Electrochemical Hydrogen Evolution over Hydrothermally Synthesized Re-Doped MoS2 Flower-Like Microspheres.

Juan Aliaga,Gabriel Alonso-Núñez,Pablo Vera,Mario Farías,Luis Ballesteros,Eglantina Benavente,Juan Araya,Francisco Paraguay-Delgado,Julio Urzúa,Guillermo González

doi:10.3390/molecules24244631

Abstract

In this research, we report a simple hydrothermal synthesis to prepare rhenium (Re)- doped MoS2 flower-like microspheres and the tuning of their structural, electronic, and electrocatalytic properties by modulating the insertion of Re. The obtained compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Structural, morphological, and chemical analyses confirmed the synthesis of poorly crystalline Re-doped MoS2 flower-like microspheres composed of few stacked layers. They exhibit enhanced hydrogen evolution reaction (HER) performance with low overpotential of 210 mV at current density of 10 mA/cm2, with a small Tafel slope of 78 mV/dec. The enhanced catalytic HER performance can be ascribed to activation of MoS2 basal planes and by reduction in charge transfer resistance during HER upon doping.

Highlights

The use of hydrogen (H2 ) as fuel has gained significant importance
These results indicate that hydrogen evolution reaction (HER) of 14.7% Re-doped MoS2 sample proceeds via a Volmer–Heyrovsky mechanism, where a proton fast discharge is followed by a rate-limiting electrochemical desorption step [36]
It has been found that hydrothermal synthesis of MoS2 doped with Re induces 2H-1T phase transformation [18], we cannot identify this phase transformation in our results due to special features of MoS2 synthesized under solvothermal conditions

Summary

Introduction

Hydrogen is a source of clean energy obtained at convenient cost by the water electrolysis process [1,2] This process has proven to be one of the most efficient methods for hydrogen production; the use of high-cost and scarce precious metal (Pt, Pd) materials, which have excellent electrocatalytic performances, hinders their large-scale application. In this context, several earth-abundant catalytic alternatives have been investigated, including, for example, phosphide-based materials [3], transition metal monopnictides [4], metal carbides [5], and transition metal dichalcogenides [6], among others.

Methods

Results

Conclusion