Unique Activity of Platinum Adislands in the CO Electrooxidation Reaction

Abstract

The development of electrocatalytic materials of enhanced activity and efficiency through careful manipulation, at the atomic scale, of the catalyst surface structure has long been a goal of electrochemists. To accomplish this ambitious objective, it would be necessary both to obtain a thorough understanding of the relationship between the atomic-level surface structure and the catalytic properties and to develop techniques to synthesize and stabilize desired active sites. In this contribution, we present a combined experimental and theoretical study in which we demonstrate how this approach can be used to develop novel, platinum-based electrocatalysts for the CO electrooxidation reaction in CO(g)-saturated solution; the catalysts show activities superior to any pure-metal catalysts previously known. We use a broad spectrum of electrochemical surface science techniques to synthesize and rigorously characterize the catalysts, which are composed of adisland-covered platinum surfaces, and we show that highly undercoordinated atoms on the adislands themselves are responsible for the remarkable activity of these materials.

Functional links between stability and reactivity of strontium ruthenate single crystals during oxygen evolution

“…Since it is very difficult to decouple morphological and electronic effects in (electro)catalysis, it would be very difficult to unambiguously determine which of these two properties may govern the observed structure-function relationships. The importance of surface defects is well documented for metal-electrolyte interfaces 56,57 ; for example, many anomalous activities observed on singlecrystal metal surfaces in electrochemical systems were found to be predominately governed by characteristic types of surface defects. The same applies to the noble metal oxides, for example, crystalline thermal oxides are always much less active than highly defective electrochemically made oxides 54 .…”

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

“…6,7 In particular, Pt has been used as a model system to provide surface chemical and structural transformation insights under various (electro)chemical reaction environments. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Ultimately, the scope of these studies is to expedite the development of novel and cost-effective catalysts with tailored physical/chemical properties, capable of achieving, if not surpassing, the Pt electrocatalytic performance. 8,[24][25][26][27] Previous studies have been conducted to indentify the role of Pt oxides in the oxygen evolution reaction pathway (also known as oxygen discharge).…”

“…Such an increase is oen attributed to an increase of the surface oxide layer thickness and Pt dissolution. 13,[15][16][17][18][19][20][21][22][23][24][25][26]29 In alkaline media, the reversible binding of a hydroxide ion (OH À ) coupled to a one electron oxidation is thought to precede the removal of one proton and one electron to form surface oxide species. 30 This hypothesis has been mostly supported so far by surface structure and chemical characterizations far from operando conditions, 6,31,32 thereby limiting an unambiguous investigation of the role of Pt oxides in the oxygen evolution catalytic cycle.…”

Effect of the Surface Structure of Pt(100) and Pt(110) on the Oxidation of Carbon Monoxide in Alkaline Solution: an FTIR and Electrochemical Study

“…Previous studies paid special attention to the surface structure and the effect of pH [1][2][3][4][5][6][7][8][9]. Several studies have been carried out to elucidate the kinetics and mechanism of the CO oxidation on platinum electrodes in acidic media [1][2][3][4]6] as well in alkaline media [7][8][9].…”