In Situ Formed Edge-Rich Ni₃S₂-NiOOH Heterojunctions for Oxygen Evolution Reaction

Abstract

Developing highly active, earth-abundant, and durable electrocatalysts is desired but challenging for oxygen evolution reaction (OER). In this work, we design an electrocatalyst of the edge-rich nickel sulfide arrays on the nickel foam (Ni3S2 NSs-NF) by a facile yet efficient wet-chemical method. Benefiting from the three-dimensional nanostructure with numerous active edges, the prepared Ni3S2 NSs-NF exhibits superior OER performance in alkaline conditions. An in-depth study reveals that the real active sites toward OER are the in-situ formed heterogenous Ni3S2-NiOOH. Density functional theory calculations indicate the density of state of the Ni3S2-NiOOH heterojunction near the Fermi level is enhanced, contributing to higher electronic conductivity. As a result, the Ni3S2 NSs-NF with abundant Ni3S2-NiOOH heterojunctions exhibits an efficient electrochemical activity toward OER in alkaline conditions. The Ni3S2 NSs-NF electrode shows an overpotential of 244 mV at 10 mA cm−2 with a Tafel slope of 75 mV dec−1 and possesses ultrastable performance even at 100 mA cm−2.

Bifunctional Ni Foam Supported TiO2@Ni3S2 core@shell Nanorod Arrays for Boosting Electrocatalytic Biomass Upgrading and H2 Production Reactions

“…[56,57] Moreover, due to the in situ gen-erated Ni 3 S 2 /NiOOH heterostructure, the Ni/TiO 2 @Ni 3 S 2 electrode exhibited excellent electrocatalytic stability and exposed numerous active sites for OER and GOR reactions. [58][59][60] The SEM and TEM results showed that the morphology of Ni/TiO 2 @Ni 3 S 2 changed more seriously after the GOR reaction. As displayed in Figure 5E a large number of irregular nanosheet thick layers covered on the electrodes after GOR reaction, and HRTEM (Figure 5F) revealed the presence of NiOOH.…”

Hierarchical CoNiO2 Microflowers Assembled by Mesoporous Nanosheets as Efficient Electrocatalysts for Hydrogen Evolution Reaction

“…Fossil fuels are running out and the planet is getting worse, meaning it is really important to develop high-power and energy density alternative energy devices. There is no doubt that hydrogen (H 2 ) is a renewable and clean energy that can be obtained from the environment [ 1 , 2 , 3 , 4 ]. It is well known that hydrogen is the most abundant element on earth; currently, 90% of H 2 is acquired from fossil fuels, leading to the aggravation of the energy crisis [ 5 ].…”

Electrochemically Oxidized Aligned Carbon Nanotube Arrays Embedding Foam Substrates for Water Splitting

“…Over the past years, vast promising transition-metal-based catalysts were designed based on phase engineering, , defect engineering, , and multimetal engineering , to increase the intrinsic activity and the number of exposed active sites or tune the intrinsic electric properties via atomic/molecular orbital coupling. , Among them, transition-metal phosphides have shown excellent catalytic activity in electrolytic water due to the multiple electron orbitals of phosphorus and the good binding energy to hydrogen (H) in different reaction media . However, most of these materials show reduced electroactive sites and reduced conductivity due to the formation of segregated multiphase clusters during the synthesis process, thus weakening the electrochemical activity .…”