoplates are prepared through a hydrothermal method, and the TiO2 shell is deposited using a cost-effective chemical bath deposition method. This unique architecture enhanced light absorption, promoting efficient charge separation and transport, which led to improved photoelectrochemical (PEC) performance for water splitting. The WO3/TiO2 heterojunction achieved a photocurrent density of 1.2 mA cm-2 at 1.6 V vs. RHE and demonstrated 92 % PEC stability after 3 h under simulated solar illumination (1.5 G). The enhanced performance is attributed to the favorable band alignment, which enabled efficient charge transfer between the conduction bands of TiO2 and WO3, the improved light harvesting by the WO3 nanoplates, and the excellent PEC stability of the TiO2 shell.

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