The Electrochemical Development of Pt(111) Stepped Surfaces and Its Influence on Methanol Electrooxidation

Abstract

The progress in the preparation of new electrode surfaces by electrochemical treatments exhibiting high faradaic efficiencies towards industrial electrocatalytic processes has gained more attention in today's scientific community. Most of the papers report new catalysts dispersed on different substrates, but some fundamental studies required for electrochemical and physical characterizations are sometimes forgotten. In this paper, we make a full staging of two electrochemical treatments that can be conducted to enhance the electrocatalytic activity of platinum surfaces, such as, electrofacetting through square wave potential programs and constant cathodic polarizations in the net hydrogen evolution region. The cathodic treatment applied at −2 V clearly develops (111) stepped planes similarly to the electrofacetting performed after applying the square wave program between 1.40 V and 0.70 V at 2.5 kHz. The X-ray diffraction patterns of both surfaces as well as on other electrofacetted platinum electrodes are obtained for comparison purposes. Moreover, the electrocatalytic activity towards methanol electrooxidation also exhibits equivalent coulombic efficiencies and 200% higher than on polycrystalline platinum as demonstrated by linear sweep voltammetry and potentiostatic current decays.

Anisotropic etching of platinum electrodes at the onset of cathodic corrosion

“…The significance of the changes caused by cathodic corrosion is emphasized by comparing them to modifications caused by repeatedly cycling at predominantly anodic potentials 35 36 37 . These latter cycling procedures can modify electrode surfaces by repeatedly oxidizing and reducing platinum in experiments that typically last 5 –10 min.…”

Evidence for Independent Glycerol Electrooxidation Behavior on Different Ordered Domains of Polycrystalline Platinum

“…The different ratios illustrate the fact that surface structure plays a key role in several electrocatalytic reactions. [13][14][15] Gomes et al showed that GEOR is sensitive to the orientation of Pt atoms at the surface by using single-crystal surfaces. [4] To understand how these superficial changes can affect the GEOR, we performed a voltammetric study in the presence of 0.2 m glycerol in the supporting electrolyte.…”

A simple synthesis method for nano-metal catalyst supported on mesoporous carbon: the solution plasma process

“…For Pt NPs, the intensity ratio between the 200 and 111 diffractions was 0.75, which was larger than the conventional bulk intensity ratio of 0.53 [JCPDS 87-0647]. 50 This indicated that the synthesized Pt NPs, which were primarily bound by 100 planes, are inclined to preferentially orient parallel to the supporting substrates. Pt 110 was found to be the most effective catalyst for the ORR in sulfuric acid electrolytes.…”