Origin of the electrocatalytic activity in carbon nanotube fiber counter-electrodes for solar-energy conversion

摘要: Carbon nanotubes are a versatile platform to develop sustainable and stable electrodes for energy-related applications. However, their electrocatalytic activity is still poorly understood. This work deciphers the origin of catalytic counter-electrodes (CEs)/current collectors made self-standing carbon nanotube fibers (CNTfs) using Co2+/Co3+ redox couple electrolytes. based on comprehensive electrochemical spectroscopic characterization fresh used applied symmetric cells platinum-based CEs as reference. As most relevant findings, two straight relationships were established: (i) limiting current stability increase rapidly with surface concentration oxygen-containing functional groups, (ii) potential inversely related amount residual metallic Fe catalyst nanoparticles interspersed in CNTf network. Finally, fine tuning metal nanoparticle content degree functionalization enabled fabrication efficient dye-sensitized solar cobalt electrolytes CNTf-CEs outperforming those reference Pt-CEs.