Respective influence of stoichiometry and NiOOH formation in hydrogen and oxygen evolution reactions of nickel selenides

Understanding the inherent activity of an electrocatalyst is an effective way of studying its optimization conditions for harvesting better performance. In this, we studied the inherent electrocatalytic activity of nickel selenide catalysts of three different stoichiometry such as Ni0.85Se, Ni3Se4 a...

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Bibliographic Details
Published in:Applied surface science 2019-09, Vol.487, p.1152-1158
Main Authors: Anantharaj, Sengeni, Subhashini, Elangovan, Swaathini, Karukkampalyam C., Amarnath, Thangavel S., Chatterjee, Shubham, Karthick, Kannimuthu, Kundu, Subrata
Format: Article
Language:English
Subjects:
Electrocatalysis
Hydrogen evolution
Nickel selenide
Oxygen evolution
Stoichiometry dependence
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Summary:Understanding the inherent activity of an electrocatalyst is an effective way of studying its optimization conditions for harvesting better performance. In this, we studied the inherent electrocatalytic activity of nickel selenide catalysts of three different stoichiometry such as Ni0.85Se, Ni3Se4 and NiSe2 in which the Se:Ni ration varies as 1.176, 1.333 and 2.0 respectively. The hydrogen evolution reaction (HER) of these catalysts was found to increase with the increasing Se:Ni ratio due to which NiSe2 turned out to be the better one among others. Interestingly, the oxygen evolution reaction (OER) of these catalysts showed a different trend irrespective of Se:Ni ratio where the ease of formation of NiOOH was found to control the kinetic current. Such influences of stoichiometry in HER and ease of NiOOH formation in OER had never been revealed before for nickel selenide system. Nickel selenides of different stoichiometry behave differently in HER and OER electrocatalysis based on their Se:Ni ratio and ease of formation of NiOOH respectively in acid and alkaline electrolytes. [Display omitted] •Phase and NiOOH formation dependent HER and OER activities in nickel selenides are found.•HER trend in acid was found to mainly depend on the Se:Ni ratio.•OER trend in alkali was found to mainly depend on the ease of formation of NiOOH.•NiSe2 and Ni3Se4 were found to the best phases for HER and OER respectively.
ISSN:0169-4332
1873-5584
DOI:10.1016/j.apsusc.2019.05.118