Preparation and characterization of nano-sized Pt–Ru/C catalysts and their superior catalytic activities for methanol and ethanol oxidation

Abstract

Carbon-supported PtRu nanoparticles (Ru/Pt: 0.25) were prepared by three different methods; simultaneous reduction of PtCl(4) and RuCl(3) (catalyst I) and changing the reduction order of PtCl(4) and RuCl(3) (catalysts II and III) to enhance the performance of the anodic catalysts for methanol and ethanol oxidation. Structure, microstructure and surface characterizations of all the catalysts were carried out by X-ray diffraction (XRD), transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The results of the XRD analysis showed that all catalysts had a face-centered cubic (fcc) structure with different and smaller lattice parameters than that of pure platinum, showing that the Ru incorporates into the Pt fcc structure by different ratios in all the catalysts. The typical particle sizes of all catalysts were in the range of 2-3 nm. The most active and stable catalyst for methanol and ethanol oxidation is catalyst III, in which a large amount (more than 90%) of PtRu alloy formation was observed. It has been found that this catalyst is about 8.0 and 33.4 times more active at ∼0.60 V towards the methanol and ethanol oxidation reactions, respectively, compared to the commercial Pt catalyst.

Electrochemical Design of Mesoporous Pt–Ru Alloy Films with Various Compositions toward Superior Electrocatalytic Performance

“…The higher binding energy at about 465.8 eV was assigned to oxidized Ru species with an oxidation state IV 55. 56…”

Facile Synthesis of Nanoporous Pt–Ru Alloy Spheres with Various Compositions toward Highly Active Electrocatalysts

“…As shown in Figure S4 in the Supporting Information, the XPS spectra of Pt–Ru alloys have two peaks centered at around 461 and 483 eV, which can be assigned to the Ru 3p 3/2 and Ru 3p 1/2 , respectively. The Ru 3p 3/2 signal was deconvoluted into two peaks at 465.8 and 462.1 eV, which are attributed to Ru and RuO 2 respectively 41. This shows that 92 atomic % of Ru in Pt 95 Ru 5 and 90 atomic % of Ru in Pt 91 Ru 9 were in their zero‐valent metallic state.…”

In Situ X-ray Absorption Spectroscopy Studies of Nanoscale Electrocatalysts

“…However, all these electrochemical reactions experience severe sluggish reaction kinetics, so electrocatalysts are necessary to improve the efficiency. In recent years, nanoscale catalysts have shown great advantages to catalyze electrochemical reactions due to their high surface area, tunable morphology, and a large amount of active sites [11][12][13][14]. For example, Zhou et al demonstrated that a hollow nanospheres with mesoporous N-doped carbon shells and well-dispersed Fe 3 O 4 nanoparticles can exhibit much higher ORR catalytic activity and better electrochemical durability than commercial Pt/C [15].…”