Electronic coupling strategy to boost water oxidation efficiency based on the modelling of Trimetallic Hydroxides Ni1-x-yFexCry(OH)2: from theory to experiment
Developing low-cost yet highly efficient earth-abundant electrocatalysts for oxygen evolution reaction
(OER) is of great significance for industrial scale water splitting for clean hydrogen production, as
well as for rechargeable metal-air batteries. In searching for advanced catalysts, it is equally important
to fundamentally understand working mechanism and be able to rationally design and manipulate
catalytic sites. Starting from density functional theory (DFT) calculations as a guidance, our theoretical
model revealed that chromium substitution in nickel-iron hydroxides (Ni1-xFex(OH)2) not only
accelerated the charge transfer but also regulated the adsorption energy of OER intermediates such to
achieve optimal binding strength. Experimentally, chromium was doped into the laminate of Ni1-
xFex(OH)2, resulting in enhanced catalytic performance for oxygen evolution reaction, which
confirmed the predictions from the theoretical data. The porous and ultra-thin ternary Ni1-xyFexCry(OH)2 electrocatalysts were grown directly on a nickel foam (NF) substrate, with an optimum
composition Ni0.66Fe0.27Cr0.07(OH)2/NF identified, which exhibited a superior OER performance, i.e.,
achieving a significant current density of 10 mA cm-2 at a low overpotential of 231 mV, a small Tafel
slope (31 mV dec-1) and an excellent stability at a highly oxidative potential of 1.68 V vs RHE in
alkaline electrolyte. The comprehensive study involving both theoretical and experimental results in
this work provides an insightful guidance in designing efficient OER catalysts for chemical and
electrical energy conversion and storage.
Funding
National Key Research and Development Project (2016YFF0204402 and 2017YFA0206500)
National Natural Science Foundation of China (51732002)
Program for Changjiang Scholars and Innovative Research Team in the University (IRT1205), US National Science Foundation (1561886)
Newton Advanced Fellowship award (NAF\R1\191294)
History
School
Aeronautical, Automotive, Chemical and Materials Engineering
This paper was accepted for publication in the journal Chemical Engineering Journal and the definitive published version is available at https://doi.org/10.1016/j.cej.2020.126144