Elastic strain effects on catalysis of a PdCuSi metallic glass thin film

Abstract

The influence of strain on catalytic activity has previously been examined directly by calculations and indirectly by experiments. The origin of the phenomenon has been attributed to strain-induced changes in the catalyst electronic structure. By employing a Pd-based metallic glass film capable of large elastic strains, we provide direct experimental evidence for catalytic activity being differently influenced by mechanically applied uniaxial tensile and compressive strains. We demonstrate the effect on the oxygen reduction reaction with cyclic voltammetry (CV) curves at different strain levels and compare X-ray photoelectron spectrometry (XPS) results for unstrained and strained (in uniaxial tension) specimens to confirm valence electron band shifts. The experimental findings are complemented by electronic structure calculations on single crystal Pd, as well as alloys with Cu and Si. The CV and XPS shifts observed in the experiments are consistent in both direction and magnitude to those predicted by theory for single crystal Pd.

Recent Advances in Metallic Glass Nanostructures: Synthesis Strategies and Electrocatalytic Applications

“…Dealloying was reported to create a core-shell catalyst with a PtCu 3 -core/Pt-rich shell. [125] Yang et al [125] reported a Pd-base MG film to address strain-induced changes in the catalyst electronic structure. Yang et al used smooth thin film electrodes and ORR was recorded by cyclic voltammetry instead of an RDE electrode.…”

“…[41] The low values in Figure 13b relative to Pt/C are mainly due to the surface structure and ORR measurement methodology. [125] Later, Yang and Kumar showed that on a 20 nm layer of a Pd 70 Zr 30 , compressive elastic strain enhances the catalytic activity of Pd and Pt during ORR, while tensile elastic strain suppresses it. [125] Yang et al [125] reported a Pd-base MG film to address strain-induced changes in the catalyst electronic structure.…”

“…Doubek et al reported an ECSA of ≈20 m 2 Ptg −1 for nanoporous nanorods, [12] Gumeci et al ≈20-30 m 2 Ptg −1 for sonochemically prepared nanoparticles, [41] Kolla and Smirnova Adv. a) Reported values of onset potential and current density for ORR in RDE experiments from references, a (PdCuSi), [125] b (Pd-NiB/C), [55] c (Ni59Nb40PtxM1-x (M = Ru, Sn)), [126] d (Pt 42.5 Cu 27 Ni 9.5 P 21 ), [12] e (PtCu 3 ), [41] f (PtIrCo/C), [57] g (AgCu). 2019, 31, 1802120 Figure 13.…”

The Influence of Elastic Strain on Catalytic Activity in the Hydrogen Evolution Reaction

“…[7] Voiry et al [8] reported chemically exfoliated WS 2 as efficient catalysts for H 2 evolution with low overpotentials and the enhanced electrocatalytic activity of WS 2 is due to the high concentration of the strained metallic octahedral phase in the asexfoliated nanosheets.S trasser et al studied PtCu@Cu core@shell system formed by de-alloying Pt-Cu nanoparticles, [9] and attributed increases in catalytic activity for oxygen reduction reaction (ORR) to the elastic strain in the dealloyed shell. [12,13] More recently,Y ang et al [14] demonstrated as imilar effect for ORR on aP d-based metallic glass catalyst film under both tensile and compressive strains,w hich have opposite effect on catalytic activity.D u et al [15] further confirmed the elastic strain on NiTis hape memory alloy in ORR, whereas the compressive strain enhanced the ORR activity and the strain can be influenced by the applied temperature.S ethuraman et al [16] subjected thin films of Pt on single-crystal Si substrates to external straining while the films were participating in ORR through cyclic voltammetry (CV). [10] Thes aturation of activity with the estimated elastic strain and the absence of the expected volcano plot were attributed to possible relaxation mechanisms in the shell.…”

“…[18] HER, which is the halfcell reaction responsible for the evolution of H 2 ,i si deally suited for studying the effect of elastic strain as it is well established that the binding energy of H-expressed as the free-energy change of hydrogen adsorption (DG H )-is the primary predictor of the effectiveness of an electrocatalyst for HER, with an ideal catalyst having DG H of about 0eV. [14,21] Hence,weshould expect compressive strain to weaken the H binding energy on metals to the left of the volcano peak, moving them towards the peak and thus enhancing their activity towards HER;tensile strain should decrease activity. Theactivity decreases to the left of volcano peak due to stronger Hbinding (DG H < 0), the activity decreases to the right of the peak as well where H binding is weaker (DG H > 0).…”