Abstract
Direct electrolysis of pH-neutral seawater to generate hydrogen is an attractive approach for storing renewable energy. However, due to the anodic competition between the chlorine evolution and the oxygen evolution reaction (OER), direct seawater splitting suffers from a low current density and limited operating stability. Exploration of catalysts enabling an OER overpotential below the hypochlorite formation overpotential (≈490 mV) is critical to suppress the chloride evolution and facilitate seawater splitting. Here, a proton-adsorption-promoting strategy to increase the OER rate is reported, resulting in a promoted and more stable neutral seawater splitting. The best catalysts herein are strong-proton-adsorption (SPA) materials such as palladium-doped cobalt oxide (Co3–xPdxO4) catalysts. These achieve an OER overpotential of 370 mV at 10 mA cm−2 in pH-neutral simulated seawater, outperforming Co3O4 by a margin of 70 mV. Co3–xPdxO4 catalysts provide stable catalytic performance for 450 h at 200 mA cm−2 and 20 h at 1 A cm−2 in neutral seawater. Experimental studies and theoretical calculations suggest that the incorporation of SPA cations accelerates the rate-determining water dissociation step in neutral OER pathway, and control studies rule out the provision of additional OER sites as a main factor herein.
| Original language | English (US) |
|---|---|
| Article number | 2210057 |
| Journal | Advanced Materials |
| Volume | 35 |
| Issue number | 16 |
| DOIs | |
| State | Published - Apr 20 2023 |
Funding
N.W., P.O., S.‐F.H. contributed equally to this work. The authors acknowledge funding from the Natural Gas Innovation Fund, the Natural Sciences and Engineering Research Council (NSERC) of Canada, Qatar National Research Fund under its National Priorities Research Program award number NPRP12S‐0131‐190024, Shell Global Solutions International B.V., and the Ontario Research Fund − Research Excellence program. All DFT computations were performed on the Niagara supercomputer of the SciNet HPC Consortium. SciNet was funded by the Canada Foundation for Innovation, the Government of Ontario, the Ontario Research Fund Research Excellence Program, and the University of Toronto. N.W. and H.L. acknowledge support from the National Natural Science Foundation of China (NSFC No. 51771132) and the Thousand Youth Talents Plan of China. The authors thank S‐F.H. for XAS technical support in NSRRC. S.‐F.H. acknowledges support from the MOST funding (Contract No. MOST 110‐2113‐M‐009‐007‐MY2). The authors thank Daniel Esposito for helpful discussions and suggestions. N.W., P.O., S.-F.H. contributed equally to this work. The authors acknowledge funding from the Natural Gas Innovation Fund, the Natural Sciences and Engineering Research Council (NSERC) of Canada, Qatar National Research Fund under its National Priorities Research Program award number NPRP12S-0131-190024, Shell Global Solutions International B.V., and the Ontario Research Fund − Research Excellence program. All DFT computations were performed on the Niagara supercomputer of the SciNet HPC Consortium. SciNet was funded by the Canada Foundation for Innovation, the Government of Ontario, the Ontario Research Fund Research Excellence Program, and the University of Toronto. N.W. and H.L. acknowledge support from the National Natural Science Foundation of China (NSFC No. 51771132) and the Thousand Youth Talents Plan of China. The authors thank S-F.H. for XAS technical support in NSRRC. S.-F.H. acknowledges support from the MOST funding (Contract No. MOST 110-2113-M-009-007-MY2). The authors thank Daniel Esposito for helpful discussions and suggestions.
Keywords
- cobalt oxide
- neutral seawater splitting
- oxygen evolution reaction
- strong-proton-adsorption effect
ASJC Scopus subject areas
- General Materials Science
- Mechanics of Materials
- Mechanical Engineering
