V-doped Ni3N/Ni heterostructure with engineered interfaces as a bifunctional hydrogen electrocatalyst in alkaline solution: Simultaneously improving water dissociation and hydrogen adsorption

Abstract

Alkali-water electrolyzers and hydroxide exchange membrane fuel cells are emerging as promising technologies to realize hydrogen economy. Developing cost-effective electrode materials with high activities towards corresponding hydrogen evolution (HER) and oxidation (HOR) reactions plays a crucial role in commercial hydrogen production and utilization. Herein, we fabricated a V-doped Ni 3 N/Ni heterostructure (V-Ni 3 N/Ni) through a controlled nitridation treatment on a V-incorporated nickel hydroxide precursor. The resultant catalyst exhibits comparable catalytic activity and durability to commercial Pt/C in terms of both HER (a low overpotential of 44 mV at the current density of 10 mA•cm −2 ) and HOR (a high current density of 1.54 mA•cm −2 at 0.1 V versus reversible hydrogen electrode) under alkaline conditions. The superior activity of V-Ni 3 N/Ni grown on different substrates further implies its intrinsic performance. Density functional theory (DFT) calculations reveal that the coupled metallic Ni and doped V can promote the water adsorption, accelerate the Volmer step of alkaline HER, as well as optimize the adsorption and desorption of hydrogen intermediate (H * ) to reach a balanced ∆G H* value.

Vanadium-Doping and Interface Engineering for Synergistically Enhanced Electrochemical Overall Water Splitting and Urea Electrolysis

“…The superior activities of the two V-doped electrocatalysts are comparable or even better than those of previously published transition metal-based HER electrocatalysts (Table S2). Recently, there are several reports concerning boosting the HER performance of transition metal nitrides via V-doping, such as V-Co 4 N (37 mV), V-Ni 3 N (83 mV), V-Ni 0.2 Mo 0.8 N (39 mV), and V-Ni 3 N/Ni (44 mV) . Such improvements were mainly attributed to the tailoring of the electronic structure of metal nitrides, which could promote the adsorption of water, expedite H–OH bond cleavage, and regulate the H* adsorption/desorption during the HER process. , …”

“…Recently, there are several reports concerning boosting the HER performance of transition metal nitrides via V-doping, such as V-Co 4 N (37 mV), 65 V-Ni 3 N (83 mV), 66 V-Ni 0.2 Mo 0.8 N (39 mV), 67 and V-Ni 3 N/Ni (44 mV). 9 Such improvements were mainly attributed to the tailoring of the electronic structure of metal nitrides, which could promote the adsorption of water, expedite H−OH bond cleavage, and regulate the H* adsorption/desorption during the HER process. 65,67 The effects of the V-doping amount and nitridation temperature on the activities for HER were also investigated (Figure S9).…”

“…V-NiFe LDH was prepared according to a previous method with minor modification (see the Supplementary Information). 9 The Ni/Fe/V molar ratio of their corresponding precursor added to the mother liquor was set at 10:2:2.…”

“…7,8 In alkaline medium, the HER process involves the production of a H* intermediate from water dissociation (H 2 O + e − + * → H* + OH − , Volmer step) and the desorption of H 2 derived from the generated H* desorption. 9 When the water dissociation rate is fast and adsorption/ desorption energies of H* are moderate, the H* coverage would be high on the catalyst surface. Then, two H* can combine together (H* + H* → H 2 , Tafel step) to form H 2 following the Volmer−Tafel mechanism.…”

3D Co3O4‐RuO2 Hollow Spheres with Abundant Interfaces as Advanced Trifunctional Electrocatalyst for Water‐Splitting and Flexible Zn–Air Battery

“…[ 35 ] Apart from morphology, the created interfaces in the designed nanomaterials also play a significant part in regulating the electrocatalytic properties by tuning the adsorption/desorption and the transportation of the mids, thus accelerating the reaction kinetics. [ 35,50 ] For instance, Xu et al. outlined that the solid interface between NiSe and Fe 2 O 3 in the prepared NF/NiSe@Fe 2 O 3 favored improvement of the electrocatalytic activity of OER, owing to the easy adsoprtion of intermediated and the desorption of produced O 2 during OER.…”