Highiy Efficient Water Splitting with Polyoxometalate Coated on Deliberately Designed Porous Carbon as a Bifunctional Electrocatalyst

Abstract

Rational design of efficient, sustainable and low-cost hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) bifunctional catalysts within the scope of feasibility is of great significance for realizing rapid output water splitting. Here, we used a simple coprecipitation method to prepare Keggin-type polyoxometalate (POM) nanoscale particles coated with coreshell-type metal-organic framework (MOF) derived Co-NC (Co-NC-POM). Thanks to synergy effect, abundant active sites, unique structure and defects, the as-synthesized Co-NC-POM hybrids exhibit excellent eletrocatalytic performance both for HER and OER. Moreover, it can act as bifunctional electrocatalysts for overall water splitting, exhibiting a low voltage of 1.60 V and an excellently stability up to 24 h at a current density of 10 mA cm À 2 . It shows competitive performance against the same type of advanced bifunctional catalysts currently reported and thus is expected to among the most efficient non-precious metal catalysts to drive the water splitting device.

Palladium nanoparticles confined in uncoordinated amine groups of metal–organic frameworks as efficient hydrogen evolution electrocatalysts

“…The valence electrons of these metals can still penetrate and interact with aminated Zr-MOF, thus playing a synergistic catalytic role. 29,30 Lattice fringes with a spacing of 0.223 nm were observed in the HRTEM image shown in Fig. 2c.…”

A comprehensive review on the electrochemical parameters and recent material development of electrochemical water splitting electrocatalysts

“…[Bi(OH 2 ) 2 ] 3± functionalized Keggin polyoxometalate (POM) compound was fabricated with ZIF-8, a metal–organic framework containing zinc imidazole; H 5 1@ZIF8 exhibited OER activity with 375 mV, the overpotential and Tafel slope is 188 mV dec −1 in 0.1 M KOH with stability studies carried up to 3 h. 197 The overpotential value @ 10 mA cm −2 and Tafel slopes are found to be 726.04 mV and 173.80 mV dec −1 respectively for the anti-Lipscomb (Krebs type) compound incorporated with cobalt; Na 6 [{CoII(H 2 O) 3 } 2 {W VI (OH )2 } 2 {(Bi III W VI 9 O 33 ) 2 }]·8H 2 O suitable for HER activity to support up to 10 hours of chronoamperometry. 198 Core shell-type metal–organic framework (MOF) derived Co-NC (Co-NC-POM) coated Keggin-type polyoxometalate (POM) nanoscale particles were prepared using a simplistic coprecipitation method by Huimin et al 199 where the as-synthesised Co-NC-POM hybrids exhibited excellent electrocatalytic performance for both HER and OER due to their active sites, distinctive structure, and defects as well as synergy effect. Co-NC-POM has lower overpotential and Tafel value of 133 mV at 10 mA cm −2 and 124 mV dec −1 for HER activity while for OER the catalyst also provides low overpotential of 400 mV with Tafel slope of 94 mV dec −1 with excellent stability up to 24 h and low voltage for overall water splitting 1.60 V. Due to their numerous active sites, atomic-level thickness and substantial surface area, the 2D nanosheets of metal–organic frameworks (MOFs) have recently become recognized as a promising material.…”

Unravelling the Bi‐Functional Electrocatalytic Properties of {Mo72Fe30} Polyoxometalate Nanostructures for Overall Water Splitting Using Scanning Electrochemical Microscope and Electrochemical Gating Methods

“…[ 1 , 2 , 3 ] The principle of electrochemical water splitting can be accompanied by two reactions: i) hydrogen evolution reaction (HER) and ii) oxygen evolution reaction (OER), which are both equally important for an adequate water splitting process. [ 4 , 5 ] The HER occurs at the cathode and converts the water into hydrogen gas, whereas oxygen gas is produced at the anode because of the OER. [ 6 , 7 ] HER is generally effective in acidic conditions (than base), whereas OER is effective only in basic conditions.…”