Efficient noble metal nanocatalysts supported on HfC(001) for O2 dissociation

Shiyan Wang,Zongxian Yang,Jianjun Mao,Yanxing Zhang,Xilin Zhang

doi:10.1063/1.4978267

Abstract

The adsorption and dissociation of O2 on the M4 (M=Au, Pd, Pt) clusters supported on HfC(001) (Hafnium Carbide) are investigated using ab initio density functional theory calculations. The geometric and electronic structures are analyzed in detail. It is found that the dissociation barriers of O2 on Au4/HfC(001) (0.26 eV), Pd4/HfC(001) (0.49 eV) and Pt4/HfC(001) (0.09 eV) are much smaller than those on the clean surfaces of HfC(001) (1.60 eV), Au(111) (1.37 eV), Pd(111) (1.0 and 0.91 eV) and Pt(111) (0.27–0.7 eV), respectively. The low dissociation barriers imply that the Pt4/HfC(001) exhibits the highest catalytic activity for O2 dissociation, and the Au4/HfC(001) and Pd4/HfC(001) may also be possible substitutes with lower cost for the current Pt/C catalyst for O2 dissociation. The present study is conductive to designing new efficient noble metal catalyst using HfC support for efficiently promoting O2 dissociation.

Highlights

Due to many recent issues such as a rapid increase in electrical energy demand, shortage of conventional fuels and environmental issues,[1] fuel cells are receiving considerable focus both in industry and science.[2]
The Mulliken analysis shows that the most noticeable charge transfer from the HfC(001) surface to the metal clusters happens on Pt4/HfC(001) (0.28 e per Pt atom), which is followed by Pd4/HfC(001) (0.24 e per Pd atom) and Au4/HfC(001)
Our results are consistent with the theoretical studies of Gomez et al.[50] which showed that the charge transfer follows the trend of the adhesion energy of M4 clusters on the TiC(001) surface

Summary

INTRODUCTION

Due to many recent issues such as a rapid increase in electrical energy demand, shortage of conventional fuels and environmental issues,[1] fuel cells are receiving considerable focus both in industry and science.[2]. It is expected that the low coverages of noble metal clusters supported on TMCs(001) would reduce the use of the precious metal and has high catalytic activity for ORR. In this contribution, we investigate the adsorption and dissociation mechanisms of O2 on the surfaces of HfC(001) and M4/HfC(001) (M=Au, Pd, Pt) using DFT calculations.

THE MODELS AND CALCULATION DETAILS

RESULTS AND DISCUSSION

SUMMARY AND CONCLUSIONS