title: Coralloid Co2P2O7 Nanocrystals Encapsulated by Thin Carbon Shells for Enhanced Electrochemical Water Oxidation.
abstract: Core-shell nanohybrids containing cheap inorganic nanocrystals and nanocarbon shells are promising electrocatalysts for water splitting or other renewable energy options. Despite that great progress has been achieved, biomimetic synthesis of metal phosphates@nanocarbon core-shell nanohybrids remains a challenge, and their use for electrocatalytic oxygen evolution reaction (OER) has not been explored. In this paper, novel nanohybrids composed of coralloid Co2P2O7 nanocrystal cores and thin porous nanocarbon shells are synthesized by combination of the structural merits of supramolecular polymer gels and a controllable thermal conversion technique, i.e., temperature programmable annealing of presynthesized supramolecular polymer gels that contain cobalt salt and phytic acid under a proper gas atmosphere. Electrocatalytic tests in alkaline solution show that such nanohybrids exhibit greatly enhanced electrocatalytic OER performance compared with that of Co2P2O7 nanostructure. At a current density of 10 mA cm(-2), their overpotential is 0.397 V, which is much lower than that of Co2P2O7 nanostructures, amorphous Co-Pi nanomaterials, Co(PO3)2 nanosheets, Pt/C, and some reported OER catalysts, and close to that of commercial IrO2. Most importantly, both of their current density at the overpotential over 0.40 V and durability are superior to those of IrO2 catalyst. As revealed by a series of spectroscopic and electrochemical analyses, their enhanced electrocatalytic performance results from the presence of thin porous nanocarbon shells, which not only improve interfacial electron penetration or transfer dynamics but also vary the coordination environment and increase the number of active 5-coordinated Co(2+) sites in Co2P2O7 cores.
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.
authors: Yingxue
authors: Y
authors: Chang
authors: Key Laboratory for Organic Electronics and Information Displays, Institute of Advanced Materials, Nanjing University of Posts & Telecommunications , Nanjing 210023, P. R. China.|State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Solid State Microstructures, Nanjing University , Nanjing 210093, P. R. China.
authors: Nai-En
authors: NE
authors: Shi
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.
authors: Shulin
authors: S
authors: Zhao
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.
authors: Dongdong
authors: D
authors: Xu
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.
authors: Chunyan
authors: C
authors: Liu
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.
authors: Yu-Jia
authors: YJ
authors: Tang
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.
authors: Zhihui
authors: Z
authors: Dai
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.
authors: Ya-Qian
authors: YQ
authors: Lan
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.|State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Solid State Microstructures, Nanjing University , Nanjing 210093, P. R. China.
authors: Min
authors: M
authors: Han
authors: Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, P. R. China.
authors: Jianchun
authors: J
authors: Bao
keywords: carbon; cobalt phosphates; coordination environment and geometry; core−shell nanostructures; electrocatalysis; oxygen evolution reaction