Octahedral Coordinated Trivalent Cobalt Enriched Multimetal Oxygen‐Evolution Catalysts. Issue 43 (2nd October 2020)

• Record Type: Journal Article
• Authors: Chen, Junsheng; Li, Hao; Yu, Zixun; Liu, Chang; Yuan, Ziwen; Wang, Chaojun; Zhao, Shenlong; Henkelman, Graeme; Li, Shuzhou; Wei, Li; Chen, Yuan
• Is Part Of: Advanced energy materials. Volume 10:Issue 43(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-02
• Subjects: cobalt oxyhydroxide -- electrodeposition -- oxygen evolution reaction -- tungstate -- water splitting; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202002593
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Octahedral coordinated trivalent cobalt cations (CoOh 3+ ) in metal oxyhydroxides are highly active catalytic sites for the oxygen evolution reaction (OER), a critical bottleneck for efficient water splitting; however, previous synthetic methods have limited control over these sites. Herein, a scalable electrodeposition method coupled with in situ oxidation to produce amorphous Co–Fe–W trimetallic oxyhydroxides enriched with CoOh 3+ is developed. X‐ray absorption, in operando spectroscopic analysis, and computational studies reveal that 72% of the Co atoms are present in CoOh 3+ sites. Fe and W synergistically affect the electronic structure of Co and provide a favorable coordination environment. The Co–Fe–W oxyhydroxide exhibits superior OER catalytic performance with an impressive turnover frequency of 1.96 s −1 at an overpotential of 300 mV, a low Tafel slope of 32 mV dec −1, and small activation energy of 53 kJ mol −1 in alkaline electrolyte. The catalyst directly deposited on Ni foams can serve as a robust OER electrode in two‐electrode water electrolyzers; they deliver a current density of 100 mA cm −2 at a small overpotential of 234 mV in alkaline electrolyte with excellent durability under 100 mA cm −2 over 120 h. These catalysts are excellent for practical water splitting applications. Abstract : A scalable in situ oxidative electrodeposition method produces Co–Fe–W oxyhydroxide catalysts enriched with highly active octahedral coordinated high‐valence Co sites (CoOh 3+ ). In operando tests reveal CoOh 3+ sites are critical to obtaining superior catalytic performance for the oxygen evolution reaction.