Electrochemically modified boron-doped diamond electrode with Pd and Pd-Sn nanoparticles for ethanol electrooxidation

The modification of hydrogen terminated boron-doped diamond (HBDD) electrode with pure palladium (Pd) and Pd-Sn (tin) nanoparticles is described in this study. For synthesis of Sn/HBDD and Pd-Sn/HBDD electrode, a potentiostatic two-step electrochemical method involving the electrodeposition of Sn followed by Pd was used, respectively. The modification of the HBDD electrode with Sn and noble metal Pd by forming bimetallic Pd-Sn nanoparticle leads to a higher electrocatalytic activity. The electrocatalytic activity of the bimetallic Pd-Sn nanoparticles was evaluated towards the electrooxidation of ethanol in alkaline media and compared with that of the Pd nanoparticles alone. The bimetallic Pd-Sn nanoparticles modified HBDD electrode exhibits higher current densities and less poisoning effects during ethanol electrooxidation compared to Pd/HBDD. The proper tuning of the Pd loading on a foreign metal along with the surface termination effects of the BDD electrode plays a crucial role in achieving a high mass (4.26 × 10⁶ mA/g) and specific (12.37 mA/cm²) electrocatalytic activity of Pd towards ethanol electrooxidation. The aforementioned catalysts of this research possess a high poisoning resistance (I_f/I_b = 1.63) and stability towards ethanol electrooxidation in alkaline media.