Edge‐oriented N‐Doped WS₂ Nanoparticles on Porous Co₃N Nanosheets for Efficient Alkaline Hydrogen Evolution and Nitrogenous Nucleophile Electrooxidation

Abstract

Abstract Earth‐abundant layered tungsten disulfide (WS 2 ) is a well‐known electrocatalyst for acidic hydrogen evolution, but it becomes rather sluggish for alkaline hydrogen or oxygen evolution due to the low‐density edge sites, poor conductivity, and unfavorable water dissociation behavior. Here, an interfacial engineering strategy to construct an efficient bifunctional electrocatalyst by in situ growing N‐doped WS 2 nanoparticles on highly conductive cobalt nitride (N‐WS 2 /Co 3 N) for concurrent hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) is demonstrated. Benefiting from the good conductivity of Co 3 N, rich well‐oriented edge sites and water‐dissociation sites at the nanoscale interfaces between N‐WS 2 and Co 3 N, the resultant N‐WS 2 /Co 3 N exhibits remarkable HER activity in 1 m potasium hydroxide (KOH) requiring a small overpotential of 67 mV at 10 mA cm −2 with outstanding long‐term durability at 500 mA cm −2 , representing the best alkaline hydrogen‐evolving activity among reported WS 2 catalysts. In particular, this hybrid catalyst also shows exceptional catalytic activities toward theurea oxidation reaction featured by very low potentials of 1.378 and 1.41 V to deliver 100 and 500 mA cm −2 along with superb large‐current stability in 1 m KOH + 0.5 m urea. Moreover, the assembled two‐electrode cell delivers the industrially practical current density of 500 mA cm −2 at a low cell voltage of 1.72 V with excellent durability in alkaline urea‐containing solutions, outperforming most MoS 2 ‐like bifunctional electrocatalysts for overall water splitting reported hitherto. This work provides a promising avenue for the development of high‐performance WS 2 ‐based electrocatalysts for alkaline water splitting.

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