Platinum nanoparticles decorated carbon nanofiber hybrids as highly active electrocatalysts for polymer electrolyte membrane fuel cells

Abstract

Increasing the efficiency of electrocatalyst is the key demand for the polymer electrolyte membrane fuel cells (PEMFC). To address the activity and performance challenges of commercial electrocatalyst, Pt/C, we introduce a new hybrid catalyst support for Pt nanoparticles. In this regard, combining or mixing specific type of carbon-based supports is a feasible strategy to increase catalyst utilization and performance. In the current study, Pt nanoparticles (NPs) were decorated on a new hybrid network, comprising of carbon nanofiber (CNF) and carbon black (CB), by means of a facile and efficient microwave (MW) assisted reduction method. All synthesized electrocatalysts were characterized to elucidate chemical and morphological structures. Then, the hybrid electrocatalysts were utilized as hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) electrocatalysts and their electrocatalytic activities were investigated by using cyclic voltammetry (CV) and linear sweep voltammetry (LSV), respectively. We found that the hybridization of CNF with CB substantially improved not only the electrocatalytic activity but also the fuel cell performance, which can be attributed to a consecutive conductive network, in which CB acts as a spacer, and synergistic effects between the CNF and CB. The hybrid electrocatalyst (Pt/CNF-CB with 50:50 wt%) showed a superior activity toward HOR and ORR while also offering exceptional fuel cell performance. That hybrid possessed the highest electrochemically active surface area (ECSA) compared with Pt/CNF and Pt/CB. In addition, the mass activity (at 0.80 V vs RHE) of the Pt/CNF-CB (50:50 wt%) is about 3.3 and 3.5 times higher than that of Pt/CNF and Pt/CB, respectively. Furthermore, that hybrid electrocatalyst exhibited enhanced fuel cell performance with 907 mW.cm−1 maximum power density. This work demonstrated that the CNF-CB supported Pt nanoparticles as electrocatalysts are extremely promising for fuel cell reactions.