Tin oxide species as promotive additives to Ni-P/C electrocatalysts for ethanol electro-oxidation in NaOH solution

Abstract

Incorporating transition metal oxide species in the chemical structure of nickel-based electrocatalysts was beneficial in improving their activity as anode materials in fuel cells. Electroless deposition technique was employed to synthesize Ni-P-SnO2/C composites containing variable wt% values of tin oxide species. Scanning electron micrographs revealed spherical nickel particles with diameter values ranging between 500 and 1100 nm. Elemental mapping images of these composites confirmed the presence of nickel, phosphorous, tin, oxygen and carbon in their structural composition. An enhanced performance of these Ni-P-SnO2/C electrocatalysts was measured during ethanol oxidation reaction in alkaline solution. The added SnO2 content in the prepared electrocatalysts was found to influence their electrocatalytic activity. The highest ethanol oxidation current density values were attained at electrocatalysts containing 2.5 or 25 wt% SnO2. Furthermore, chronoamperometry demonstrated their stable behavior over prolonged operation. The charge transfer properties of Ni-P-SnO2/C electrocatalysts were significantly affected by the chosen potential value, ethanol and NaOH concentrations.