organic template-free synthesis of ni-zsm-5 nanozeolite: a novel catalyst for formaldehyde electrooxidation onto modified ni-zsm-5/cpe

a novel modified ni-zsm-5 nanozeolite was fabricated via an organic template-free hydrothermal route. the average particle size of ni-zsm-5 nanozeolite was calculated to be 85 nm by scanning electronic microscopy. then, carbon paste electrode (cpe) was modified by ni-zsm-5 nanozeolite and ni2+ ions were then incorporated to the nanozeolite matrix. electrochemical behavior of this electrode was investigated by cyclic voltammetry that exhibits stable redox behavior of ni(iii)/ni(ii) couple in alkaline medium. it has been shown that ni-zsm-5 nanozeolite at the cpe surface can improve catalytic efficiency of the dispersed nickel ions toward formaldehyde (hcho) electrocatalytic oxidation. the values of electron transfer coefficient, charge-transfer rate constant and the electrode surface coverage were obtained to be 0.49, 0.045 s−1 and 4.11×10−8 mol cm−2, respectively. also, the catalytic rate constant for hcho and redox sites of electrode and diffusion coefficient were found to be 9.064×103 cm3 mol−1 s−1 and 8.575 ×10−6 cm2 s−1, respectively.