Pt decorated 3D vertical graphene nanosheet arrays for efficient methanol oxidation and hydrogen evolution reactions

Abstract

Highly active and durable electrocatalysts are highly desirable for electrochemical energy conversion devices. Herein, we report the design and fabrication of Pt nanoplate decorated 3D vertical graphene nanosheet arrays supported on carbon cloth (Pt-VGNSAs/CC) as an integrated binder-free catalyst for both methanol oxidation and hydrogen evolution reactions (HER). The vertically aligned graphene nanosheets with large surface area and excellent conductivity provide an ideal support for dispersing the Pt nanoplates. As a result, the as-obtained Pt-VGNSAs/CC with optimized Pt loading exhibits significantly improved methanol electro-oxidation performance in terms of a high mass activity of 1050 mA mg⁻¹ and areal activity of 1.45 mA cm⁻², superior CO tolerance and reliable stability in contrast to those of commercial Pt/C catalysts. In addition, the Pt-VGNSAs/CC catalyst also shows promising electrocatalytic activity with a small onset potential of −60 mV vs. the RHE at 10 mA cm⁻², and a low Tafel slope of 28.5 mV dec⁻¹ as well as excellent long-term stability for the HER. The significantly enhanced electrocatalytic performance could be attributed to the structural advantages and strong synergistic effects between graphene and Pt.