Phosphate-assisted efficient oxygen evolution over finely dispersed cobalt particles supported on graphene

Feng Zeng, Jialin Li, Jan P. Hofmann, Timo Bisswanger, Christoph Stampfer, Heinrich Hartmann, Astrid Besmehn, Stefan Palkovits, Regina Palkovits (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)

Abstract

Electrochemical water splitting is a process to store renewable energy in hydrogen, which is a green energy carrier producing only water when combusted. However, the overall electrochemical water splitting is limited by the low efficiency of the anodic oxygen evolution reaction (OER) leading to a high overpotential. In this study, finely dispersed cobalt particles supported on graphene are prepared as an anodic catalyst and coupled with phosphate activation to enhance and stabilize OER activity. The small particles enable a high exposure of the surface active sites. Also, the highly conductive graphene backbone accelerates electron transport. Activation by phosphate in the electrolyte leads to the formation of the active Co(iii) species with enriched oxygen vacancies meanwhile facilitating the kinetics. The finely dispersed cobalt particles supported on graphene together with phosphate activation lead to high electrochemical surface area and intrinsic activity, achieving a current density of 10 mA cm−2at an overpotential of 0.35 V and a low Tafel slope of 45 mV per decade, together with good stability. The cobalt mass based current density is 19-8000 times higher than current benchmarking catalysts.

Original languageEnglish
Pages (from-to)1039-1048
Number of pages10
JournalCatalysis Science & Technology
Volume11
Issue number3
DOIs
Publication statusPublished - 7 Feb 2021

Funding

Feng Zeng acknowledges China Scholarship Council (CSC) for financial support. Regina Palkovits and Feng Zeng acknowledge the Federal Ministry of Education and Research (BMBF) for funding part of this work with the MANGAN research cluster (FKZ 03SF0508). Timo Bisswanger and Christoph Stampfer acknowledge funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 785219 (Graphene Flagship).

FundersFunder number
Horizon 2020 Framework Programme
Bundesministerium für Bildung und ForschungFKZ 03SF0508
China Scholarship Council
Horizon 2020785219

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