High Edge Selectivity of In Situ Electrochemical Pt Deposition on Edge-Rich Layered WS2 Nanosheets

Abstract

Recent studies show that the Pt electrode can be slowly dissolved into the acidic media and regenerate on the working electrode along with the long-time hydrogen evolution reaction (HER) test. However, to date, the relationship between the Pt deposition and the intrinsic properties of the working electrode remains elusive. Herein, for the first time, the edge selectivity of in situ electrochemical Pt deposition on layered 2H-WS₂ nanosheets, whose edge surface with rich dangling bonds is chemically active to regulate their properties, especially the interfacial reaction occurring between the electrode surface and the adjacent thin layer of the solution, is theoretically elucidated and experimentally verified by controlling the cathode polarization test using Pt wire as the counter electrode in H₂SO₄ solution. It is revealed that the layered WS₂ nanosheets with rich exposed edges show much stronger interaction with Pt atoms because the terminated S₂²⁻ or S²⁻ ligands on the edge exhibit much lower binding energy for Pt atoms compared with the apical S²⁻ ligands on the terrace surface. The in situ electrochemical Pt-deposited WS₂ nanosheets with rich exposed edges can act as a highly active hybrid electrocatalyst to accelerate HER kinetics and exhibit commercial Pt-like HER performance, especially in the alkaline media.

Layered WS₂ nanosheets with rich exposed edges show much stronger interaction with Pt atom because the terminated S₂²⁻ or S²⁻ ligands on the edge exhibit much lower adsorption energy for Pt atoms compared with the apical S²⁻ ligands on the terrace surface.

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