TY - JOUR
T1 - Effect of Thermally Induced Oxygen Vacancy of α-MnO 2 Nanorods toward Oxygen Reduction Reaction
AU - Shi, X.
AU - Zheng, H.
AU - Mada Kannan, Arunachala
AU - Pérez-Salcedo, K.
AU - Escobar, B.
N1 - Funding Information:
The authors would like to thank CSIR, USAID (US-Pakistan Centers for Advanced Studies), and USAID (Global Development Research) for financial support. We acknowledge the use of facilities within the Eyring Materials Center at Arizona State University and XPS at LANNBIO Cinvestav Meŕ ida, Mexico.
Funding Information:
†Fuel Cell Laboratory, The Polytechnic School, Ira A. Fulton Schools of Engineering, Arizona State University, Mesa, Arizona 85212, United States ‡Energy Centre, Council for Scientific and Industrial Research (CSIR), Pretoria, Gauteng 0184, South Africa §Centro de Investigacioń Científica de Yucatań, Carretera Sierra Papacal − Chuburná Puerto, km 5. Sierra Papacal, Meŕ ida, C.P. 97302, Yucatań, Mex́ ico
Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/4/15
Y1 - 2019/4/15
N2 - MnO 2 has been explored for various applications in environmental and energy aspects. However, the thermal sensitivity of the MnO 2 crystal structure never been studied. As a potential cathode material for fuel cell, α-MnO 2 has a higher specific activity than Pt/C based on per metals cost. In this work, the physical and electrochemical properties of α-MnO 2 nanorods were explored for the first time under thermal treatment with different temperatures (300, 400, and 500 °C). Under thermal treatment, oxygen vacancies were induced. The high-angle annular dark-field (HAADF) images and electron energy loss spectroscopy (EELS) have been taken to explore oxygen vacancies of α-MnO 2 materials. From EELS and X-ray photoelectron spectroscopy (XPS) analysis, the oxygen vacancies on the α-MnO 2 nanorods were strengthened with the temperature increasing. The sample with 400 °C treatment exhibited the best performance toward ORR, excellent methanol tolerance and higher stability compared to commercial Pt/C in alkaline media due to its combination of preferable growth on (211) plane and moderate oxygen vacancies as well as coexistence of Mn (IV)/ Mn (III) species. It was also observed the α-MnO 2 nanorods tended to become longer and thinner with increasing temperature. This work suggests that the α-MnO 2 nanorods are thermal sensitive materials and their performance for ORR can be boosted under certain temperatures.
AB - MnO 2 has been explored for various applications in environmental and energy aspects. However, the thermal sensitivity of the MnO 2 crystal structure never been studied. As a potential cathode material for fuel cell, α-MnO 2 has a higher specific activity than Pt/C based on per metals cost. In this work, the physical and electrochemical properties of α-MnO 2 nanorods were explored for the first time under thermal treatment with different temperatures (300, 400, and 500 °C). Under thermal treatment, oxygen vacancies were induced. The high-angle annular dark-field (HAADF) images and electron energy loss spectroscopy (EELS) have been taken to explore oxygen vacancies of α-MnO 2 materials. From EELS and X-ray photoelectron spectroscopy (XPS) analysis, the oxygen vacancies on the α-MnO 2 nanorods were strengthened with the temperature increasing. The sample with 400 °C treatment exhibited the best performance toward ORR, excellent methanol tolerance and higher stability compared to commercial Pt/C in alkaline media due to its combination of preferable growth on (211) plane and moderate oxygen vacancies as well as coexistence of Mn (IV)/ Mn (III) species. It was also observed the α-MnO 2 nanorods tended to become longer and thinner with increasing temperature. This work suggests that the α-MnO 2 nanorods are thermal sensitive materials and their performance for ORR can be boosted under certain temperatures.
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U2 - 10.1021/acs.inorgchem.9b00492
DO - 10.1021/acs.inorgchem.9b00492
M3 - Article
C2 - 30907081
AN - SCOPUS:85063604432
SN - 0020-1669
VL - 58
SP - 5335
EP - 5344
JO - Inorganic chemistry
JF - Inorganic chemistry
IS - 8
ER -