Bimetallic Nickel‐Substituted Cobalt‐Borate Nanowire Array: An Earth‐Abundant Water Oxidation Electrocatalyst with Superior Activity and Durability at Near Neutral pH |
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| Authors: | Min Ma Fengli Qu Xuqiang Ji Danni Liu Shuai Hao Gu Du Abdullah M. Asiri Yadong Yao Liang Chen Xuping Sun |
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| Affiliation: | 1. College of Chemistry, Sichuan University, Chengdu, Sichuan, China;2. College of Materials Science and Engineering, Sichuan University, Chengdu, Sichuan, China;3. College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong, China;4. Chengdu Institute of Geology and Mineral Resources, Chengdu, Sichuan, China;5. Chemistry Department, King Abdulaziz University, Jeddah, Saudi Arabia;6. Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China |
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| Abstract: | There is an urgent demand to develop earth‐abundant electrocatalysts for efficient and durable water oxidation under mild conditions. A nickel‐substituted cobalt‐borate nanowire array is developed on carbon cloth (Ni‐Co‐Bi/CC) via oxidative polarization of NiCo2S4 nanoarray in potassium borate (K‐Bi). As a bimetallic electrocatalyst for water oxidation, such Ni‐Co‐Bi/CC is superior in catalytic activity and durability in 0.1 m K‐Bi (pH: 9.2), with a turnover frequency of 0.33 mol O2 s?1 at the overpotential of 500 mV and nearly 100% Faradaic efficiency. To drive a geometrical catalytic current density of 10 mA cm?2, it only needs overpotential of 388 mV, 34 mV less than that for Co‐Bi/CC, outperforming reported non‐noble‐metal catalysts operating under benign conditions. Notably, its activity is maintained over 80 000 s. Density functional theory calculations suggest that the O* to OOH* conversion is the rate‐determining step and Ni substitution decreases the free energy on Co‐Bi from 2.092 to 1.986 eV. |
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| Keywords: | Ni‐Co‐Bi nanowire arrays oxidative polarization water oxidation catalysts |
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