Interface Engineering of a Hierarchical P-Modified Co/Ni₃P Heterostructure for Highly Efficient Water Electrolysis Coupled with Hydrazine Degradation

Abstract

Energy-saving water electrolysis is an ideal strategy to realize the grid-scale generation of hydrogen fuel, especially by coupling with an alternating hydrazine oxidation reaction (HzOR). However, the lack of selfsupporting electrodes with excellent bifunctional performance is the key to the problem of high operating voltages. Herein, a unique alternating electrodeposition strategy is first developed to design a (P−Co/Ni 3 P) A3 /NF (NF = nickel foam) electrode, which has a hierarchical heterostructure for more active sites and robust interface interactions, resulting in excellent bifunctional activity. The (P−Co/Ni 3 P) A3 /NF electrode exhibits small potentials of −10 and −79 mV at 10 mA cm −2 as well as low Tafel slopes of 45 and 1.8 mV dec −1 for the hydrogen evolution reaction (HER) and HzOR, respectively. Inspiringly, an extremely small-cell voltage of 50 mV is required to realize a high current density of 300 mA cm −2 in the twoelectrode device, which is 1.77 V lower than that in the overall water splitting (1.82 V) system. Density functional theory calculations confirm that the construction of the P−Co/Ni 3 P heterostructure achieves the improvement of the calculated adsorption energy of the H 2 O molecule (ΔG Hd 2 O ), ΔG H* , as well as the dehydrogenation kinetics of reaction intermediates, thereby accelerating the overall electrocatalytic activity of HER/HzOR. Our strategy suggests a possibility for the development of other material synthesis and performance optimization for hydrogen production.

Nanostructure engineering of ruthenium-modified electrocatalysts for efficient electrocatalytic water splitting

“…7–10 However, the sluggish reaction kinetics caused by the multiple electron transfer process lead to a large consumption of electrical energy, limiting the energy conversion efficiency of overall water electrolysis. 11–13 Moreover, the harsh corrosive electrolytic condition is a challenge for highly efficient H 2 production. 14–16 Therefore, the application of active electrocatalysts with sufficient stability is ideal to extend the practical application of overall water splitting.…”

Promoting water splitting by transforming its presence status for enhanced hydrogen evolution

“…[7][8][9] The oxygen evolution reaction limits the efficiency of overall water splitting for H 2 generation, but the assistance of a sacrificial reagent can yield higher H 2 generation efficiencies. [10][11][12][13] To avoid the acidic etching of catalysts and equipment or to improve the efficiency of H 2 evolution, a non-acidic medium is often used in H 2 evolution systems. [13][14][15][16][17] In non-acidic solutions, the water dissociation step decreases the velocity of the H 2 evolution reaction (HER).…”

“…7–9 The oxygen evolution reaction limits the efficiency of overall water splitting for H 2 generation, but the assistance of a sacrificial reagent can yield higher H 2 generation efficiencies. 10–13…”

Interface Engineering Modulation Combined with Electronic Structure Modification of Zn-Doped NiO Heterostructure for Efficient Water-Splitting Activity

“…For bifunctional electrocatalytic activities of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), several promising transition-metal-containing electrocatalysts have been reported, such as oxides, hydroxides, , oxyhydroxides, sulfides, phosphides, borides, carbides, nitrides, and selenides . Recently, nickel-based electrocatalysts have been reported to show good HER and OER performances in alkaline media. , However, their limited surface-active species impact mass transfer and overall electrocatalytic performance. , To resolve this issue, several researchers have attempted to improve the catalytic performances by doping the matrix with heteroatoms, , formulating hybrid heterostructures, and growing electroactive matrices on conducting material substrates . Since the HER and OER occur at the catalyst’s surface, it is essential to engineer the catalyst surface for improved catalytic performances.…”

“…20,21 However, their limited surface-active species impact mass transfer and overall electrocatalytic performance. 22,23 To resolve this issue, several researchers have attempted to improve the catalytic performances by doping the matrix with heteroatoms, 24,25 formulating hybrid heterostructures, 26 and growing electroactive matrices on conducting material substrates. 27 Since the HER and OER occur at the catalyst's surface, it is essential to engineer the catalyst surface for improved catalytic performances.…”