Effect of pH Value on Performance of PtRu/C Catalyst Prepared by Microwave‐Assisted Polyol Process for Methanol Electrooxidation

Abstract

PtRu/C catalysts with different mean particle sizes have been synthesised by microwave‐assisted polyol process at various pH values and characterised by transmission electron microscopy (TEM), energy dispersive analysis of X‐ray (EDAX) and X‐ray diffraction (XRD). Their electrochemical performances have been tested by cyclic voltammetry, amperomeric i–t, and CO‐stripping techniques. The effects of pH values on performances of the PtRu/C catalysts have been mainly investigated. It has been found that the particle size, composition and catalytic activity of the PtRu/C catalyst are very sensitive to the pH value of reducing solution, and the PtRu/C catalyst prepared at the pH value of 8 exhibits the better performance for methanol electrooxidation than the other samples. The size of the nanoparticles decreases as the pH value increases from 0.2 to 10 with the largest size of 4.4 nm and the smallest one of 2.1 nm. The two metal elements distribute uniformly in the catalyst and their metal loadings are similar to the theoretical value.

Rational syntheses of core–shell Fe@(PtRu) nanoparticle electrocatalysts for the methanol oxidation reaction with complete suppression of CO-poisoning and highly enhanced activity

“…In the bifunctional mechanism, CO molecules adsorbed on Pt can be removed by the following reactions. 6,[15][16][17][18][19] Ru + H 2 O → Ru-OH + H + CO ads (on Pt) + Ru-OH → CO 2 (g) + Ru + H + In the ligand effect, the electronic interaction with more electropositive Ru lowers the Pt d-band center, through which the CO-binding energy on Pt is reduced. In both cases, the surface coverage by poisoning CO is decreased, effectively increasing the catalytic activity of Pt.…”

Ultrathin graphitic carbon nitride nanosheets and graphene composite material as high-performance PtRu catalyst support for methanol electro-oxidation

“…Comparing with the XRD pattern of PtRu/C catalyst in our previous work [36], the intensities of Pt (2 0 0), (2 2 0) and (3 1 1) This could be attributed to their smaller sizes of PtRu NPs calculated from the Debye-Scherrer formula [42]. Therein, no recognizable diffractions of metallic Ru and/or Ru oxides are consisted with our precious work [43], implying that the Ru may slightly enter Pt fcc lattice to form PtRu alloy [44]. Moreover, it is reasonable to confirm that the Ru mostly exists as amorphous metallic state Ru and/or an amount of hydrous ruthenium oxides in the catalyst, but they are not clearly detected by XRD.…”

Graphitic carbon nitride nanosheet coated carbon black as a high-performance PtRu catalyst support material for methanol electrooxidation

“…39 Therein, no recognisable diffractions of metallic Ru and/or Ru oxides are consistent with our previous work. 40 As shown in Fig. 2, the Pt (111) peak of the PtRu nanoparticles at 39.8 slightly shied to higher 2q which corresponds to a decrease in the lattice constant compared to that of pure platinum at 39.6 , implying that the Ru may slightly enter the Pt fcc lattice to form PtRu alloys.…”