Constructing MoP_x@MnP_y Heteronanoparticle-Supported Mesoporous N,P-Codoped Graphene for Boosting Oxygen Reduction and Oxygen Evolution Reaction

Abstract

Developing efficient and cost-effective bifunctional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly important for fabricating energy conversion and storage technologies, such as fuel cells, water electrolyzers, and metal–air batteries. Herein, we report a facile and economical route for synthesizing ultrasmall molybdenum phosphide (MoP y ) nanocrystal-attached mesoporous manganese phosphides on N,P-codoped graphene nanosheets, which display equivalent ORR (OER) activity to that of Pt/C (RuO2) catalysts. This is manifested by the positive onset potential (0.969 V) and half-wave potential (0.842 V) for ORR, as well as a mere overpotential of 301 mV at a current density of 20 mA·cm–2 and a small Tafel slope of 105 mV·dec–1 for OER in alkaline medium. It also demonstrates remarkable stability in comparison with Pt/C and RuO2 for both ORR and OER, respectively. The excellent performance can be attributed to the mesoporous structure with enhanced multiple types of electroactive sites, which highly favors the adsorption and catalyzation of reactants, as well as efficient reagent/product mass transport. The findings can pave a new way for the synthesis and usage of a hybrid as a bifunctional catalyst with high efficiency and outstanding longevity to enable next generation of energy conversion and storage.

Single Atoms and Clusters Based Nanomaterials for Hydrogen Evolution, Oxygen Evolution Reactions, and Full Water Splitting

“…Recently, molybdenum phosphide (MoP) hybridized with other transition metal phosphide (MP) which have high thermal stability and electronic conductivity has been reported as an active OER catalyst . The lone pair electron of P atoms in metal phosphides is modulating the surface charge which facilitates the reactant adsorption on the catalyst for efficient OER catalyzing reactions 194b. Moreover, the bimetallic phosphide also synergistically enhanced electrochemical properties that can significantly modify the reactants adsorption energy .…”

“…The lone pair electron of P atoms in metal phosphides is modulating the surface charge which facilitates the reactant adsorption on the catalyst for efficient OER catalyzing reactions 194b. Moreover, the bimetallic phosphide also synergistically enhanced electrochemical properties that can significantly modify the reactants adsorption energy . For example, Lee and coworkers reported the hybrid of MnP x and MoP y on N/P codoped graphene NSs (MnP x @MoP y /N, P‐Gr) as an OER electrocatalyst 194a.…”

“…Moreover, the bimetallic phosphide also synergistically enhanced electrochemical properties that can significantly modify the reactants adsorption energy . For example, Lee and coworkers reported the hybrid of MnP x and MoP y on N/P codoped graphene NSs (MnP x @MoP y /N, P‐Gr) as an OER electrocatalyst 194a. The as‐synthesized MnP x @MoP y /N, P‐Gr hybrid displayed η 20 = 301 mV with ζ = 105 mV dec −1 and durability for 30 h in 1 m KOH solution.…”

“…The electrocatalytic activity of the catalyst strongly depends on its structural features and electrochemical surface active areas as well as the intrinsic catalytic nature of the metal 194b,196. The designing of MoP hybridized with intrinsically active OER NiP in 2D or 3D NSs that have rich oxygen vacancies can greatly improve the electrical conductivity and reduces energy for OH − adsorption on the electrode surface.…”

“…The designing of MoP hybridized with intrinsically active OER NiP in 2D or 3D NSs that have rich oxygen vacancies can greatly improve the electrical conductivity and reduces energy for OH − adsorption on the electrode surface. In this instance, the 3D hollow nanoflower of MoNiP (denoted as Mo 1 Ni 1 P HNFs) that have the structural properties of both 2D and 3D nanostructure were synthesized through a hydrothermal process using NiCl 2 ·6H 2 O, Na 2 MoO 4 ·2H 2 O and NaH 2 PO 2 as Ni, Mo, and P precursors, respectively 194b. The Mo 1 Ni 1 P HNFs exhibited η 10 = 275 mV with ζ = 56.3 mV dec −1 and durability for 36 h in 1 m KOH solution.…”