Surface Chemical Properties of Mo₂C, W₂C, Mo₂N and W₂N Probed with CO, CO₂and O₂ Adsorption: A DFT Analysis

Authors

Jingyun YE, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA;
Tianyu ZHANG, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA;
Lingyun XU, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA;
Shuxia YIN, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA;
Krishanthi WEERASINGHE, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA;
Pamela UBALDO, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA;
Ping and GE Qingfeng HE, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA;

Corresponding Author

GE Qingfeng

Abstract

Transition metal carbides and nitrides are attractive materials for electrodes in many electrochemical energy storage and conversion applications. In the present study, we use density functional theory slab calculations to characterize the surface chemical properties of molybdenum (Mo) and tungsten (W) carbides and nitrides, namely, Mo₂C, W₂C, Mo₂N and W2N with the adsorption of CO, CO₂ and O₂. These probing molecules provide measures of in both acidity/basicity and redox property of for the surfaces of these carbides and nitrides. Our results show that Lewis basic sites were responsible for CO₂ adsorption and the basicity follows followed an order of α-W₂C(001) > α-W₂N(001) > β-Mo₂C(001) > γ-Mo₂N(100). Both CO and O₂ adsorption provide measures of in the reducing ability of these carbides and nitrides. The results showed a reducing ability in the order of β-W₂C(100) > α-Mo₂C(100) > α-W₂N(001) > α-W₂C(001) > β-Mo₂C(001) > γ-Mo₂N(100). The reducing nature of these carbides and nitrides make them good candidates to substitute noble metals in various catalytic reactions.

Graphical Abstract

Keywords

Density functional theory, Transition metal carbides, Transition metal nitrides, Redox sites, Acidity/basicity.

DOI Link

https://doi.org/10.13208/j.electrochem.170141

Publication Date

2017-08-25

Online Available Date

2017-02-21

Revised Date

2017-02-10

Received Date

2017-01-05

Recommended Citation

Jingyun YE, Tianyu ZHANG, Lingyun XU, Shuxia YIN, Krishanthi WEERASINGHE, Pamela UBALDO, Ping and GE Qingfeng HE. Surface Chemical Properties of Mo₂C, W₂C, Mo₂N and W₂N Probed with CO, CO₂and O₂ Adsorption: A DFT Analysis[J]. Journal of Electrochemistry, 2017 , 23(4): 371-380.
DOI: 10.13208/j.electrochem.170141
Available at: https://jelectrochem.xmu.edu.cn/journal/vol23/iss4/2