MnOx -Decorated Nickel-Iron Phosphides Nanosheets: Interface Modifications for Robust Overall Water Splitting at Ultra-High Current Densities

Pan Wang; Yuanzhi Luo; Gaixia Zhang; Mingjie Wu; Zhangsen Chen; Shuhui Sun; Zhicong Shi

doi:10.1002/smll.202105803

MnO_x -Decorated Nickel-Iron Phosphides Nanosheets: Interface Modifications for Robust Overall Water Splitting at Ultra-High Current Densities

Small. 2022 Feb;18(7):e2105803. doi: 10.1002/smll.202105803. Epub 2021 Dec 10.

Authors

Pan Wang^{1

2

3}, Yuanzhi Luo¹, Gaixia Zhang³, Mingjie Wu³, Zhangsen Chen³, Shuhui Sun³, Zhicong Shi¹

Affiliations

¹ Institute of Batteries, School of Materials and Energy, Guangdong University of Technology, Guangzhou, 510006, China.
² The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510641, China.
³ Énergie Matériaux Télécommunications Research Centre, Institut National de la Recherche Scientifique (INRS), Varennes, Québec, J3X 1S2, Canada.

PMID: 34894072
DOI: 10.1002/smll.202105803

Abstract

Exploring highly active and stable bifunctional water-splitting electrocatalysts at ultra-high current densities is remarkably desirable. Herein, 3D nickel-iron phosphides nanosheets modified by MnO_x nanoparticles are grown on nickel foam (MnO_x /NiFeP/NF). Resulting from the electronic coupling effect enabled by interface modifications, the intrinsic activities of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are improved. Meanwhile, 3D nanosheets provide abundant active sites for HER and OER, leading to accelerating the reaction kinetics. Besides, the shell-protection characteristic of MnO_x improves the durability of MnO_x /NiFeP/NF. Therefore, MnO_x /NiFeP/NF shows exceptional bifunctional electrocatalytic activities toward HER (an overpotential of 255 mV at 500 mA cm^-2 ), OER (overpotentials of 296 and 346 mV at 500 and 1000 mA cm^-2 , respectively), and overall water splitting (cell voltages of 1.796 and 1.828 V at 500 and 1000 mA cm^-2 , respectively). Furthermore, it owns remarkably outstanding stability for overall water splitting at ultra-high current densities (120 and 70 h at 500 and 1000 mA cm^-2 , respectively), which outperforms almost all of the non-noble metal electrocatalysts. This work presents efficient strategies of interface modifications, 3D nanostructures, and shell protection to afford ultra-high current densities.

Keywords: bifunctional electrocatalysts; manganese oxides; nickel-iron phosphides; ultra-high current densities; water splitting.

Abstract

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