Strong‐Proton‐Adsorption Co‐Based Electrocatalysts Achieve Active and Stable Neutral Seawater Splitting. Issue 16 (15th March 2023)

• Record Type: Journal Article
• Authors: Wang, Ning; Ou, Pengfei; Hung, Sung‐Fu; Huang, Jianan Erick; Ozden, Adnan; Abed, Jehad; Grigioni, Ivan; Chen, Clark; Miao, Rui Kai; Yan, Yu; Zhang, Jinqiang; Wang, Ziyun; Dorakhan, Roham; Badreldin, Ahmed; Abdel‐Wahab, Ahmed; Sinton, David; Liu, Yongchang; Liang, Hongyan; Sargent, Edward H.
• Is Part Of: Advanced materials. Volume 35:Issue 16(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-15
• Subjects: cobalt oxide -- neutral seawater splitting -- oxygen evolution reaction -- strong‐proton‐adsorption effect; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202210057
• Languages: English
• ISSNs: 0935-9648

Abstract

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– x Pd x O4 ) catalysts. These achieve an OER overpotential of 370 mV at 10 mA cm −2 in pH‐neutral simulated seawater, outperforming Co3 O4 by a margin of 70 mV. Co3– x Pd x O4 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. Abstract : Direct electrolysis of pH‐neutral seawater is not only a promising approach to produce clean hydrogen energy, but also of great significance to seawater desalination. Now, both the simulations and experimental characterizations illustrate that incorporating the strong‐proton‐adsorption cations into Co3 O4 can increase the rate‐determining water dissociation step and achieve industrially required current density of >200 mA cm −2 in natural seawater.