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Nano Research

Article Title

Oxygen vacancy engineering of calcium cobaltate: A nitrogen fixation electrocatalyst at ambient condition in neutral electrolyte

Authors

Xinyu Chen, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Ke Li, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Xiaoxuan Yang, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Jiaqi Lv, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Sai Sun, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Siqi Li, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Dongming Cheng, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Bo Li, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Yang-Guang Li, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
Hong-Ying Zang, Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China

Keywords

nitrogen fixation, oxygen vacancy, electrocatalysis, calcium cobaltate, nanoplates

Abstract

In order to sustainably transform N2 to ammonia (NRR) using electrocatalysts under mild ambient condition, it is urgent to design and develop non-nobel metal nanocatalysts that are inexpensive and suitable for mass-production. Herein, a calcium metalate catalyst CaCoOx with oxygen vacancies was synthesized and used as an electrocatalyst for NRR for the first time, whose morphology can be controlled by the calcination temperature and the heating rate. Under the optimal conditions, the CaCoOx catalyst achieved the yield of nitrogen conversion to ammonia of 16.25 μg·h-1·mgcat.-1 at the potential of -0.3 V relative to the reversible hydrogen electrode (RHE) with a Faraday efficiency of 20.51%. The electrocatalyst showed good stability even after 12 times recyclability under environmental conditions and neutral electrolyte. Later, the electrocatalytic nitrogen reduction performance of CaFeOx, CaNiOx, CaCuOx was investigated. These earth-rich transition metals also exhibited certain NRR electrocatalytic capabilities, which provided a door for further development of inexpensive and easily available transition metal as nitrogen reduction electrocatalysts.

Publisher

Tsinghua University Press

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