High efficient oxygen reduced reaction electrodes by constructing vertical graphene sheets on separated papillary granules formed nanocrystalline diamond films

Constructing more efficient air/solid/solution tri-interface for carbon-based oxygen reduced reaction (ORR) electrodes and evaluating the effects of layer numbers of graphene supporter loaded with defects on ORR performance are never explored before. We have successfully assembled vertical graphene sheets (VGs) with edge defects as catalyst centers on separated papillary granules formed (SPF) nanocrystalline diamond films (NCD) and firstly prepared high hydrophobic and high sticky carbon-based electrodes with highly efficient ORR performance. The results show that we regulate the VGs from lying to erect, providing hydrophobic surface to super-hydrophobic surface with high sticky. As the surfaces with medium static contact angle (SCAs)(130 degrees similar to 140 degrees) and high stickiness produce appropriate negative pressure to drag enough electrolyte to soak the VGs and still leave air pockets among SPF to form quantities of air/solid/liquid tri-interface, the VG-on-SPF-NCD electrodes possess better ORR performance. We firstly combine the I-D', I-2D/I-G and FWHM2D values from Raman spectra to express the defects loaded on fewer layers of graphene. It is a more precise way to assess the ORR catalytic active defects on carbon materials. Our results supply a simple way to construct catalytically active VGs on SPF nanocrystalline diamond films. (C) 2020 Published by Elsevier Ltd.