Structural and electronic properties of the adsorption molecules on Co and Fe/N-doped graphene towards the application i
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ORIGINAL RESEARCH
Structural and electronic properties of the adsorption molecules on Co and Fe/N-doped graphene towards the application in direct liquid fuel cell N. A. Karim 1
&
N. S. Shamsul 1 & M. S. Alias 1 & S. K. Kamarudin 1,2
Received: 13 December 2019 / Accepted: 8 September 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Co and Fe-nitrogen-doped graphene model (MN4) with an N/C ratio of 0.043 is tested for oxygen reduction reaction. The models and calculations were done using density functional theory (DFT). Four molecules, namely O2, OOH, OH, and H2O2, are adsorbed on the Co and Fe atom of MN4, and the changes in the adsorption energy are compared with the graphene model with MN4 model with the N/C ratio of 0.051. With the exception of the FeN4-OO complex, the adsorption energy for molecules in MN4 increases when the ratio is changed. Other molecules such as methanol, carbon monoxide, ethanol, formic acid, and glycerol also have been tested for adsorption on the Co and Fe atom to study its potential for the reaction using these catalyst models. The results show that these models display little positive activities for the oxidation reaction at anode direct liquid fuel cell (DLFC) as alternative energy. The competitive reaction may occur in DLFC if these catalysts are used as cathode catalyst in DLFC. Both models have a high potential to proceed with H2O production in the oxygen reduction reaction. Furthermore, these model catalysts may also suitable for polymer electrolyte membrane fuel cell (PEMFC) if pure hydrogen is used as fuel. Keywords Direct liquid fuel cell . Cathode catalyst . Co and Fe/N-doped . DFT . Alternative energy
Introduction The oxygen reduction reaction (ORR) is a sluggish reaction in fuel cells and reduces the direct liquid fuel cell (DLFC) performance. The ORR produces water as the main product or/ and hydrogen peroxide as the by-product. The production of hydrogen peroxide is undesirable because it can destroy the chemical bonds of the electrolyte membrane. The nitrogendoped graphene, which contains a similar N4 structure in macrocycles, has been shown to be promising for use as the non-platinum catalyst in DLFCs. The addition of a metal such Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11224-020-01636-3) contains supplementary material, which is available to authorized users. * N. A. Karim [email protected] 1
Fuel Cell Institute, Universiti Kebangsaan Malaysia, UKM, 43600 Bangi, Selangor, Malaysia
2
Department of Chemical Engineering, Universiti Kebangsaan Malaysia, UKM, 43600 Bangi, Selangor, Malaysia
as iron (Fe) and cobalt (Co) in nitrogen-doped graphene generates Co and Fe/nitrogen-doped graphene (MN4). The MN4 catalyst has several nitrogen oxidation states such as pyridinic-N, pyrrolic-N, quaternary-N, and oxidized pyridinic-N [1]. The atomic composition of these nitrogen oxidation states depends on how the synthesis affects the molecular state of the MN4. The high nitrogen oxi
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