Enhanced Methanol Oxidation on Strained Pt Films

Abstract

We report a systematic investigation into the effect of strain on the electrocatalytic activity of films of Pt. We use an electroless deposition process to deposit the Pt onto sputtered Au substrates and characterize their structural and electrochemical properties. We found a direct correlation between the rate of methanol oxidation and the fractional surface coverage of methanol on the compressively strained catalyst surfaces. The fractional methanol surface coverage, Θ M , varied on the Pt surfaces with values ranging from 20.5 to 61.7%, depending on the level of compressive strain. A compressive strain of about ε = −0.110% resulted in a high fractional surface coverage of 61.7% with highest peak current density for methanol oxidation of 0.46 mA cm −2 and earliest peak potential of 0.67 V vs Ag/AgCl. As the absolute value of the compressive strain increased, the fractional surface coverage and peak current density for methanol oxidation decreased. Therefore, the adsorption of molecular methanol was controlled by the strain generated in the Pt films, resulting in higher fractional surface coverage and ultimately enhancing the rate of oxidation of methanol.

Bimodal nanoporous platinum on sacrificial nanoporous copper for catalysis of the oxygen-reduction reaction

“…Lattice straining affects the overall catalytic performance in platinum. [21,26,27] Strasser et al [21] discuss the effect of lattice strain on the activity of core-shell platinum catalysts for ORR, where the Pt-Cu nanoparticles are dealloyed partially to form nanoparticles with a platinum shell and a Pt-Cu core. A moderate reduction in lattice constant, namely, lattice contraction of the platinum is important to enhance the ORR activity of the platinum, although an excessive compressive lattice strain (approximately below −2.5%) deteriorates the ORR activity.…”

Oxygen reduction on bimodal nanoporous palladium–copper catalyst synthesized using sacrificial nanoporous copper

“…In the case of platinum, which has been examined intensively in previous studies, lattice straining affects the overall catalytic performance for ORR in platinum; [32][33][34] lattice contraction is favorable for efficient ORR catalysis on platinum. [32] However, it has been reported that both lattice contraction [35][36][37] and expansion [27] in palladium catalysts enhances the overall catalytic performance for ORR.…”

Coherent X-ray Imaging of CO-Adsorption-Induced Structural Changes in Pt Nanoparticles: Implications for Catalysis

“…It requires an in-depth structural characterization of heterogeneous catalysts, representing a material with a rather complex morphology, as they are composed of oxide-supported metal nanoparticles. The metal nanoparticle shape is directly related to the catalytic behavior since it defines the possible adsorption sites, characterized by different local geometry, and therefore the absorption energy. − Another important quantity is the nanoparticle’s internal strain field, since it alters the adsorption probability and, thus, the activity and selectivity of the adsorption sites. − Because only a fraction of strained surface atoms can alter the catalytic activity, the atomic site-specific strain determination plays an important role…”