Electrocatalysis by crown-type polyoxometalates multi-substituted by transition metal ions; Comparative study

NiCoPd Inlaid NiCo-Bimetallene for Efficient Electrocatalytic Methanol Oxidation

Pd-based metallenes have attracted great attention recently as newly burgeoning two-dimensional (2D) materials, attributed to their significantly increased active surface areas and intrinsic electrocatalytic activities. Therefore, they could be used as a potential candidate as the high-performance electrocatalyst for methanol oxidation reactions (MORs) in the direct methanol fuel cell. Herein, a new strategy is proposed to fabricate NiCoPd inlaid NiCo-bimetallene (NiCoPd/NiCo-bimetallene) by the structure directing effect of 18-crown-6 ether under an ultrasonic-pulse interface together with the HCHO reduction and atom-diffusion-aging process. NiCoPd ternary-alloys with uniformly dispersed Pd active sites are decorated onto NiCo-bimetallenes, achieving remarkably enhancing the effective utilization of Pd atoms. What is more, the intrinsic activity is enhanced by the "bifunctional mechanism" of NiCo-bimetallene adsorption of intermediate species and increased Pd-active sites. Moreover, the anti-CO poisoning ability is optimized through the "alloying ligand effect" of NiCoPd. Therefore, the NiCoPd/NiCo-bimetallene exhibits excellent mass activity for MOR, which is higher than commercial Pd/C. This work suggests a new way of the Pd-based metallenes catalyst approach to the efficient electrocatalytic MOR.

Polyoxometalate-based composite materials in electrochemistry: state-of-the-art progress and future outlook

Polyoxometalates (POMs) have been developed as a class of promising smart material candidates not only due to their multitudinous architectures but also their good redox activities and outstanding electron and proton transport capacities. Recently, abundant studies on POMs composited with metal nanoparticles (NPs), carbon materials (e.g., carbon nanotubes (CNTs), carbon quantum dots (CQDs), graphene), and conducting polymers or highly-porous framework materials (e.g., MOFs, ZIFs) have been performed and POM-based composite materials (PCMs) undoubtedly show enhanced stability and improved electrochemical performances. Therefore, POMs and PCMs are of increasing interest in electrocatalysis, electrochemical detection and energy-related fields (such as fuel cells, redox flow batteries and so on), thus, developing novel PCMs has long been the key research topic in POM chemistry. This review mainly summarizes some representative advances in PCMs with electrochemical applications in the past ten years, expecting to provide some useful guidance for future research.

Vanadium substituted Keggin-type POM-based electrochromic films showing high performance in a Li+-based neutral non-aqueous electrolyte

Vanadium substituted Keggin type POM-based electrochromic films show high performance in LiClO₄-based non-aqueous electrolyte. The use of the neutral non-aqueous electrolyte makes it easy to fabricate a device.