Boosting Alkaline Hydrogen and Oxygen Evolution Kinetic Process of Tungsten Disulfide‐Based Heterostructures by Multi‐Site Engineering

Abstract

alkaline electrolyzers are still inefficient due to the existence of large overpotentials induced from the sluggish kinetics of hydrogen and oxygen evolution reactions (HER and OER), thus leading to high electric power consumption and high costs for hydrogen production. [1][2][3] Therefore, it is of great importance to develop advanced HER and OER electrocatalysts to accelerate the kinetics and greatly reduce the overpotentials for water splitting. However, the current state-of-the-art electrocatalysts for water splitting are mainly based on noble metals or noble metal-related materials (e.g., Pt, Pd, IrO 2 , and RuO 2 ), which greatly restrict the large-scale application of industrial water electrolysis due to the high price and low reserves of these materials. In this regard, developing low-cost and earthabundant electrocatalysts with high activity and good stability is crucial for increasing the energy conversion efficiency of water splitting. [4][5][6] In addition, considering the system simplification and cost-cutting in practical commercialization, constructing an advanced bifunctional electrocatalyst with outstanding OER and HER activities in the same media is technologically imperative. [7][8][9] Although some progress has been made during the past few years, it still remains challenging to develop bifunctional non-noble metal-based catalysts with exceptional performance for overall water splitting.To date, a variety of non-noble and earth-abundant materials have been reported as potential catalysts for HER or OER Alkaline water electrolysis is an advanced technology for scalable H 2 production using surplus electricity from intermittent energy sources, but it remains challenging for non-noble electrocatalysts to split water into hydrogen and oxygen efficiently, especially for tungsten disulfide (WS 2 )-based catalysts. Density functional theory calculations in combination with experimental study are used to establish a multi-site engineering strategy for developing robust WS 2 -based hybrid electrocatalyst on mesoporous bimetallic nitride (Ni 3 FeN) nanoarrays for bifunctional water splitting. This ingenious design endows the catalyst with numerous edge sites chemically bonded with the conductive scaffold, which are favorable for water dissociation and hydrogen adsorption. Benefiting from the synergistic advantages, the N-WS 2 /Ni 3 FeN hybrid exhibits exceptional bifunctional properties for hydrogen and oxygen evolution reactions (HER and OER) in base with excellent large-current durability, requiring 84 mV to afford 10 mA cm −2 for HER, and 240 mV at 100 mA cm −2 for OER, respectively. Assembling the catalytic materials as both the anode and cathode to construct an electrolyzer, it is actualized very good activities for overall water splitting with only 1.5 V to deliver 10 mA cm −2 , outperforming the IrO 2 (+) //Pt (−) coupled electrodes and many non-noble bifunctional electrocatalysts thus far. This work provides a promising avenue for designing WS 2 -based heterogeneous electrocatalysts for water el...

Cerium-Doped Nickel Phosphide Nanosheet Arrays as Highly Efficient Electrocatalysts for the Hydrogen Evolution Reaction in Acidic and Alkaline Conditions

“…The increased ECSA for Ce 0.03 -Ni 2 P@NF, Ce 0.06 -Ni 2 P@NF, and Ce 0.10 -Ni 2 P@NF suggest more accessible active sites with the introduction of Ce heteroatoms. ,, The intrinsic electrocatalytic activity can be assessed by the ECSA-normalized polarization curve, which can exclude the effect of differences in the ECSA on the overall electrode activity. ,,, As shown in Figure S7f, the current density was normalized by the ECSA value . Compared with pure Ni 2 P, Ce 0.03 -Ni 2 P@NF, Ce 0.06 -Ni 2 P@NF, and Ce 0.10 -Ni 2 P@NF exhibited greater ECSA-normalized current density at the same potential, implying enhanced intrinsic activity for the HER due to cerium doping. ,, Moreover, we also quantified the TOF values at different potentials to further investigate the intrinsic catalytic activities for the HER. The number of active sites can be determined by a normal electrochemical method (Figure S8a).…”

“…45 Compared with pure Ni 2 P, Ce 0.03 -Ni 2 P@NF, Ce 0.06 -Ni 2 P@NF, and Ce 0.10 -Ni 2 P@NF exhibited greater ECSA-normalized current density at the same potential, implying enhanced intrinsic activity for the HER due to cerium doping. 18,49,77 Moreover, we also quantified the TOF values at different potentials to further investigate the intrinsic catalytic activities for the HER. The number of active sites can be determined by a normal electrochemical method (Figure S8a).…”

SnTe nanomaterial decorated over graphene nanosheet for robust OER activity

“…Among all, the electrochemical splitting of water into H 2 and O 2 is often regarded as a vital stage in extraordinary nonconventional energy production, energy storage, and distribution. 13,14 The two processes in the electrolysis of water are the hydrogen evolution reaction (HER) as the result of reduction at the cathode and the oxygen evolution reaction (OER) due to oxidation at the anode. [15][16][17][18][19] A potential difference of 1.23 V between anode and cathode is required to drive the complete water splitting reaction.…”

Advances in Interfacial Engineering and Their Role in Heterostructure Formation for HER Applications in Wider pH

“…In this work, Mo acted as an electronic modulator that concurrently modified Ni and Co, by activating Ni and balancing the overbinding effect of Co. 58 Apart from CoS 2 , MoS 2 also formed a heterostructure with its analogue WS 2 to generate a maximum number of active sites at the interface for HER in acidic medium as suggested by Vikraman et al 59 WS 2 , as less explored as an HER material, formed interfaces with various metal sulfides such as CoS 2 and displayed excellent HER performance as a core−shell structure in KOH. 60 Very recently, Yu et al 61 fabricated mesoporous nickel iron nitride nanoarrays as a conductive scaffold of WS 2 as a robust hybrid electrocatalyst. This hybrid catalyst encouraged optimal hydrogen adsorption free energy and low kinetic barrier for water dissociation at the interface in alkaline media.…”