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Experimental and Computational Investigation of Hydrogen Evolution Reaction Mechanism on Nitrogen Functionalized Carbon Nanotubes
Author(s) -
Tuomi Sami,
Pakkanen Olli J.,
Borghei Maryam,
Kronberg Rasmus,
Sainio Jani,
Kauppinen Esko I.,
Nasibulin Albert G.,
Laasonen Kari,
Kallio Tanja
Publication year - 2018
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201800479
Subject(s) - overpotential , catalysis , carbon nanotube , hydrogen , materials science , carbon fibers , nitrogen , chemical engineering , renewable energy , electrochemistry , nanomaterials , nanotechnology , chemistry , organic chemistry , composite number , composite material , electrical engineering , electrode , engineering
Designing earth‐abundant element based efficient and durable electrocatalysts for hydrogen evolution reaction (HER) is attracting growing attention as the renewable electricity supply sector urgently needs sustainable methods for storing energy. Nitrogen functionalized carbon nanomaterials are an interesting electrocatalysts option because of their attractive electrical properties, excellent chemical stability and catalytic activity. Hence, this study reports the HER mechanism on nitrogen functionalized few‐walled carbon nanotubes (N‐FWCNT). With this earth‐abundant element based catalyst 250 mV overpotential is required to reach 10 mA cm −2 current density and so its HER activity is comparable to other non‐noble metal catalysts, and clearly among the highest previously reported for N‐FWCNTs. To gain fundament insight on their functioning, computational analysis has been carried out to verify the effect of nitrogen and to analyze the reaction mechanism. The reaction mechanism has also been analyzed experimentally with a pH series, and both the methods suggest that the HER proceeds via the Volmer‐Heyrovský mechanism. Overall hydrogen surface coverage on N‐FWCNT is also suggested to affect the HER rate. Interestingly, in the studied structure, carbons in vicinity of nitrogen atoms, but not directly bound to nitrogen, appear to promote the HER most actively. Furthermore, durability of N‐FWCNTs has been demonstrated by operating a full electrolyzer cell for five weeks.