Zn-induced defect engineering to activate bimetallic NiCo alloy@nitrogen-doped graphene hybrid nanomaterials for enhance
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Zn-induced defect engineering to activate bimetallic NiCo alloy@nitrogen-doped graphene hybrid nanomaterials for enhanced oxygen reduction reaction Bo Zheng1,* , Yue Zhou1, Chuan Yu1, Shaoxian Liu1, Zhaorui Pan1, Xiaofeng Wang1, Guangxiang Liu1,*, and Leiming Lang1,* 1
Key Laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, China
Received: 19 April 2020
ABSTRACT
Accepted: 9 August 2020
Developing valid strategies to fabricate highly active non-platinum-group metal electrocatalysts for catalyzing the sluggish cathode oxygen reduction reaction (ORR) is urgently required. To our knowledge, the catalytic performance of heterogeneous catalysts is highly related to their electronic and architectural properties. Defect or vacancy engineering is a particularly attractive means of modifying the physicochemical properties of nanomaterials. Herein, in this work, we proposed a facile Zn-induced defect strategy to engineer the electronic and surface structure of non-noble bimetallic NiCo alloy@nitrogen-doped graphene hybrid nanomaterials for boosting ORR activity. The optimized sample shows prominently enhanced activity for the ORR in KOH solution and exhibits better stability and methanol tolerance compared to Pt/C. Physicochemical and electrochemical measurements demonstrate that the enhanced ORR performance is mainly ascribed to the proper Zn-induced vacancy defects, which finely modulate the energy level of electrocatalyst, thus activating ORR process thermodynamically. Moreover, rich exposed active sites from vacancy defects largely facilitate the sluggish kinetics. This strategy is exceptionally promising to be applied to optimize other non-noble metal-based nanomaterials for highly efficient electrocatalysis.
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
Introduction Currently, energy shortage and environmental pollution around the world requires people to vigorously develop sustainable energy technologies. Fuel cells and metal–air batteries are considered as
promising renewable energy devices. Three fundamental electrochemical processes occur on electrode surfaces: hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). A variety of catalysts have been proposed to accelerate these processes [1–5]. Unfortunately, the severely sluggish cathode ORR process
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https://doi.org/10.1007/s10853-020-05102-7
J Mater Sci
seriously impedes the widespread use. Therefore, the great challenges are confronted with selecting easily accessible, cost-effective and highly efficient electrocatalysts to conquer the issue. Among them, transition metals and their derivatives as the promising candidates have attracted tremendous attention. For transition metals, as illustrated by the classic volcano-shaped plot between the ORR activity and the oxygen adsorption energy [6], the catalysts with moderate adsorption energy o
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