Vanadium Substitution Steering Reaction Kinetics Acceleration for Ni₃N Nanosheets Endows Exceptionally Energy-Saving Hydrogen Evolution Coupled with Hydrazine Oxidation

Abstract

Designing highly active transition-metal-based electrocatalysts for energysaving electrochemical hydrogen evolution coupled with hydrazine oxidation possesses more economic prospects. However, the lack of bifunctional electrocatalysts and the absence of intrinsic structure−property relationship research consisting of adsorption configurations and dehydrogenation behavior of N 2 H 4 molecules still hinder the development. Now, a V-doped Ni 3 N nanosheet self-supported on Ni foam (V-Ni 3 N NS) is reported, which presents excellent bifunctional electrocatalytic performance toward both hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER). The resultant V-Ni 3 N NS achieves an ultralow working potential of 2 mV and a small overpotential of 70 mV at 10 mA cm −2 in alkaline solution for HzOR and HER, respectively. Density functional theory calculations reveal that the vanadium substitution could effectively modulate the electronic structure of Ni 3 N, therefore facilitating the adsorption/desorption behavior of H* for HER, as well as boosting the dehydrogenation kinetics for HzOR.

Phase‐Selective Synthesis of Ruthenium Phosphide in Hybrid Structure Enables Efficient Hybrid Water Electrolysis Under pH‐Universal Conditions

“…For N 2 H 4 adsorbed onto the different surfaces, the amount of electron transferred from N 2 H 4 to the RuP surface is 0.04|e| more than that on the Ru 2 P surface, suggesting a stronger interaction between *N 2 H 4 and RuP surface, thus accelerating the subsequent dehydrogenation reaction process. [ 19b,23 ] As for the desorption of N 2 molecule, more charges transfer from the Ru 2 P surface layer to the N 2 ‐intermediate, resulting in the relative instability of *N 2 , which is consistent with the free energy calculation result of the final step. Therefore, the theory and experiment elucidate that the RuP nanocatalysts show superior intrinsic electrocatalytic activity for both HER and HzOR, which would simultaneously realize the optimized hydrogen adsorption and dehydrogenation process.…”

Cerium-induced lattice disordering in Co-based nanocatalysts promoting the hydrazine electro-oxidation behavior

“…14,15 To improve the intrinsic activity of the individual active sites, conducting rational modulation on the electronic structures by means of elemental doping and material hybridization is widely used and highly effective. [16][17][18] For instance, the Zhang group demonstrated that W/P co-doping in Co 3 N could effectively reduce the potential determining step like the dehydrogenation of NHNH* to NHN*, thereby leading to more facile reaction kinetics for HzOR. 19 In addition, the NiCo/MoNi 4 interfaces on amorphous MoO x could also facilitate the HzOR process, leading to highly efficient and durable performance on hydrazine-assisted hydrogen production.…”

Earth‐Abundant Metal‐Based Electrocatalysts Promoted Anodic Reaction in Hybrid Water Electrolysis for Efficient Hydrogen Production: Recent Progress and Perspectives

“…Experiments together with DFT calculations reveal that proper dopants can optimize the electronic structure of host materials and thereby facilitating H* adsorption/desorption during the HER and dehydrogenation kinetics during the HzOR, which is desirable in hydrazine-assisted HWE. [189,190] Moreover, interfacial engineering is a powerful strategy as well to modify adsorption of intermediates and boost electron/mass transportation during the HzOR. [191,192] Therefore, Mai and co-authors fabricated a porous electrode consisting of copper-nickel nitride (Cu 1 Ni 2 -N) nanosheets with rich interfaces supported on carbon fiber cloth via a thermal ammonolysis process of CuNi-LDH.…”