Engineering Surface Structure of Spinel Oxides via High-Valent Vanadium Doping for Remarkably Enhanced Electrocatalytic Oxygen Evolution Reaction

• DOI: 10.1021/acsami.9b10868
• Publication Date: 2019-08-15T10:13:32Z
• Authors: Renjie Wei; Xiuming Bu; Wei Gao; Rovi Angelo B. Vi...; Gennevieve Macam; Zhi-Quan Huang; Changyong Lan; Feng-Chuan Chuang; Yongquan Qu; Johnny C. Ho
• Keywords: Overpotential; Oxygen evolution

Spinel oxides (AB2O4) with unique crystal structures have been widely explored as promising alternative catalysts for efficient oxygen evolution reactions; however, developing novel methods to fabricate robust, cost-effective, and high-performance spinel oxide based electrocatalysts is still a great challenge. Here, utilizing complementary experimental theoretical approach, pentavalent vanadium doping in the (i.e., Co3O4 NiFe2O4) has thoroughly investigated engineer their surface enhanced electrocatalytic reaction. Specifically, when optimal concentration of (ca. 7.7 at. %) incorporated into Co3O4, required overpotential reach certain jGEOM jECSA decreases dramatically reactions alkaline media. Even after 30 h chronopotentiometry, potential V-doped just increases by 16.3 mV, being much lower than that undoped one. It observed introduces lattice distortions defects on surface, which turn exposes more active sites reactions. DFT calculations further reveal rate-determining step changing from *-O *-OOH *-OH *-O, while corresponding energy barriers decrease 1.73 1.57 eV accordingly high-valent V doping. Moreover, intermediate probing method using methanol reagent also demonstrates stronger OH* adsorption When performed inverse matrix NiFe2O4, impressive performance enhancement reaction well witnessed. All these results clearly illustrate process can not only efficiently improve electrochemical properties transition metal but provide new insights design water oxidation electrocatalysts.