Electrochemical and photo-electrochemical properties of carbon spheres prepared via chemical vapor deposition

A noncatalytic chemical vapor deposition method was used to prepare graphitized carbon spheres (CSs) from acetylene. The CSs (diameter of 115±10 nm) with n type conductivity were found to be photo-electrochemically active with a diffuse reflectance spectrum band gap of 1.01 eV. The electrical conductivity followed an Arrhenius type law with an activation energy of 0.53 eV. From the capacitance measurements, the flat band potential (Vfb=−0.75VSCE) and the electron density (ND=3.46×1015 cm−3) were determined.