Conductive diamond powder inclusion in drop-casted graphene for enhanced effectiveness as electrocatalyst substrate

The possibility of enhancing the electrochemical activity of multilayer graphene (GR) films formed by a simple drop-casting method by the inclusion of a moderate amount of boron-doped diamond powder (BDDP) into the immobilized active material was investigated. Raman spectroscopy experiments suggested that, for electrodes covered with GR-BDDP, edge planes of the graphene platelets are better exposed compared to the case of the GR-modified ones. Cyclic voltammetry measurements performed by using an outer-sphere redox system as test-compound demonstrated that BDDP addition results in an apparent electrocatalytic effect, which was ascribed (based upon the influence of the sweep rate on the voltammetric response) to a larger fraction of pores in the GR-BDDP coating, induced by its more loose morphological structure. The investigation of the methanol oxidation at the Pt-decorated electrodes demonstrated that the use of a GR-BDDP composite as support for the electrocatalyst facilitates the overall process, allows lower Tafel slopes and provides to the supported platinum a better resistance to fouling via CO-poisoning.