Quasi-Two-Dimensional Earth-Abundant Bimetallic Electrocatalysts for Oxygen Evolution Reactions

Abstract

The extremely large surface area offered by quasi-twodimensional (2D) nanostructures is a great advantage for catalytic applications. While bimetallic materials have been discovered as a group of promising catalysts for electrochemical water splitting, a facile and reliable synthesis approach toward 2D morphology to fully release its electrochemical catalytic potential is still lacking. In this work, bimetallic Co−Mo−O ultrathin nanosheets were synthesized by ionic layer epitaxy with controlled composition ratio. The Co−Mo−O nanosheets exhibited a quadrangle shape with a uniform thickness of ∼2.5 nm. This 2D morphology largely enriched the surface catalytic active site ratio. Particularly, nanosheets with 2:1 Co-to-Mo ratio showed a substantially enhanced OER catalytic activity with a 3 orders of magnitude higher mass activity compared to benchmark IrO 2 and RuO 2 in an alkaline environment. This study introduces a promising possibility for creating high-performance electrocatalysts from 2D bimetallic materials with a high efficiency for material utilization.

Water-Splitting Artificial Leaf Based on a Triple-Junction Silicon Solar Cell: One-Step Fabrication through Photoinduced Deposition of Catalysts and Electrochemical Operando Monitoring

“…24,37 In the Co 2p spectrum, the main and satellite Co2p 3/2 was observed at 781.3 and 785.9 eV, respectively, that suggested the presence of the Co 2+ oxidation state. 25,38 P 2p3/2 was found at 132.9 eV, being consistent with a phosphate species adsorbed onto the cobalt oxide surface. 24,34,39,40 Sulfur was not found.…”

“…In the W4f core spectrum, a doublet with a W4f 7/2 binding energy of 35.36 eV was found, indicating the presence of the W 6+ oxidation state (Figure S13). , In the Co 2p spectrum, the main and satellite Co2p 3/2 was observed at 781.3 and 785.9 eV, respectively, that suggested the presence of the Co 2+ oxidation state. , P 2p3/2 was found at 132.9 eV, being consistent with a phosphate species adsorbed onto the cobalt oxide surface. ,,, Sulfur was not found. Thus, all analyses performed on CoWO deposited onto ITO show full similarity with the same material deposited on FTO and indicate that CoWO is an amorphous cobalt tungsten oxide having surface-bound phosphate species.…”

“…Over years of intensive development, several promising H 2 -evolving and O 2 -evolving catalysts made of earth-abundant elements are available. Among these, bimetallic sulfides such as cobalt molybdenum sulfide − or cobalt tungsten sulfide , are promising noble metal-free H 2 -evolving catalysts, whereas their oxide/hydroxide counterparts are active O 2 -evolving catalysts. − Few of these bimetal sulfides or oxides were reported to be efficient bifunctional or Janus catalysts for driving the overall water splitting. , These materials can be prepared as thin films on a conducting or semiconducting electrode via electrochemical or photoassisted electrochemical deposition. For example, some of us reported that using a solution of [Co­(WS 4 ) 2 ] 2– in a pH 7 phosphate buffer, a cobalt tungsten sulfide layer (denoted hereafter as CoWS) active for H 2 evolution can be grown at an onset cathodic potential of ∼+0.1 V vs RHE (hereafter, we arbitrarily define onset (over)­potentials as the (over)­potential values at which the modulus of the current density exceeds 0.1 mA·cm –2 ) .…”

Accelerating the reaction kinetics of lithium–oxygen chemistry by modulating electron acceptance–donation interaction in electrocatalysts

“…S1a †). 31 Impressively, associated with the continuous introduction of Co nodes, the advantageous nanosheet morphology can be well retained (Fig. 1d and S1b †).…”

Reactive template-engaged synthesis of Ni-doped Co3S4 hollow and porous nanospheres with optimal electronic modulation toward high-efficiency electrochemical oxygen evolution

“…[1][2][3][4][5] The oxygen evol-ution reaction (OER), as an indispensable reaction involved in the above energy-related systems, usually suffers from the sluggish kinetics due to the complicated 4e − transfer process and high energy barrier for the formation of the O-O bond. [6][7][8][9] Accordingly, high-efficiency electrocatalysts are essential to reduce the reaction overpotential and promote the reaction rate. [10][11][12] Until now, noble-metal RuO 2 -/IrO 2 -based materials are generally regarded as benchmarks for the OER, while their widespread application is restricted by their high price and scarce abundance.…”