Three-dimensional porous g-C3N4 nanosheet, CNT and ZIF-8@ZIF-67-derived carbon nanoarchitecture composite as oxygen reduction electrocatalyst

In response to the pressing need for high-performance, non-precious metal-based electrocatalysts to address energy crises and mitigate the drawbacks of fossil fuels, we introduce an innovative approach to develop a highly selective and competitive MOF-derived electrocatalyst for the reduction of oxygen (ORR). This electrocatalyst leverages the unique properties of cobalt (Co), graphitic carbon nitride (GCN or g-C3N4), and carbon nanotubes (CNTs) through a straightforward hydrothermal synthesis method. The incorporation of cobalt enhances electron transfer kinetics, while the porous structure of GCN and the tubular morphology of CNT collectively amplify the available surface area, facilitating ORR. The synergy arising from these constituents (Co, GCN, & CNT) promotes catalytic reactions, benefitting from their distinct morphological features, abundant heterojunction interfaces, and structural robustness. XRD, FESEM, TEM, EDX, FTIR, Raman, as well as electrochemical tests such as CV, LSV, chronoamperometry, and EIS were employed to characterize the synthesized electrocatalysts and evaluate their electrocatalytic activity for ORR. Two distinct samples, denoted as Co@NC/GCN50-CNT20 and Co@NC/GCN20-CNT50, exhibit excellent electrocatalytic activity toward ORR, characterized by impressive onset potentials of-0.07 and-0.09 V vs. Ag/AgCl, respectively. Notably, these two samples demonstrate a diffusion- limited current density of-8.5 and-8.4 mA cm- 2 . Furthermore, these materials exhibit exceptional stability, surpassing that of commercial Pt/C catalysts, making them promising candidates for a sustainable energy future.