Porous carbon from ZnCl2-activated biomass: Catalytic performance and structural insights in ORR

Abstract

The advancement of metal-air battery and fuel cell technologies depends on finding out of oxygen reduction reaction (ORR) catalysts with higher efficiency. The RH-900/ZnCl₂ catalyst, which is activated by ZnCl₂ and produced from biomass, shows superior ORR activity compared with commercial Pt/C catalysts, with half-wave potentials of 0.89 V. Nanoparticles of ZnO and SiO₂ as well as nitrogen doping, combined with the porous carbon structure, produce this improved performance. The combination enhances the ORR's active site density and enhances electron transfer efficiency. Function groups that facilitate proton transfer and structural stability are shown by Raman spectroscopy and Fourier transform infrared studies, which also show an excellent combination of ordered graphitic and disordered carbon structures and BET analysis confirms a high porous surface area of 1134.82 m²/g. Important for enhancing conductivity and catalytic activity, XPS studies reveal the existence of silicon, oxygen, zinc, and nitrogen species. FE-SEM and HRTEM analyses reveal a carbon matrix that is extremely porous and contains ZnO and SiO₂ nanoparticles that are uniformly distributed. Based on the results of the electrochemical tests, RH-900/ZnCl₂ is the best ORR catalyst easily accessible with superior stability and resistance to methanol poisoning compared with RH-900 and commercial Pt/C catalysts. These features placed RH-900/ZnCl₂ unique as a potential long-term replacement for standard Pt-based catalysts in ORR applications within energy conversion and storage devices.