Boride-derived oxygen-evolution catalysts
Ning Wang, Aoni Xu, Pengfei Ou, Sung‐Fu Hung, Adnan Ozden, Ying‐Rui Lu, Jehad Abed, Ziyun Wang, Yushan Yan, Meng‐Jia Sun, Yujian Xia, Mei Han, Jingrui Han, Kaili Yao, Fengyi Wu, Pei‐Hsuan Chen, Alberto Vomiero, Ali Seifitokaldani, Xuhui Sun, David Sinton, Yongchang Liu, Edward H. Sargent, Hongyan Liang
Abstract
Abstract Metal borides/borates have been considered promising as oxygen evolution reaction catalysts; however, to date, there is a dearth of evidence of long-term stability at practical current densities. Here we report a phase composition modulation approach to fabricate effective borides/borates-based catalysts. We find that metal borides in-situ formed metal borates are responsible for their high activity. This knowledge prompts us to synthesize NiFe-Boride, and to use it as a templating precursor to form an active NiFe-Borate catalyst. This boride-derived oxide catalyzes oxygen evolution with an overpotential of 167 mV at 10 mA/cm 2 in 1 M KOH electrolyte and requires a record-low overpotential of 460 mV to maintain water splitting performance for over 400 h at current density of 1 A/cm 2 . We couple the catalyst with CO reduction in an alkaline membrane electrode assembly electrolyser, reporting stable C 2 H 4 electrosynthesis at current density 200 mA/cm 2 for over 80 h.