3D FTO/FTO-Nanocrystal/TiO2 Composite Inverse Opal Photoanode for Efficient Photoelectrochemical Water Splitting

Zhiwei Wang; Xianglin Li; Han Ling; Chiew Kei Tan; Loo Pin Yeo; Andrew Clive Grimsdale; Alfred Iing Yoong Tok

doi:10.1002/smll.201800395

3D FTO/FTO-Nanocrystal/TiO₂ Composite Inverse Opal Photoanode for Efficient Photoelectrochemical Water Splitting

Small. 2018 May;14(20):e1800395. doi: 10.1002/smll.201800395. Epub 2018 Apr 17.

Authors

Zhiwei Wang¹, Xianglin Li¹, Han Ling¹, Chiew Kei Tan¹, Loo Pin Yeo¹, Andrew Clive Grimsdale¹, Alfred Iing Yoong Tok¹

Affiliation

¹ School of Material Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.

PMID: 29665266
DOI: 10.1002/smll.201800395

Abstract

A 3D fluorine-doped SnO₂ (FTO)/FTO-nanocrystal (NC)/TiO₂ inverse opal (IO) structure is designed and fabricated as a new "host and guest" type of composite photoanode for efficient photoelectrochemical (PEC) water splitting. In this novel photoanode design, the highly conductive and porous FTO/FTO-NC IO acts as the "host" skeleton, which provides direct pathways for faster electron transport, while the conformally coated TiO₂ layer acts as the "guest" absorber layer. The unique composite IO structure is fabricated through self-assembly of colloidal spheres template, a hydrothermal method and atomic layer deposition (ALD). Owing to its large surface area and efficient charge collection, the FTO/FTO-NC/TiO₂ composite IO photoanode shows excellent photocatalytic properties for PEC water splitting. With optimized dimensions of the SnO₂ nanocrystals and the thickness of the ALD TiO₂ absorber layers, the 3D FTO/FTO-NC/TiO₂ composite IO photoanode yields a photocurrent density of 1.0 mA cm^-2 at 1.23 V versus reversible hydrogen electrode (RHE) under AM 1.5 illumination, which is four times higher than that of the FTO/TiO₂ IO reference photoanode.

Keywords: FTO/TiO2; atomic layer deposition; photoanode; photoelectrochemical water splitting.