Fabrication of Polyoxometalate Anchored Zinc Cobalt Sulfide Nanowires as a Remarkable Bifunctional Electrocatalyst for Overall Water Splitting

Abstract

The advancement of a naturally rich and effective bifunctional substance for hydrogen and oxygen evolution reaction is crucial to enhance hydrogen fuel production efficiency via the electrolysis process. Herein, facile and scalable hydrothermal synthesis of bifunctional electrocatalyst of polyoxometalate anchored zinc cobalt sulfide nanowire on Ni-foam (NF) for overall water splitting is reported for the first time. The electrochemical analysis of POM@ZnCoS/NF displays significantly low HER and OER overpotentials of 170/337 and 200/300 mV to attain a current density of 10/40 and 20/50 mA cm −2 , respectively, demonstrating the notable performance of POM@ZnCoS/NF toward H 2 and O 2 evolution reaction in alkaline medium. Additionally, the electrolyzer consisting of the POM@ZnCoS/NF anode and cathode shows an appealing potential of 1.56 V to deliver 10 mA cm −2 current density for overall water splitting. The high electrocatalytic activity of the POM@ZnCoS/NF is attributed to modulation of the electronic and chemical properties, increment of the electroactive sites and electrochemically active surface area of the zinc cobalt sulfide nanowires due to the anchorage of polyoxometalate nanoparticles. These results demonstrate the advantage of the polyoxometalate incorporation strategy for the design of cost-effective and highly competent bifunctional catalysts for complete water splitting.

Homogeneous Elongation of N‐Doped CNTs over Nano‐Fibrillated Hollow‐Carbon‐Nanofiber: Mass and Charge Balance in Asymmetric Supercapacitors Is No Longer Problematic

“…The fine lattice fringes displayed in HR‐TEM indicate the crystallinity and graphitic nature of the material. [ 16 ] The distinct crystalline planes with lattice fringes of 0.35 and 0.21 nm correspond to the (002) plane of graphitic carbon and the (111) plane of metallic Co, respectively. The same result with three distinct rings is noticed from the SAED patterns taken at the area containing both Co‐NPs and graphitic carbon (Figure S1, Supporting Information).…”

Polyoxometalate-based metal–organic complexes and their derivatives as electrocatalysts for energy conversion in aqueous systems

“…In this process, the OER always shows sluggish kinetics, resulting in a higher potential, and it reduces the overall water splitting efficiency. 49,50 Therefore, exploitation of effective and steady catalysts for the OER matters. Meanwhile, the overpotential is required to be lower to achieve the purpose of energy saving.…”

Super‐Hybrid Transition Metal Sulfide Nanoarrays of Co3S4 Nanosheet/P‐Doped WS2 Nanosheet/Co9S8 Nanoparticle with Pt‐Like Activities for Robust All‐pH Hydrogen Evolution

“…Second, according to widely accepted criteria, i.e., free energy of hydrogen adsorption (ΔG H* ), the pure TMSs usually presented unfortunate ΔG H* far from the optimal zero of benchmark Pt. [23,24] Third, the promoted density of active site exposure in electrocatalysts can maximize the utilization of scant electrode surface and thus contribute to the miniaturization of the water-splitting devices. [20,25] For example, although MoS 2 and WS 2 with 2D layered structures can expose basal plane and edge sites, the effective HER active sites are still insufficient.…”