Ultrathin NiCo Bimetallic Molybdate Nanosheets Coated CuO_x Nanotubes: Heterostructure and Bimetallic Synergistic Optimization of the Active Site for Highly Efficient Overall Water Splitting

Abstract

Rational design and construction of bifunctional electrocatalysts with excellent activity and durability is imperative for water splitting. The regulation of the local electronic structure of the active metal sites in polymetallic composites provides a basic idea. Herein, the ultrathin bimetallic molybdate nanosheets are evenly deposited on the CuOx hollow nanotubes on the copper foam substrate to form a hierarchical heterostructure, which can be used as an efficient bifunctional electrocatalyst for overall water splitting. Experimental results prove that the introduction of Ni to form a double metal salt molybdate and CuOx heterostructure design can be optimized by Co cation as best electronic structure of electric catalytic activity center, and can effectively promote the generation of CoOOH active phase at the same time, so that can skillfully optimize the binding strength between the Co site and the oxygen‐containing intermediate, and enhancing catalytic activity. When it is used in the overall water splitting of a double‐electrode alkaline electrolytic cell, the cell voltage of CoNiMoO4‐21/CuOx/CF is 1.532 V at 50 mA cm−2, far exceeding most of the reported conventional bifunctional electrocatalyst. This work has contributed to understanding the central active sites of polymetallic composites and has provided a useful value for the design of efficient electrocatalysts.

Harnessing the Defects at Hetero‐Interface of Transition Metal Compounds for Advanced Charge Storage: A Review

“…[120] Moreover, heterostructured TMCs with edge/helical dislocations enable the formation of a strain field around the dislocation area, giving rise to charge accumulation. [121] Because the lattice constants of the two materials are often different, this lattice mismatch usually causes a 2D lattice strain near the heterojunction. According to the degree of mismatch between the lattice constants, the interface can be categorized as a coherent interface, semi-coherent interface, or incoherent interface.…”

“…[ 120 ] Moreover, heterostructured TMCs with edge/helical dislocations enable the formation of a strain field around the dislocation area, giving rise to charge accumulation. [ 121 ]…”

Bifunctional catalysts of Ni nanoparticle coupled MoO2nanorods for overall water splitting

“…Thus, it is apparent that Ni NPs play an important role in OER catalytic progress, not only because Ni and the in situ formed oxidized species can act as active sites for the OER but also because the adsorption capacity of the reaction intermediate was optimized on the heterostructure interfaces. 49,50 Besides, the OH − occupancy at the interfaces could reduce the binding of the O intermediate and facilitate the desorption of O 2 molecules. 51 The LSV curves of CNMO-700 with and without iR compensation for the OER are shown in Fig.…”

Interfacial Engineering of Two‐Dimensional MoN/MoO2 Heterostructure Nanosheets as a Bifunctional Electrocatalyst for Overall Water Splitting

“…[7] In recent years, a variety of HER and OER bifunctional nonprecious transition metal electrocatalysts have been reported. [8][9][10] Transition metal compounds have attained immense importance as an electrocatalyst for metal air batteries, supercapacitors, sensors, and water splitting due to their multi valence states, unique electronic stricture, and physical properties. [11] Various non-noble metal compounds have been proposed such as metal oxides, sulfides, carbides, phosphides and nitrides.…”