Cobalt Phosphides Nanocrystals Encapsulated by P-Doped Carbon and Married with P-Doped Graphene for Overall Water Splitting

Jing Yang; Donghua Guo; Shulin Zhao; Yue Lin; Rui Yang; Dongdong Xu; Naien Shi; Xiaoshu Zhang; Lingzhi Lu; Ya-Qian Lan; Jianchun Bao; Min Han

doi:10.1002/smll.201804546

Cobalt Phosphides Nanocrystals Encapsulated by P-Doped Carbon and Married with P-Doped Graphene for Overall Water Splitting

Small. 2019 Mar;15(10):e1804546. doi: 10.1002/smll.201804546. Epub 2019 Jan 28.

Authors

Jing Yang¹, Donghua Guo¹, Shulin Zhao¹, Yue Lin², Rui Yang³, Dongdong Xu¹, Naien Shi³, Xiaoshu Zhang¹, Lingzhi Lu¹, Ya-Qian Lan¹, Jianchun Bao¹, Min Han^{1

4}

Affiliations

¹ Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, P. R. China.
² Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, P. R. China.
³ Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing, 210023, P. R. China.
⁴ State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Solid State Microstructures, Nanjing University, Nanjing, 210093, P. R. China.

PMID: 30690876
DOI: 10.1002/smll.201804546

Abstract

As one class of important functional materials, transition metal phosphides (TMPs) nanostructures show promising applications in catalysis and energy storage fields. Although great progress has been achieved, phase-controlled synthesis of cobalt phosphides nanocrystals or related nanohybrids remains a challenge, and their use in overall water splitting (OWS) is not systematically studied. Herein, three kinds of cobalt phosphides nanocrystals encapsulated by P-doped carbon (PC) and married with P-doped graphene (PG) nanohybrids, including CoP@PC/PG, CoP-Co₂ P@PC/PG, and Co₂ P@PC/PG, are obtained through controllable thermal conversion of presynthesized supramolecular gels that contain cobalt salt, phytic acid, and graphene oxides at proper temperature under Ar/H₂ atmosphere. Among them, the mixed-phase CoP-Co₂ P@PC/PG nanohybrids manifest high electrocatalytic activity toward both hydrogen and oxygen evolution in alkaline media. Remarkably, using them as bifunctional catalysts, the fabricated CoP-Co₂ P@PC/PG||CoP-Co₂ P@PC/PG electrolyzer only needs a cell voltage of 1.567 V for driving OWS to reach the current density at 10 mA cm^-2 , superior to their pure-phase counterparts and recently reported bifunctional catalysts based devices. Also, such a CoP-Co₂ P@PC/PG||CoP-Co₂ P@PC/PG device exhibits outstanding stability for OWS. This work may shed some light on optimizing TMPs nanostructures based on phase engineering, and promote their applications in OWS or other renewable energy options.

Keywords: cobalt phosphides; electrocatalysis; heteroatom-doped carbon or graphene; nanohybrids; overall water splitting.

Abstract

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