Abstract
Proton exchange membrane electrolyzer cells (PEMECs) have received great attention for hydrogen/oxygen production due to their high efficiencies even at low-temperature operation. Because of the high cost of noble platinum-group metal (PGM) catalysts (Ir, Ru, Pt, etc.) that are widely used in water splitting, a PEMEC with low catalyst loadings and high catalyst utilizations is strongly desired for its wide commercialization. In this study, the ultrafast and multiscale hydrogen evolution reaction (HER) phenomena in an operating PEMEC is in-situ observed for the first time. The visualization results reveal that the HER and hydrogen bubble nucleation mainly occur on catalyst layers at the rim of the pores of the thin/tunable liquid/gas diffusion layers (TT-LGDLs). This indicates that the catalyst material of the conventional catalyst-coated membrane (CCM) that is located in the middle area of the LGDL pore is underutilized/inactive. Based on this discovery, a novel thin and tunable gas diffusion electrode (GDE) with a Pt catalyst thickness of 15 nm and a total thickness of about 25 µm has been proposed and developed by taking advantage of advanced micro/nano manufacturing. The novel thin GDEs are comprehensively characterized both ex-situ and in-situ, and exhibit excellent PEMEC performance. More importantly, they achieve catalyst mass activity of up to 58 times higher than conventional CCM at 1.6 V under the operating conditions of 80 °C and 1 atm. This study demonstrates a promising concept for PEMEC electrode development, and provides a direction of future catalyst designs and fabrications for electrochemical devices.
Original language | English |
---|---|
Pages (from-to) | 434-441 |
Number of pages | 8 |
Journal | Nano Energy |
Volume | 47 |
DOIs | |
State | Published - May 2018 |
Funding
The authors greatly appreciate the support from U.S. Department of Energy's National Energy Technology Laboratory under Award DE-FE0011585 and National Renewable Energy Laboratory under Award DE-AC36-08GO28308 . This research was partially conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. The authors also wish to express their appreciation to Dr. Bo Han, William Barnhill, Dale Hensley, Dayrl Briggs, Alexander Terekhov, Douglas Warnberg, and Kate Lansford for their help. Appendix A
Funders | Funder number |
---|---|
DOE Office of Science user facility | |
U.S. Department of Energy | DE-FE0011585 |
National Renewable Energy Laboratory | DE-AC36-08GO28308 |
Keywords
- High catalyst mass activity
- Hydrogen evolution reaction
- Proton exchange membrane electrolyzer cell
- Thin gas diffusion electrode
- Ultra-low catalyst loading