Deposition and activity stability of Pt–Co catalysts on carbon nanotube-based electrodes prepared by microwave-assisted synthesis

Abstract

This work investigates the electrochemical activity and durability of bimetallic Pt–Co electrocatalysts on carbon nanotube (CNT) electrodes, which are prepared by using a microwave-assisted polyol process within a short period of ∼6 min. Multilayered CNTs are directly grown on carbon paper (CP) substrate by catalytic chemical vapor deposition with Ni catalyzing the growth of CNTs. The as-grown CNTs are employed as the support for the subsequent Pt–Co catalysts, which are deposited on the CNTs by using one- and two-step microwave-assisted reduction processes. Physicochemical characterizations are conducted to identify particle dispersion, particle-size distribution, and Pt/Co atomic ratio in the binary catalysts. It has been shown that Pt–Co–CNT/CP electrocatalyst, prepared by two-step microwave heating (i.e., deposition of Pt, followed by Co addition), offers highly electrochemical surface area and stable activity during potential cycling (1000 cycles). Such Pt–Co crystallographic phases on CNT-based support are found to be more corrosion-resistant in acidic electrolyte and represent the preferred phase structure under the consideration of activity stability. The fact that the microwave-assisted deposition of Pt–Co catalysts promotes electrochemical activity and stability has a great advancement on the development of binary electrocatalysts for fuel-cell applications.