Phosphorus-Mo 2 C@carbon nanowires toward efficient electrochemical hydrogen evolution: Composition, structural and electronic regulation

Zhangping Shi, Kaiqi Nie, Zheng Jiang Shao, Boxu Gao, Huanlei Lin, Hongbin Zhang, Bolun Liu, Yangxia Wang, Yahong Zhang, Xuhui Sun*, Xiao Ming Cao, P. Hu, Qingsheng Gao, Yi Tang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

242 Citations (Scopus)

Abstract

To explore high-performance electrocatalysts, electronic regulation on active sites is essentially demanded. Herein, we propose controlled phosphorus doping to effectively modify the electronic configuration of nanostructured Mo 2 C, accomplishing a benchmark performance of noble-metal-free electrocatalysts in the hydrogen evolution reaction (HER). Employing MoO x -phytic acid-polyaniline hybrids with tunable composition as precursors, a series of hierarchical nanowires composed of phosphorus-doped Mo 2 C nanoparticles evenly integrated within conducting carbon (denoted as P-Mo 2 C@C) are successfully obtained via facile pyrolysis under inert flow. Remarkably, P-doping into Mo 2 C can increase the electron density around the Fermi level of Mo 2 C, leading to weakened Mo-H bonding toward promoted HER kinetics. Further density functional theory calculations show that the negative hydrogen-binding free energy (ΔG H∗ ) on pristine Mo 2 C gradually increases with P-doping due to electron transfer and steric hindrance by P on the Mo 2 C surface, indicating the effectively weakened strength of Mo-H. With optimal doping, a ΔG H∗ approaching 0 eV suggests a good balance between the Volmer and Heyrovsky/Tafel steps in HER kinetics. As expected, the P-Mo 2 C@C nanowires with controlled P-doping (P: 2.9 wt%) deliver a low overpotential of 89 mV at a current density of -10 mA cm -2 and striking kinetic metrics (onset overpotential: 35 mV, Tafel slope: 42 mV dec -1 ) in acidic electrolytes, outperforming most of the current noble-metal-free electrocatalysts. Elucidating feasible electronic regulation and the remarkably enhanced catalysis associated with controlled P-doping, our work will pave the way for developing efficient noble-metal-free catalysts via rational surface engineering.

Original languageEnglish
Pages (from-to)1262-1271
Number of pages10
JournalEnergy and Environmental Science
Volume10
Issue number5
DOIs
Publication statusPublished - 19 Apr 2017
Externally publishedYes

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

Fingerprint

Dive into the research topics of 'Phosphorus-Mo <sub>2</sub> C@carbon nanowires toward efficient electrochemical hydrogen evolution: Composition, structural and electronic regulation'. Together they form a unique fingerprint.

Cite this