Improved catalytic activity in PdCo nanocatalysts synthesized via ultrasonic spray method for PEMFC applications

The current emphasis of research on PEM fuel cells is the exploration of novel, resilient, and very efficient electrocatalysts that do not rely on platinum, while also ensuring long-term stability. This study aimed to enhance the catalytic activity as cathode electrocatalysts by synthesizing Palladium-cobalt alloy nanoparticles using the ultrasonic spraying (US) technique and then dispersing them over a carbon black substrate. The ultrasonic spray method produces crystalline catalysts in the liquid-vapor interface reaction without requiring additional energy. Analyses were performed using XRD, SEM, EDS, XPS and TEM to determine the structural and morphological properties of the nanocatalysts. XRD analysis determined the average particle size of USCo–Pd/C and US-CoPd/C nanocatalysts to 1.37 nm and 1.09 nm, respectively. CV measurements identified ECSA values for USCo–Pd/C and US-CoPd/C as 7.1 m²/g_Pd and 8.9 m²/g_Pd. The relative performance ranking of cathode electrocatalysts for PEM fuel cells was evaluated at a cell temperature of 70 °C. The order of reactivity for the catalysts is as follows: US-CoPd/C > USCo–Pd/C > PdCo/C > Pd/C. The better electrochemical performance of USCo–Pd/C and US-CoPd/C nanocatalysts as cathode catalysts in PEM fuel cell applications, in comparison to Pd/C and PdCo/C catalysts, can be attributed to the modification of the electronic structure of palladium. This modification depends on the synthesis of cobalt and palladium metals together using the US method and the synergistic effect of the catalysts.