Nitrogen-Doped Oxygenated Molybdenum Phosphide as an Efficient Electrocatalyst for Hydrogen Evolution in Alkaline Media.

Muhammad Waqas Khan,Rizwan Ur Rehman Sagar,Farjana Haque,Babar Shabbir,Nasir Mahmood,Rashad Ali,Ali Zavabeti,Md Mohiuddin,Asif Mahmood,Jian Zhen Ou,Yongkun Liu,Ahmed Alluqmani,Turki Alkathiri,Xian Jian,Suraj Loomba

doi:10.3389/fchem.2020.00733

Abstract

Phosphides of transition metals (TMPs) are a developing class of materials for hydrogen evolution reaction (HER) as an alternative to expensive noble metals to produce clean energy. Herein, the nitrogen-doped molybdenum oxide (MoOx) is developed via a facile and simple hydrothermal method, followed by annealing in the N2 atmosphere and phosphorization to form a nitrogen-doped oxygenated molybdenum phosphide (N-MoP) sphere-shaped structure. The developed N-doped phosphide structure depicts enhanced HER activity by reaching a current density of 10 mA cm−2 at a very low overpotential of only 87 mV, which is much better than annealed nitrogen-doped molybdenum oxide (A-MoOx) 138 mV in alkaline medium. N-MoP is a highly efficient electrocatalyst for HER attributed to a more exposed surface, large electrode/electrolyte interface and appropriate binding energies for reactants. This study extends the opportunity of developing nitrogen-doped TMPs, which can display exceptional properties as compared to their oxides.

Highlights

Excessive use of fossil fuels and other non-renewable energy sources has led to their fast depletion and the omnipresent issue of environmental pollution (Jiao et al, 2015; Yuan et al, 2016; Li et al, 2020)
Hydrogen evolution reaction (HER) is expected to provide a favorable pathway for inexpensive H2 generation, which can be used as an alternative fuel to fossil fuels (Turner, 2004; Zou and Zhang, 2015; Surendran et al, 2018, Surendran et al, 2019a)
Various other Mo-based compounds including carbides, borides, and nitrides were studied in the alkaline medium, but their use was hindered by poor stability and higher overpotentials (Haque et al, 2019)

Summary

Introduction

Excessive use of fossil fuels and other non-renewable energy sources has led to their fast depletion and the omnipresent issue of environmental pollution (Jiao et al, 2015; Yuan et al, 2016; Li et al, 2020). Experiments carried out by Xing et al (2014) resulted in the development of the closely linked networked structure of MoP nanoparticles, which showed the best HER performance with an overpotential of 125 mV to achieve a current density of 10 mA cm−2. There is a need to develop some nitrogen-doped MoPbased novel structures for an enhanced performance and stability in the alkaline medium.

Results

Conclusion