Work-function-induced interfacial electron redistribution of MoO_(2)/WO_(2) heterostructures for high-efficiency electrocatalytic hydrogen evolution reaction

The engineering of the electronic configurations of active sites,together with the production of more accessible active sites through heterostructure design,has been established as a forceful methodology for boosting water electrolysis performance.Herein,a facile approach is developed to fabricate well-dispersed MoO_(2) and WO_(2) nanoparticles with abundant heterointerfaces entrapped in N,P-doped carbon nanofibers(referred to as MoO_(2)/WO_(2)@N,P-CNFs hereafter)as hydrogen evolution reaction(HER)electrocatalysts in alkaline and acidic electrolytes.Extensive spectroscopic analyses and theoretical findings manifest that the heterointerface formed by the work function modulation of MoO_(2)/WO_(2) triggers the spontaneous electron redistribution from MoO_(2)to WO_(2) and a built-in electric field,which is essential to promote water adsorption,optimize the H-intermediate adsorption energy,result in the enhanced charge transfer efficiency,and ultimately increase the intrinsic HER activity.Simultaneously,the intimate confinement of MoO_(2)/WO_(2) heterostructures in the porous carbon substrate can restrain the active sites from unfavorable coarsening and detachment,thus ensuring facilitated HER kinetics and outstanding structural robustness.As a result,MoO_(2)/WO_(2)@N,P-CNFs exhibit superior catalytic HER performance in acidic and basic solutions,requiring 118 and 95 mV overpotentials to achieve 10 mA·cm^(−2),respectively,surpassing a number of reported non-noble metal-based electrocatalysts.This work provides guidelines for the rational design and construction of special metallic heterocomponents with optimized interfacial electronic structure for various electrochemical technologies.

Asymmetric electrode design with built-in nitrogen transfer channel achieving maximized three-phase reaction region for electrochemical ammonia synthesis

Carbon-free electrochemical nitrogen reduction reaction(NRR)is an appealing strategy for green ammonia synthesis,but there is still a significant performance bottleneck.Conventional working electrode is usually flooded by the electrolyte during the NRR test,and only the surface material could get access to the nitrogen,which inevitably gives rise to sluggish reaction rate.Herein,an asymmetric electrode design is proposed to tackle this challenge.An aerophilic layer is constructed on one face of the electrocatalyst-loaded electrode,while the other side maintains its original structure,aiming to achieve facilitated nitrogen transfer and electrolyte permeation within the conductive skeleton simultaneously.This asymmetric architecture affords extensive threephase reaction region within the electrode as demonstrated by the combination of theoretical simulations and experimental measurements,which gives full play to the loaded electrocatalyst.As expected,the proofof-concept asymmetric electrode delivers an NH_(3)yield rate of 40.81μg h^(−1)mg^(−1)and a Faradaic efficiency of 71.71%at−0.3 V versus the reversible hydrogen electrode,which are more than 4 and 7 times that of conventional electrode,respectively.This work presents a versatile strategy for enhancing the interfacial reaction kinetics and is instructive to electrode design for gas-involved electrochemical reactions.