Bio-silica as immediate support for platinum nanoparticles in oxygen reduction reaction electrocatalysis

This study addresses the challenge of platinum degradation due to carbon support corrosion in proton exchange membrane fuel cells (PEMFCs) by presenting an approach for the direct immobilization of Pt nanoparticles onto rice-husk-derived bio-nanosilica. This strategy aims to overcome limitations associated with traditional Pt/C catalysts, which suffer from carbon support oxidation and catalyst migration under operating conditions. The work describes the synthesis methodology for Pt/SiO2-C via amine functionalization of bio-nanosilica, followed by chemical reduction of platinum precursors and incorporation with conductive carbon materials to maintain electronic conductivity. The resulting Pt/SiO2-C1 (6:1) catalyst shows promising oxygen reduction reaction (ORR) activity with an onset potential of 0.87 V vs RHE at a low Pt loading of 3.3 wt.%, indicating good mass activity performance. Additionally, accelerated durability tests conducted under fuel cell operating conditions show improved kinetic activity and stability with a positive shift of 10 mV in half-wave potential after a 5000-cycle load test, suggesting better catalyst retention compared to conventional systems. This work explores a potential avenue for designing sustainable electrocatalysts for PEMFCs, addressing a materials challenge while utilizing renewable biomass-derived support materials. The approach shows promise for the development of more durable fuel cell catalysts with improved stability characteristics.