Highly active deficient ternary sulfide photoanode for photoelectrochemical water splitting

Haiping Li,Haimei Wang,Xiang Wang,Xiuling Jiao,Yuguo Xia,Yuan Yu,Dairong Chen

doi:10.1038/s41467-020-16800-w

Haiping Li, Haimei Wang + Show 5 more

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https://doi.org/10.1038/s41467-020-16800-w

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Journal: Nature Communications	Publication Date: Jun 17, 2020
Citations: 160	License type: open-access

Affiliation: Shandong University

Abstract

The exploration of photoanode materials with high efficiency and stability is the eternal pursuit for the realization of practically solar-driven photoelectrochemical (PEC) water splitting. Here we develop a deficient ternary metal sulfide (CdIn2S4) photoanode, and its PEC performance is significantly enhanced by introducing surface sulfur vacancies, achieving a photocurrent density of 5.73 mA cm−2 at 1.23 V vs. RHE and 1 Sun with an applied bias photon-to-current efficiency of 2.49% at 0.477 V vs. RHE. The experimental characterizations and theoretical calculations highlight the enhanced effect of surface sulfur vacancies on the interfacial charge separation and transfer kinetics, which also demonstrate the restrained surface states distribution and the transformation of active sites after introducing surface sulfur vacancies. This work may inspire more excellent work on developing sulfide-based photoanodes.

Highlights

The exploration of photoanode materials with high efficiency and stability is the eternal pursuit for the realization of practically solar-driven photoelectrochemical (PEC) water splitting
The powder X-ray diffraction (PXRD) patterns of the final products are shown in Fig. 1b and all the diffractions are well indexed to cubic CdIn2S4 and FTO except for the product annealed at 550 °C, where the impurity phase of CdS appears as labeled by the asterisks
The upshift of S 2p X-ray photoelectron spectra (XPS) of Vs-CIS-500 further confirms the appearance of sulfur vacancy (Fig. 1d)[24], which is validated by the Cd 3d and In 3d peaks shifting to lower binding energy to compensate the charge nonequilibrium (Supplementary Fig. 1)

Summary

Introduction

The exploration of photoanode materials with high efficiency and stability is the eternal pursuit for the realization of practically solar-driven photoelectrochemical (PEC) water splitting. We develop a deficient ternary metal sulfide (CdIn2S4) photoanode, and its PEC performance is significantly enhanced by introducing surface sulfur vacancies, achieving a photocurrent density of 5.73 mA cm−2 at 1.23 V vs RHE and 1 Sun with an applied bias photon-to-current efficiency of 2.49% at 0.477 V vs RHE. Recent research reveals that the adjacent atoms after introducing sulfur vacancies turn into the active sites for oxygen evolution reaction (OER), which can facilitate the surface water oxidation kinetics[24]. Benefit from all these reasons, we consider that introducing sulfur vacancies into metal sulfides-based photoanodes may be an efficient strategy to improve their PEC performance. Distribution on the CdIn2S4 photoanode, which supplies an approach to adjusting the potentials at the semiconductor/electrolyte interface

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Conclusion