Role of Nanomorphology and Interfacial Structure of Platinum Nanoparticles in Catalyzing the Hydrogen Oxidation Reaction

Abstract

This work studies the hydrogen oxidation reaction using both single mesoporous platinum nanoparticles (r np = 23.1 ± 2.1 nm) and low density random arrays of material. The activity of the platinum catalyst, toward the oxidation of hydrogen, is shown to be potential dependent and exhibits two peaks in activity. These peaks in activity are measured at both random arrays of platinum nanoparticles and at the single entity scale. This alteration in the particle activity is directly reflected in the variation of the electrochemical current. These peaks in current do not relate to a mass-transport limitation of the reaction, and at high overpotentials the oxidation reaction becomes fully inhibited. This potential dependency is revealed at high current densities and arises due to the sensitivity of the reaction rate to the platinum interfacial structure; the decrease in activity [at ca. −0.2 V vs Ag/AgCl (1 M KCl) in a nonbuffered condition] directly correlates with the potential at which underpotential deposited hydrogen is removed from the catalytic interface. The contribution of the internal mesoporous nanoparticle structure toward the total particle catalytic activity is further evidenced through comparison of the time-current transients recorded for individual nanoparticles of differing morphology (solid vs mesoporous) and by evidencing the sensitivity of the single particle catalytic activity to the used supporting electrolyte concentration.

Hydrogen peroxide reduction on single platinum nanoparticles

“…Comparable results have been obtained for the hydrogen oxidation reaction where the catalytic oxidation rate reached a maximum when the platinum surface was only partially covered in hydrogen. 27…”

Understanding mass transport influenced electrocatalysis at the nanoscale via numerical simulation

“…[81][82] However the temptation to include a surfeit of reactions is sometimes found to be irresistible whilst the inclusion of adsorption effects and of usually requires self-written software, although the KISSA program offers an off-the-shelf approach to the analysis of adsorption process. 83 Enhancing studies of electrocatalysis at the single-nanoparticle or even molecular levels will require stochastic simulations, where higher-performing parallel computation (such as the application of Graphics Processing Units), 84 the consideration of possible effects of potentiostat hardware (such as the filter), 85 and the case-bycase data processing procedure designed according to the real experimental environment 86 are often emphasized in self-written programs.…”

Nanoparticle‐ and Nanotube‐Modified Electrodes: Response of Drop‐Cast Surfaces

“…The 30 nm Pt nanoparticles have been previously characterized by HR‐CTEM [18] and shown to be an aggregate of much smaller nanoparticles of approximate diameter 3 nm (Figure 2a) [18] . Such morphology is typical of Pt nanoparticles grown in the solution phase [18–19] and is potentially advantageous in the determination of arsenic because of their high active surface area [18–20] …”