Compressive Strain in Core–Shell Au–Pd Nanoparticles Introduced by Lateral Confinement of Deformation Twinnings to Enhance the Oxidation Reduction Reaction Performance

Abstract

In this work, quasi-spherical, uniform gold nanoparticles with rich deformation twinning (Audt NPs) were first synthesized with the assistance of copper­(II) ions. Then, these Audt NPs were used as the cores for the fabrication of core–shell (CS) Audt–Pd NPs with ultrathin Pd layers, which also can bear compressive strain because of the formation of corrugated structured Pd shells led by the lateral confinement imposed by deformation twinning in the Au cores. The presence of compressive strain in the CS Audt–Pd NPs can result in the widening of the d-band width of the Pd shell and further the downshift of their d-band center, which can then improve the desorption ability of intermediates and still maintain the adsorption ability of the reactants because of the broad adsorption potential range. Taking the oxidation reduction reaction and the ethanol oxidation reaction as examples, the as-prepared Audt–Pd NPs indeed exhibited superior catalytic performances because of the synergism of compressive strain and the electronic effect. Thus, our work opens a new way to introduce compressive strain in the Pd-based CS NP catalysts, which can achieve the enhancement in the electrocatalytic performance by combining the merit of compressive strain and the electronic effect.

Realization of the dehydrogenation pathway of formic acid oxidation by ultra-small core–shell Au–Pt nanoparticles with discrete Pt shells

“…4). 10 The results further indicate that the Pt atoms on the surface of the USCS D Au 61.2 @Au 27.3 Pt 11.5 NPs are not continuous and have a weak adsorption ability for CO, which is consistent with those reported in literature. 26 However, the large potential range of the CO-stripping peak of USCS D Au 61.2 @Au 27.3 Pt 11.5 -NP/C catalysts would offset the decreasing adsorption ability for CO due to the increasing amount of adsorption sites, which is indicated by the presence of the broad adsorption potential range for CO (from -0.1 to 1.05 V).…”

“…26 However, the large potential range of the CO-stripping peak of USCS D Au 61.2 @Au 27.3 Pt 11.5 -NP/C catalysts would offset the decreasing adsorption ability for CO due to the increasing amount of adsorption sites, which is indicated by the presence of the broad adsorption potential range for CO (from -0.1 to 1.05 V). 10,27 That is, USCS D Au 61.2 @Au 27.3 Pt 11.5 -NP/C catalysts would promote the desorption of intermediate products in the catalytic process towards FAOR due to the the decreasing adsorption ability, make them convert to the direct pathway, thereby enhancing the FAOR catalytic performance. According to the method reported in our previous work, 4,[28][29][30][31] the total composition and surface composition of the USCS D Au-Pt NPs also can be determined by cyclic voltammetry in alkaline medium.…”

“…CO stripping voltammetry of commercial Pt/C catalysts, USCS Au 38:4 @Au 9:3 Pt 52:3 -NP/C catalysts and USCS D Au 61:2 @Au 27:3 Pt 11:5 -NP/C catalysts was further carried out to illustrate the formation of discrete Pt shells by comparison 4): 10 The results further indicate that the Pt atoms on the surface of the USCS D Au 61:2 @Au 27:3 Pt 11:5 NPs are not continuous and have a weak adsorption ability for CO, which is consistent with those reported in the literature: 26 However, the large potential range of the CO-stripping peak of USCS D Au 61:2 @Au 27:3 Pt 11:5 -NP/C catalysts would offset the decreasing adsorption ability for CO due to the increasing amount of adsorption sites, which is indicated by the presence of a broad adsorption potential range for CO (from À0:1 to 1:05 V): 10,27 That is, USCS D Au 61:2 @Au 27:3 Pt 11:5 -NP/C catalysts would promote the desorption of intermediate products in the catalytic process towards the FAOR due to the decreasing adsorption ability and make them convert to the direct pathway, thereby enhancing the FAOR catalytic performance: 7 3:3: Determination of the elemental composition of USCS D Au 61:2 @Au 27:3 Pt 11:5 NPs According to the method reported in our previous work, 4,[28][29][30][31] the bulk composition and surface composition of the USCS D Au-Pt NPs can also be determined by cyclic voltammetry in alkaline media: The surface composition of the as-prepared USCS D Au-Pt NPs can be calculated on the basis of the surface areas of Au and Pt obtained, which can be deduced as follows:…”

“…Accordingly, they have strong adsorption to the CO species, which are the main intermediates produced from the indirect pathways (dehydration of formic acid) in FAOR, thus leading to which the loss of active sites on the surfaces. [5][6][7][8][9][10] Meanwhile, it is known that Au has good anti-poison ability to CO. [11][12][13] Therefore, continuous Pt atoms on the outersurfaces are well dispersed by a high fraction of Au atoms, which would bear an improved anti-poison ability to CO due to the decreasing density of Pt atoms and the presence of Au atoms. [14][15][16][17] In addition, the formation of atomically dispersed Pt atoms on the outer-surfaces of Au-Pt NPs would promote direct pathways (dehydrogenation of formic acid), and thus improving the catalytic performance towards FAOR.…”

Unravelling charge-transfer in Pd to pyrrolic-N bond for superior electrocatalytic performance

“…16,1718 Besides, the lattice strain invoked by smaller sizes of the alloying atoms also helps in attenuating the intermediate binding energies. 7,8,19,20 Very recently, Bi was shown to form alloy NCs with Pd, exhibiting a very high ORR E 1/2 = 0.92 V vs. RHE due to the weakening of the surface Pd-O bonds. 9 However, the activity loss was >40% after 10000 cycles.…”