Porous Pt–NiOx nanostructures with ultrasmall building blocks and enhanced electrocatalytic activity for the ethanol oxidation reaction

Abstract

Oxidized species on surfaces would significantly improve the electrocatalytic activity of Pt-based materials. Constructing three-dimensional porous structures would endow the catalysts with good stability. Here, we report a simple strategy to synthesize porous Pt–NiO_x nanostructures composed of ultrasmall (about 3.0 nm) building blocks in an ethanol–water solvent. Structure and component analysis revealed that the as-prepared material consisted of interconnected Pt nanocrystals and amorphous NiO_x species. The formation mechanism investigation revealed that the preformed amorphous compounds were vital for the construction of porous structure. In the ethanol oxidation reaction, Pt–NiO_x/C exhibited current densities of 0.50 mA cm_Pt⁻² at 0.45 V (vs. SCE), which were 16.7 times higher than that of a commercial Pt/C catalyst. Potentiostatic tests showed that Pt–NiO_x/C had much higher current and better tolerance towards CO poisoning than the Pt/C catalyst under 0.45 V (vs. SCE). In addition, the NiO_x species on the surface also outperformed an alloyed Ni component in the test. These results indicate that the Pt–NiO_x porous nanomaterial is promising for use in direct ethanol fuel cells.