CTAB-reduced synthesis of urchin-like Pt–Cu alloy nanostructures and catalysis study towards the methanol oxidation reaction

Abstract

Urchin-like PtCu alloy nanostructures were fabricated using a facile co-reduction approach, and the cationic surfactant cetyltrimethylammonium bromide (CTAB) served as the reducing agent. The reaction temperature highly influenced the reducing activity of CTAB, and no reducing activity was exhibited when the reaction temperature was below 120 °C. During the formation process of urchin-like PtCu alloy nanostructures, partial CTAB firstly reacted with H₂PtCl₆ to produce a yellow colloid precipitation, which could reduce the generation rate of Pt atoms and benefit the alloying of Cu with metallic Pt to form the PtCu alloy. Compared with pure Pt, the PtCu alloy catalyst exhibited a much higher catalytic efficiency and stability towards the methanol oxidation reaction. It was proposed that the enhanced catalytic activity of the PtCu alloy was attributed to the downshift of the d-band center of Pt, which greatly reduced the affinity energy with CO* intermediate species.