Increasing the Hot‐Electron Driven Hydrogen Evolution Reaction Rate on a Metal‐Free Graphene Electrode
Abstract
Recently, it has been shown that a semiconductor–insulator–graphene device can drive the hydrogen evolution reaction (HER) at the graphene surface with a reduced onset potential by injecting hot electrons into graphene. However, the catalytic properties of graphene are limited by the large hydrogen adsorption energy and lack of electrochemically active sites. To address these limitations, a n‐silicon/insulator/plasma etched graphene device is investigated, where a dry etch process is used to increase the number of active sites on the graphene by creating a greater number of active edge sites, increasing hydrogen adsorption at a given potential. This has been shown to improve the properties of devices with cold electrons. However, here it is shown that this approach can improve the HER rate with hot electrons. The electrons injected into the graphene from the silicon shift the onset potential of HER by as high as ≈0.8 V reaching a current density of 90 mA cm−2 at an overpotential of ‐0.5 V versus RHE. Furthermore, the comparison between device with pristine graphene shows a ≈2X improvement in current density at high overpotentials. This result shows that hot‐electron devices can be improved by modifying the catalytically active sites without metal catalysts.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 08, 2021
- Source ID
- 10.1002/admi.202001706
Entities
People
- Hyun Uk Chae
- Jun Tao
- Ragib Ahsan
- Rehan Kapadia
- Stephen B Cronin
Organizations
- Air Force Office of Scientific Research
- Army Research Office
- Lawrence Berkeley National Laboratory
- National Science Foundation
- Office of Basic Energy Sciences
- Office of Science
- United States Department of Energy
- University of Southern California