ACS applied materials & interfaces | 10 Oct 2019
J Swaminathan, AB Puthirath, MR Sahoo, SK Nayak, G Costin, R Vajtai, T Sharifi and PM Ajayan
To gain a constructive insight on the possible effect of doping on the electrocatalytic activity of the materials, a catalytic framework with a discrete distribution of dopants is an appropriate model system. Such system assures well-defined active centers, maximum atom utilization efficiency and hence enhanced selectivity, catalytic activity, and stability. Herein, a comprehensive investigation of the electrocatalytic activity of iron-doped cobalt oxide (Fe-Co3O4) nanosheets is presented. In order to understand the contribution of dopants, a series of materials with controlled doping levels are investigated. By a controlled iron inclusion into the structure of Co3O4, an apparent improvement of oxygen evolution reaction activity which is reflected in the decrease of 160 mV in the overpotential to reach the current density of 10 mA/cm2 is manifested. Additionally, it is shown that there exists an optimum doping content above which the catalytic activity is faded. The further investigation of the system with density functional calculations reveals that, along with the optimization of adsorption energy towards the reaction intermediates, substantial downshift of Fermi level and delocalization of the electron density is occurred on introducing iron ions into the structure.
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