Design and optimization of cobalt-encapsulating vertical graphene nano-hills for hydrogen evolution reaction

Sanjib Baran Roy, Sahng Kyoon Jerng, Kamran Akbar, Jae Ho Jeon, Linh Truong, Seung Hyun Chun, Min Jong Noh, Juho Lee, Yong Hoon Kim

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

In spite of its great potential for sustainable water splitting technology, many challenges remain for the development of effective graphene-based hydrogen evolution reaction (HER) electrocatalysts. Based on mutually corroborating growth, electrochemical measurements, and density functional theory (DFT) calculations, we herein develop the HER-active vertical graphene nano-hills (VGNHs) on Co thin films such that Co atoms are introduced into the VGNH tip region. The HER activity exhibits a volcano-shaped curve with respect to the encapsulated Co density, and the best performance achieved at the nominal Co substrate thickness of 1 nm is characterized by the low onset potential, overpotential, and Tafel slope in acidic electrolyte. Especially, with this low-cost yet structurally and chemically stable Co-seeded VGNH catalyst, a record-level mass activity is achieved. The emergence of the HER activity from the combination of originally HER-inactive VGNHs and Co thin films is clarified by DFT calculations, which identifies the synergistic effects of the nanoscale curvature at the VGNH tip and the charge-transfer doping by encapsulated Co atoms.

Original languageEnglish
Pages (from-to)17046-17052
Number of pages7
JournalJournal of Materials Chemistry A
Volume7
Issue number28
DOIs
StatePublished - 2019

Bibliographical note

Publisher Copyright:
© 2019 The Royal Society of Chemistry.

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