Defect Mediated Improvements in the Photoelectrochemical Activity of MoS2/SnS2 Ultrathin Sheets on Si Photocathode for Hydrogen Evolution

Anirudha Jena; Karthika Pichaimuthu; Grzegorz Leniec; Slawomir M Kaczmarek; Ho Chang; Chaochin Su; Shu-Fen Hu; Ru-Shi Liu

doi:10.1021/acsami.2c06797

Defect Mediated Improvements in the Photoelectrochemical Activity of MoS₂/SnS₂ Ultrathin Sheets on Si Photocathode for Hydrogen Evolution

ACS Appl Mater Interfaces. 2022 Sep 7;14(35):39896-39906. doi: 10.1021/acsami.2c06797. Epub 2022 Aug 26.

Authors

Anirudha Jena^{1

2}, Karthika Pichaimuthu^{1

3}, Grzegorz Leniec⁴, Slawomir M Kaczmarek⁴, Ho Chang², Chaochin Su³, Shu-Fen Hu⁵, Ru-Shi Liu¹

Affiliations

¹ Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
² Department of Mechanical Engineering and Graduate Institute of Manufacturing Technology, National Taipei University of Technology, Taipei 106, Taiwan.
³ Institute of Organic and Polymeric Materials, Research and Development Centre for Smart Textile, National Taipei University of Technology, Taipei 106, Taiwan.
⁴ Department of Technical Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology in Szczecin, al. Piastów 48, 70-311 Szczecin, Poland.
⁵ Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan.

PMID: 36018035
DOI: 10.1021/acsami.2c06797

Abstract

Solar-driven water electrolysis to produce hydrogen is one of the clean energy options for the current energy-related challenges. Si as a photocathode exhibits a large overpotential due to the slow hydrogen evolution reaction (HER) kinetics and hence needs to be modified with a cocatalyst layer. MoS₂ is a poor HER cocatalyst due to its inert basal plane. Activation of the MoS₂ basal plane will facilitate HER kinetics. In this study, we have incorporated SnS₂ into MoS₂ ultrathin sheets to induce defect formation and phase transformation. MoS₂/SnS₂ composite ultrathin sheets with a Sn²⁺ state create a large number of S vacancies on the basal sites. The optimized defect-rich MoS₂/SnS₂ ultrathin sheets decorated on surface-modified Si micro pyramids as photocathodes show a current density of -23.8 mA/cm² at 0 V with an onset potential of 0.23 V under acidic conditions, which is higher than that of the pristine MoS₂. The incorporation of SnS₂ into 2H-MoS₂ ultrathin sheets not only induces a phase but also can alter the local atomic arrangement, which in turn is verified by their magnetic response. The diamagnetic SnS₂ phase causes a decrease in symmetry and an increase in magnetic anisotropy of the Mo³⁺ ions.

Keywords: MoS2/SnS2 cocatalyst; hydrogen evolution; hydrothermal synthesis; phase transition in MoS2; photoelectrochemical water splitting; sulfur vacancies.