Boosting Solar Hydrogen Production of Molybdenum Tungsten Sulfide-Modified Si Micropyramids by Introducing Phosphate
Journal
ACS Applied Materials and Interfaces
Journal Volume
12
Journal Issue
37
Pages
41515-41526
Date Issued
2020
Author(s)
Abstract
Si is regarded as a promising photocathode material for solar hydrogen evolution reaction (HER) because of its small band gap and highly negative conduction band edge. However, bare Si electrodes have high overpotential because of sluggish HER kinetics on the surface. In this study, molybdenum tungsten sulfide (MoS2-WS2) was decorated on Si photocathodes as the co-catalyst to accelerate HER kinetics. The catalytic performance of MoS2-WS2 was further enhanced by introducing phosphate materials. Phosphate-modified molybdenum tungsten sulfide (PO-MoWS) was deposited on Si photoabsorbers to provide an optimal current of -15.0 mA cm-2 at 0 V. Joint characterizations of X-ray photoelectron and X-ray absorption spectroscopies demonstrated that the phosphate material dominantly coordinated with the WS2 component in PO-MoWS. Moreover, this phosphate material induced a large number of sulfur vacancies in the PO-MoWS/Si electrodes that contributed to the ideal catalytic activity. Herein, TiO2 thin films were prepared as the protective layer to improve the stability of photocathodes. The PO-MoWS/2 nm TiO2/Si electrode maintained 83.8% of the initial photocurrent after chronoamperometric measurement was performed for 8000 s. Copyright © 2020 American Chemical Society.
Subjects
molybdenum disulfide; phosphate; photoelectrochemical hydrogen production; silicon micropyramids; tungsten disulfide
SDGs
Other Subjects
Catalyst activity; Energy gap; Field emission cathodes; Hydrogen production; Hydrogen sulfide; Layered semiconductors; Molybdenum compounds; Molybdenum metallography; Oxide minerals; Photocathodes; Photocurrents; Silicon compounds; Sulfur compounds; Titanium dioxide; Tungsten metallography; X ray absorption; Catalytic performance; Conduction band edge; Optimal current; Protective layers; Solar Hydrogen Production; Sulfur vacancies; Tungsten sulfide; X-ray photoelectrons; Tungsten compounds
Type
journal article