Epitaxial Graphene Nanowalls As Electrocatalysts Supports for Electrocatalytic Reactions

Graphene-based materials, as promising supports for electrocatalysts, attract lots of attention due to its good conductivity, high surface area and chemical stability. However, the influence of such support to the behavior of the catalyst still lacks a unified understanding. Herein, we report, for the first time, a systematic study on the strain effect of substrate toward the catalysts. In this study, we fabricated epitaxial graphene nanowalls (EGNWs) with controllable strain (from tensile, EGNWs-T, to compressive, EGNWs-C) by taking advantages of microwave plasma enhanced chemical vapor deposition, and Pt nanoparticles deposited on EGNWs by RF magnetron sputtering systems, denoted as Pt/EGNWs. It is worth noting that the catalytic properties of Pt on methanol oxidation reactions are highly dependent on the strain of graphene substrates. The catalytic properties of Pt/EGNWs-T shows 100 times higher than that of Pt/EGNWs-C, and the mass activity of Pt/EGNWs-T is 876 A/g, which is almost 10 times higher than that of commercial Pt/C catalysts. In addition to catalytic properties, XANES analysis also gave clear understanding on the electronic state of Pt. We believed that EGNWs provides an excellent opportunity to improve the performance of catalysts by applying different strain on catalysts supports.