Ren Bin

Electrocatalytic Oxidation of Formic Acid on Pt-Se Hollow Nanosphere Modified Glassy Carbon Electrodes

National Natural Science Foundation of China [20663002]; Foundation of State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, China [200511]

In-situ surface-enhanced Raman spectroscopic investigation on ethanol electrooxidation in different media

Electrochemical voltametric methods and in-situ electrochemical surface-enhanced Raman spectroscopy (SERS)were used to investigate the electrooxidation behavior of ethanol in different media on a roughened platinum electrode.It was found that ethanol could dissociate spontaneously to produce strongly adsorbed intermediate,CO,in acidic,neutral,and alkaline media on the roughened platinum electrode.The complete oxidation potential of CO_(ad) on the roughened platinum electrode was negatively shifted about 0.300 V in the alkaline medium(0.20 V)compared with that in the acidic and neutral media(0.50 V).The positive oxidation peak potential of ethanol was negatively shifted about 0.85 V in the alkaline medium(-0.20 V)than that in the acidic medium(0.65 V).By comparing the oxidation current and the peak potential,it was found that the electrocatalytic activity of roughened platinum electrode for ethanol and CO oxidation in the alkaline medium was higher than in acidic and neutral media.The results suggested that ethanol was oxidized to CO_2 on the roughened platinum electrode via parallel reaction mechanism in acidic, neutral or alkaline media.

Platinum hollow nanospheres with different shell thickness： Controllable synthesis and electrocatalyst for the oxidation of formic acid

Pt hollow nanospheres with different shell thicknesses were synthesized by adjusting the amount of precursor H 2 PtCl 6 , using 120 nm of α -selenium colloids as the template, ascorbic acid as the reducing agent, and SDSN as stabilizing agent. The prepared platinum hollow spheres were drop-coated to modify the glassy carbon electrode (Pt hollow /GC) and used as the working electrode. Scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), energy dispersive X-ray spectrum (EDX), X-ray diffraction (XRD) and selected area electron diffraction (SAED) were used to determine the morphology and structure. The electrocatalytic oxidation behavior of formic acid on the modified electrodes was evaluated by cyclic voltammetry and chronoamperometry. The results show that the Pt hollow nanospheres have a uniform particle size and good dispersity. The shell of the spheres were made of Pt clusters of various size, showing the similar structure and propertie to that of the polycrystalline platinum. Hollow nanospheres showed different electrocatalytic activity on the oxidation formic acid at a different molar ratio between Se and Pt. The Pt hollow nanosphere with a molar ratio of 1:1.2 shows the highest activity, and is much more active than the electrodeposited Pt on glassy carbon surface. These provides theoretical and experimental conditions for the anode material of direct formic fuel cell, and has potential value of application.