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 H2 SO4 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.