A new attitude to environment: Preparation of an efficient electrocatalyst for methanol oxidation based on Ni-doped P zeolite nanoparticles synthesized from stem sweep ash

Graphical abstract: - Abstract: Amorphous silica powder was extracted from stem sweep (SS) which grows in the southern parts of the Caspian Sea (Mazandran province, Iran) and used in the preparation of P zeolite nanoparticles. X-ray diffraction, scanning electronic microscopy, transmission electron microscopy and FT-IR techniques were used to characterize P zeolite nanoparticles. SEM and TEM showed the presence of nearly spherical nanoparticles with sizes in the nanometer range. Ni²⁺ ions could introduced into the pores of P zeolite nanoparticles through exchange with Na⁺ ions to modify zeolite and improve their electrochemical properties. To surmount the overvoltage of methanol oxidation on carbon paste electrode (CPE), Ni (II)-doped P zeolite (Ni/P) mixed with CPE was used as modified electrode (Ni/P-CPE). Electrochemical techniques such as cyclic voltammetry and chronoamperometry were applied to modified electrode in order to investigate the role of zeolite in electrocatalytic process of methanol oxidation. The current intensity of methanol oxidation increases impressively on Ni/P-CPE in the presence of methanol and in comparison with CPE that means the catalyst can reduce the overvoltage of methanol oxidation. Ni/P nanoparticles provide the active sites on modified electrode to catalyze the oxidation of methanol in alkaline solution. Some parameters such as potential scan rates and methanol concentration investigated to describe the mechanism of catalysis of methanol oxidation on Ni/P. In contrast to some expensive materials such as noble metals, Ni-doped P zeolite play effective role in reduction of methanol oxidation overvoltage by some valuable advantage such as inexpensive and environmentally friend nature and simplicity of preparation