Rice Straw Biochar as an Effective Support for Pd Nanoparticles for Ethanol Electro-Oxidation Reaction in Alkaline Condition

Herein, we report the utilization of biochar derived from rice straw (RSB) as an effective support matrix for Pd nanoparticles and its application as an electrocatalyst for ethanol electro-oxidation (EEO) in an alkaline medium. Rice straw, a common agricultural byproduct, was pyrolyzed at 600 degrees C, 700 degrees C, and 800 degrees C under N2 atmosphere. Pd was loaded onto the RSB via borohydride reduction of Pd2+, with a nominal loading of 20 % Pd. Spectroscopic and morphological characterization revealed the formation of dispersed Pd nanoparticles on the RSB surface. Pyrolysis temperature was observed to influence both the porosity of the resulting RSB and the dispersion and degree of exposure of Pd nanoparticles deposited on the surface. Electrochemical characterization revealed that Pd/RSB could be a potential EEO electrocatalyst for direct ethanol fuel cell applications. Pd/RSB-700 exhibited better performance in terms of EEO forward mass activity (jf) and forward and backward mass activity (jf/jb) ratio relative to Pd/RSB-600 and Pd/RSB-800. Moreover, Pd/RSB was shown to be superior to commercial Pd on carbon black in terms of electrochemical stability. This study opens the potential of rice straw biochar as a sustainable and environmentally friendly carbon-based support matrix for Pd-based EEO electrocatalysts.