Fabrication of copper centered metal organic framework and nitrogen, sulfur dual doped graphene oxide composite as a novel electrocatalyst for oxygen reduction reaction

The main focus of this study is to synthesize a free platinum electrocatalyst for ORR applications. Since the price of copper is much lower than platinum, the Copper centered Metal Organic Framework (Cu MOF) is selected as the electrocatalyst. The electron conductivity of MOFs is low. Accordingly, in order to enhance the ORR kinetics and electrochemistry activity, for the first time, Nitrogen and Sulfur Dual Doped Reduced Graphene Oxide (NS RGO) with different concentrations are incorporated into the Cu MOF structure. In other words, NS-RGO has high electrical conductivity which can operate as an efficient carrier for electron transfer. For evaluating the structural properties and morphology of synthesized electrocatalysts, six main characterization techniques, consist of XRD, FESEM, Raman, EDS, TEM, and FTIR are employed. Also, in order to assess the durability and ORR activity, the electrochemical measurements are performed. The electrochemical tests are implemented using the Rotary Disk Electrode (RDE) device in the alkaline medium. Based on the achieved results, the best ORR activity is related to the 8% NS RGO Cu MOF catalyst. The onset potential and electron transferred number (n) of this catalyst are obtained to be-0.06 V vs Ag/AgCl and 3.53, respectively. In other words, it tends to favor the 4e-pathway for ORR. In this project, the relationship between structure and electrochemistry activity of non-precious metal/carbon composites is investigated. materials Finally, the electrochemistry activity of synthesized electrocatalysts is compared to the previous investigations and commercial 20 wt% Pt/C. These comparisons indicated that mixing different concentrations of NS-RGO with Cu-MOF can improve the electrochemistry activity of MOFs considerably. Actually, the NS RGO Cu MOF composite can be considered as a new cost-effective electrocatalyst that can help to the development of fuel cell technology. (c) 2020 Elsevier Ltd. All rights reserved.