Pd Nanoparticles on Carbon Supports as Electrocatalysts for the Oxygen Reduction Reaction

Abstract

The development of efficient catalysts for proton exchange membrane fuel cells (PEMFCs) is crucial for their commercial viability. This study introduces a method for synthesizing Pd nanoparticles on carbon supports as electrocatalysts using microbial synthesis, specifically employing the bacterium Shewanella oneidensis MR-1. The so-produced catalysts exhibit enhanced catalytic activity and stability for the oxygen reduction reaction (ORR). The microbial synthesis approach offers advantages, such as high purity, cost-effectiveness, and environmental friendliness. Additionally, the use of sodium alginate (SA) hydrogel in the synthesis process further improves the catalyst's performance due to its metal chelating properties. The resulting Pd/C electrocatalysts, especially those synthesized with a composite matrix of SA and CaCO 3 , demonstrate superior ORR performances outperforming that of commercial Pd/C catalysts. It was found that the composite substrate affected the palladium recovery rate, whose increasing palladium absorption, refined particle size, improved graphitization degree, and increasing pyridinic-N of the resultant catalyst synergistically enhanced the availability of active centers that eventually contributed to the superior ORR performances. This research paves the way for the development of highperformance and cost-effective catalysts for PEMFCs.

One-Pot Synthesis of Pd Nanoparticles Supported on Carbide-Derived Carbon for Oxygen Reduction Reaction

“…Various synthesis methods for PdNP preparation have been studied, which include methods such as microbial and other green methods using plant extracts; however, these methods are rather gimmicky and rarely produce suitable particle size for ORR application [20][21][22][23][24][25][26]. In order to obtain any reasonable mass activity for ORR then the noble metal particle size must be below 5 nm, but the number of synthesis methods for achieving these small particles is limited.…”

One-Pot Synthesis of Pd Nanoparticles Supported on Carbide-Derived Carbon for Oxygen Reduction Reaction

“…Various synthesis methods for PdNP preparation have been studied, which include methods such as microbial and other green methods using plant extracts; however, these methods are somewhat impractical and rarely produce suitable particle sizes for ORR application [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. The noble metal particle size must be below 5 nm to obtain any reasonable mass activity for ORR.…”