Ammonia gas sensing characteristics of V2O5 nanostructures: A combined experimental and ab initio density functional theory approach

被引：19

作者：

Akande, A. A. ^{[1
,2
]}

Mosuang, T. ^{[1
]}

Ouma, C. N. M. ^{[3
]}

Benecha, E. M. ^{[4
]}

Tesfamicheal, T. ^{[5
]}

Roro, K. ^{[6
]}

Machatine, A. G. J. ^{[7
]}

Mwakikunga, B. W. ^{[8
,9
]}

机构：

[1] Univ Limpopo, Dept Phys, P Bag X1106, ZA-0727 Sovenga, South Africa

[2] CSIR NextGen Enterprises & Inst, Adv Internet Things, POB 395, ZA-0001 Pretoria, South Africa

[3] North West Univ, HySA Infrastruct, Fac Engn, Private Bag X6001, ZA-252 Potchefstroom, South Africa

[4] Univ South Africa, UNISA, Sch Interdisciplinary & Grad Studies, ZA-0003 Pretoria, South Africa

[5] Queensland Univ Technol, Sci & Engn Fac, 2 George St, Brisbane, Qld 4000, Australia

[6] CSIR, R&D Core Energy, POB 395, ZA-0001 Pretoria, South Africa

[7] Univ Pretoria, Dept Phys, ZA-0002 Pretoria, South Africa

[8] Natl Ctr Nanostruct Mat, CSIR, DST, POB 395, ZA-0001 Pretoria, South Africa

[9] Tshwane Univ Technol, Dept Phys, POB 680, ZA-0001 Pretoria, South Africa

来源：

JOURNAL OF ALLOYS AND COMPOUNDS | 2020年 / 821卷

基金：

新加坡国家研究基金会; 芬兰科学院;

关键词：

alpha-V2O5; Para-to ferro-magnetic transition; NH3; adsorption; sensing; Electronic band gap; ELECTRONIC-STRUCTURE; VANADIUM PENTOXIDE; ADSORPTION; PERFORMANCE; V2O5(010); HYDROGEN; SURFACE; OXIDES; SENSOR;

D O I：

10.1016/j.jallcom.2019.153565

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

A combined experimental and density functional theory of alpha-V2O5 for ammonia gas sensing have been investigated. The material was synthesized from hydrated NH4VO3 in CVD at 400 degrees C in N-2 atmosphere for different time (12 h and 24 h). Highly crystalline orthorhombic alpha-V2O5 nano-rods with dominant (001) and (110) planes/facets nano-rods were observed from XRD, SEM and TEM characterizations. Using VSM technique, para-to ferro-magnetic transition was observed in the alpha-V2O5 nanoparticles synthesized at 24 h. Improved gas sensing was observed in case of the paramagnetic alpha-V2O5 nano-rods (nanoparticles synthesized at 12 h) compared with the one synthesized at 24 h. Additionally, significant rise in gas sensing response was observed around the metal to insulator transition temperature. Calculation of adsorption of NH3 molecule(s) on (001), (110), (200) and (400) facets showed that (001), (200) and (400) possessed more active sites than (110) surface. However, at higher concentration of NH3 molecules, the number of adsorbed molecules was found to be limited by the available adsorption sites in the case of (001) thereby causing the surface to be unstable. DFT calculations were also used to investigate NH3 adsorption on (110) surface of alpha-V2O5 with the analysis showing exponential decrease in the electronic band gap of the material's surface with the increasing numbers of NH3 loadings. (C) 2020 Elsevier B.V. All rights reserved.

引用

页数：9

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