NiSe Nanowire Film Supported on Nickel Foam: An Efficient and Stable 3D Bifunctional Electrode for Full Water Splitting

Abstract

Active and stable electrocatalysts made from earthabundant elements are key to water splitting for hydrogen production through electrolysis.The growth of NiSe nanowire film on nickel foam (NiSe/NF) in situ by hydrothermal treatment of NF using NaHSe as Se source is presented. When used as a3 Do xygen evolution electrode,t he NiSe/NF exhibits high activity with an overpotential of 270 mV required to achieve 20 mA cm À2 and strong durability in 1.0 m KOH, and the NiOOH species formed at the NiSe surface serves as the actual catalytic site.T he system is also highly efficient for catalyzing the hydrogen evolution reaction in basic media. This bifunctional electrode enables ah igh-performance alkaline water electrolyzer with 10 mA cm À2 at ac ell voltage of 1.63 V.Hydrogen has been considered as ac lean energy resource to replace the diminishing fossil fuel. [1,2] Electrochemical water splitting is awell-established commercial technology to convert electricity produced from intermittent renewable energy resources (such as solar energy,w ind, wave power) into chemical energy stored by hydrogen fuel, addressing the issues of effective storage and transport.[3] Although offering an effective way to make high-purity hydrogen, its practical use for mass hydrogen production is limited because it is as trongly uphill reaction with large overpotential (commercial electrolyzers typically operating at ac ell voltage of 1.8-2.0 V, which is much higher than the theoretical minimum value of 1.23 V).[4] Active electrocatalysts for anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER) are implemented to overcome the large water-splitting overpotentials,m aking the process more energy-efficient.[5] Currently,I r-and Ru-based compounds have the highest activity toward the OER, [6] and platinum group metals are the most efficient HER catalysts, [7] but they suffer from scarcity and high cost, limiting their widespread use.I ti st hus attractive to design efficient OER and HER catalysts made from earth-abundant elements and, indeed, great progress has been achieved during the past years in developing non-precious metal catalysts with high activity for OER (cobalt phosphate, [8] oxides, [9][10][11][12] hydroxides [13][14][15][16][17] )a nd HER (chalcogenides, [18][19][20][21] carbides, [22,23] phosphides [7,[24][25][26][27] ). Water splitting must be performed in either strongly acidic or alkaline solution to minimize the overpotentials, [28] which however is challenging for earth-abundant catalysts because ahigh-efficiencycatalyst at acidic pH may be inactive or even unstable at alkaline pH and vice versa. Using ab ifunctional OER and HER catalyst has advantages of simplifying the system and lowering the cost. Because acidic water splitting suffers from the use of scarce and expensive acid-insoluble OER catalysts with reasonable activity, [29] alkaline water splitting has emerged as as trong candidate for commercialization toward mass hydrogen production.[4] It is thus highly attractive to make...

Cobalt-vanadium bimetal-based nanoplates for efficient overall water splitting

“…The materials based on early and late transition metals (ETMs and LTMs) are promising for HER and OER [14,15], such as the transition metals sulfides [16,17], phosphides [18][19][20][21][22], selenide [23], nitride [24][25][26] and carbides [27] for HER, and oxides (Ni oxides [28,29] and Co oxides [30][31][32]) for OER. The cobalt (Co), as a typical LTM, is promising in HER due to its relatively low cost and the activity for the reduction of H + [33].…”

Transition metal ions regulated oxygen evolution reaction performance of Ni-based hydroxides hierarchical nanoarrays

“…Previous studies have shown that the OER activity of an ultra-thin γ-CoOOH nanosheet is 20-times higher than that of bulk CoOOH and 2.4-times higher than that of an IrO 2 electrocatalyst26. Well-aligned nanowire arrays have been used as highly effective electrodes, because of their intrinsic advantages272829. Moreover, ordinary electrodes have relatively poor stabilities because of contact between the substrate and electrocatalysts during the electrocatalytic of OER, especially at large current densities.…”

Engineering Ternary Pyrite‐Type CoPS Nanosheets with an Ultrathin Porous Structure for Efficient Electrocatalytic Water Splitting

“…As shown in Figure 5a, the polarization curve indicates that CoPS UPNSs catalyst exhibits superior overall water splitting performance with a cell voltage of 1.57 V to achieve the current density of 10 mA cm À 2 . [55] Moreover, long-term electrolysis also proves that the CoPS UPNSs j j CoPS UPNSs cell maintains superior stability over 24 h (Figure 5b). [55] Moreover, long-term electrolysis also proves that the CoPS UPNSs j j CoPS UPNSs cell maintains superior stability over 24 h (Figure 5b).…”