Boride-derived oxygen-evolution catalysts

Ning Wang,Xuhui Sun,Mei Han,Sung‐Fu Hung ,Yongchang Liu,Adnan Ozden,Aoni Xu,Ying‐Rui Lu ,Pei‐Hsuan Chen ,Yujian Xia,Edward H Sargent,Alberto Vomiero,Ali Seifitokaldani,David Sinton,Kaili Yao,Ziyun Wang,Fang–Jing Wu ,Jingrui Han,Yu Yan,Jehad Abed,Meng‐Jia Sun ,Pengfei Ou,Hongyan Liang

doi:10.1038/s41467-021-26307-7

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/cm2 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/cm2. We couple the catalyst with CO reduction in an alkaline membrane electrode assembly electrolyser, reporting stable C2H4 electrosynthesis at current density 200 mA/cm2 for over 80 h.

Highlights

Metal borides/borates have been considered promising as oxygen evolution reaction catalysts; to date, there is a dearth of evidence of long-term stability at practical current densities
We carried out density functional theory (DFT) calculations to further explore the effects of these in-situ formed phases on the oxygen evolution reaction (OER) activity of NiFe catalyst
We found that FeBO3 and NiB4O7 were formed under an applied potential (Fig. 3a, the standard patterns are provided in the Supplementary Fig. 10), consistent with in-situ formation of new phases in the NiFe-Boride catalyst during OER

Summary

Introduction

Metal borides/borates have been considered promising as oxygen evolution reaction catalysts; to date, there is a dearth of evidence of long-term stability at practical current densities. The lack of highly active and stable OER catalysts limits the performance and stability of electrosynthesis processes that rely on an OER anode (i.e., CO2RR/CORR electrolysers) to production rates

Methods

Results

Conclusion