Enhanced OER properties from nanocomposites of Co3O4 and MOF derived N/S/Zn-doped porous carbon

In the present work, Co3O4 nanoparticles embedded in N/S/Zn- doped porous carbon matrices are synthesized and utilized as active materials to modify the commercial glassy carbon electrode (GCE) for enhanced and highly stable oxygen evolution reaction (OER). To design these nanocomposites, initially, a metal-organic framework (spherical ZnDTO) is synthesized by the complexation of Zn-salts and dithiooxamide (DTO) ligand, and N/S/Zn- doped porous carbon matrix (NSC) derived by carbonizing them at different temperatures. Then, to investigate the role of Zn on the catalytic performance of the materials, the thermally optimized carbon matrix is treated with a suitable acid. Further, hydrothermally synthesized Co3O4 nanoparticles are being used to form composites with these carbon matrixes. All the as-synthesized materials have been well-characterized by various tools for their structural and morphological associations. The best composite shows the onset overpotential of 480 mV vs. RHE close to 'RuO2' (460 mV vs. RHE) and has the lowest Tafel slope 62 mVdec−1. It excels in its current stability test for 7200 seconds at a static overpotential of 480 mV vs. RHE. It also exhibits continuous OER performance with a 130% increment in LSV current that reveals the catalyst's porous and non-corrosive nature. Finally, it has been proved with a thorough analysis that increased oxygen vacancies in the as-synthesized material are the protagonist to enhance the OER performance. At the same time, heteroatoms (N and S- atom) and Zn are also observed to enhance the electrocatalytic activity significantly.