In the process of developing an excellent active and stable Pt/C electrocatalyst for oxygen reduction reaction in fuel cells, metals are supported on heteroatom doped mesoporous carbon derived from natural resources. In this context, tamarind seeds are utilized to derive high surface area porous carbon for N heteroatom doping and followed by Pt deposition for oxygen reduction reaction (ORR) catalyst. The synthesis process involves optimization of temperature, N-content in the catalyst followed by Pt deposition by virtue of their electrochemical ORR behavior. The Pt/N-TC-1000 catalyst exhibits an outstanding activity and stability towards ORR even after 20,000 potential cycles. This is credited to the existence of N heteroatom in the matrix of carbon, where N acts as the linker between Pt and TC-1000 to avail the Pt-N and N-C chemical bonds in the Pt/N-TC-1000 catalyst. A peak power density of 800 mW cm ⁻² is attained while evaluating the catalyst performance in a H ₂ -O ₂ polymer electrolyte membrane fuel cell (PEMFC), at 70 °C and ambient pressure. The Pt/N-TC-1000 catalyst outpaces the commercial Pt/C with reference to fuel cell performance and stability. This is attributed to the high porous and corrosion resistive carbon support in combination with the strong Pt–N–C chemical bonds.

A Cu-based 1D coordination polymer (Cu-1D-CP), [Cu₃(bpy)₃(μ-OH)₂(μ-CO₃)₂]_n has been synthesized and examined for its oxygen reduction reaction (ORR) activity in O₂ saturated 0.1 M KOH medium. Single crystal XRD study indicated the presence of two different Cu centers, mononuclear and binuclear, in Cu-1D-CP. Cu-1D-CP was supported on Ketjenblack carbon (Cu-1D-CP/C) to impart required electronically conducting path up to the Cu-active centers. Immobilization of mononuclear and binuclear sites was achieved by coating Cu-1D-CP/C layer with Nafion ionomer. Based on cyclic voltammetry and density functional theory, it was inferred that carbon and mononuclear-Cu center to facilitate 2-electron reduction of O₂ into HO₂⁻ and binuclear-Cu centers to facilitate 4-electron reduction of O₂. Complete reduction of O₂ by the latter is due to efficient overlap of HOMO of the binuclear site with the LUMO of O₂ molecule in side-on and bridging modes of O₂ adsorption. Even after 500 cycles of CV in O₂ saturated 0.1 M KOH electrolyte, the ORR activity of the Cu-1D-CP nearly unaffected indicating presence of stable Cu-active sites under the coulostatic stabilization of Nafion.