Cyanide-modified Pt(111): Structure, stability and hydrogen adsorption

Abstract

Cyanide-modified Pt(111) surfaces have been recently used to study atomic-ensemble effects in electrocatalysis. These studies have been based on the assumption that cyanide acts as a third body, blocking some surface sites but leaving the electronic properties of the surrounding ones unaltered, although this is in apparent contradiction with the observation of a positive shift of 0.2 V in the onset of hydrogen adsorption on cyanide-modified Pt(111) electrodes, as compared with clean Pt(111). We have performed theoretical calculations in order to provide support to this assumption and explain the positive shift in the onset of hydrogen adsorption, which is shown to be due to the formation of CNH ad .

Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers: Origin and Effect of Noncovalent Interactions

“…For the sake of comparison a line with a slope of -0.059 V, corresponding to the Nernstian behaviour expected for a PCET has also been included (dashed line). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Metal cations in the electrolyte can interact with the nitrogen atoms of CN ad , thus blocking the sites where the PCET occurs, 6,20 and increasing the concentration of alkali-metal cations above a cation-dependent threshold concentration provokes a negative shift of the onset of hydrogen adsorption on cyanide-modified Pt(111) electrodes. 6 However, in the experiments reported in Fig.…”

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“…[37] Additionally, the "ensemble effect" can be employed to drive a specific reaction, as usually demonstrated the group of Cuesta. [38] During the following two sections, we will review the most important works following both electrochemical and chemical methods for the synthesis of shaped NPs to be used as catalysts for the EOR.…”

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