Nanoframes of Co₃O₄–Mo₂N Heterointerfaces Enable High‐Performance Bifunctionality toward Both Electrocatalytic HER and OER

Abstract

Interfacial engineering of heterostructured catalysts has attracted great interest in enabling both hydrogen and oxygen evolution reactions (HER and OER), by fine tuning of the interfacial geometry and electronic structures. However, they are not well structured for high-performing bifunctionalities, largely due to the confined single particle morphologies, where the exposed surfaces and interfaces are limited. Herein, a hollow nanoframing strategy is purposely devised for interconnected Co 3 O 4 -Mo 2 N heterostructures that are designed with interfacial charge transfer from Mo 2 N to Co 3 O 4 , as rationalized by theoretical calculations and confirmed by X-ray photoelectron spectroscopy analyses. It is shown that by the controllable pyrolysis of bimetallic Mo-Co Prussian blue analogue nanoframes (NFs) with an optimal Mo/Co ratio, the desired nanoframes of Co 3 O 4 -Mo 2 N heterostructure are successfully formed. The as-synthesized Co 3 O 4 -Mo 2 N NFs not only inherit the functionalities of individual components and the electrolyte-accessible nanoframe structure, and they also give an ideal heterointerface with strong electron interaction and favorable H 2 O/H* adsorption energies, leading to a remarkable enhancement in bifunctional catalytic activities (i.e., 12.9-fold and 20-fold higher current density under the 300 mV overpotential, as compared to the single-phased Co 3 O 4 NFs alone toward HER and OER, respectively), while remaining a robust stability.

Disordered spinel cobalt oxide electrocatalyst for highly enhanced HER activity in an alkaline medium

“…[17][18][19][20][21][22][23] Among them, Co 3 O 4 spinel oxide is considered as a potential material for developing efficient electrocatalysts due to its outstanding redox activity facilitated by Co 2+ and Co 3+ ions and good stability in an alkaline medium. [24][25][26][27] An excellent OER active Co 3 O 4 electrocatalyst has been reported by controlling the morphologies, defects and oxygen vacancies. [28][29][30][31][32][33][34][35][36][37] Oxygen vacancy engineering and stabilizing oxygen vacancies played significant roles for enhancing the OER activity.…”

Design and Synthesis of Hollow Nanostructures for Electrochemical Water Splitting

“…As a typical example, Mu and co‐workers developed a unit‐exchange strategy between [MoO 4 ] in (NH 4 ) 6 Mo 7 O 24 and [Co‐N x C y ] units in Co PBA. [ 69 ] After subsequent pyrolysis, the resultant Co 3 O 4 ‐Mo 2 N nanoframes inherit the functionalities of individual components and demonstrate outstanding activities toward both HER and OER.…”

Improved hydrogen evolution performance by engineering bimetallic AuPd loaded on amino and nitrogen functionalized mesoporous hollow carbon spheres

“…Fourthly, the more electron depletion state of Pd in Au 0.3 Pd 0.7 /NH 2 -N-HMCS caused by metal-support interactions and electron synergetic effect can accelerate the C-H cleavage in the adsorbed formate and the formation of H À . [43][44][45]…”