High electrocatalytic performance inspired by crystalline/amorphous interface in PtPb nanoplate

Abstract

Nanoscale PtPb catalysts with core-shell structure have been actively explored in recent years owing to their outstanding catalytic activity. We report on a new class of PtPb nanoplate (NP) catalyst with a novel structure realized by ion irradiation modification, which contains an interface formed by a crystalline phase and an amorphous phase simultaneously in an annular state. Significantly, the PtPb NP with the new structure shows superior catalytic activity towards the methanol oxidation reaction (MOR). The specific activity of PtPb NPs with the new structure reaches 4.32 mA cm-2 towards the MOR and the mass activity reaches 1.31 A mg-1, which is 1.9-fold and 1.4-fold greater than those for the original crystalline PtPb NPs, respectively. The outstanding catalytic activity could be attributed to the presence of the interface between a crystalline phase and an amorphous phase with a special electronic structure created by ion irradiation. Density functional theory calculations reveal that the novel interface activates the C-H and O-H bonds, leading to high electrocatalytic activity, and optimizes the adsorption of hydroxyl and intermediates on the surface to facilitate the oxidation reaction. The novel structure with an interface formed by a crystalline phase and an amorphous phase opens up a new approach to improve electrocatalytic activity.

Perforated Pd Nanosheets with Crystalline/Amorphous Heterostructures as a Highly Active Robust Catalyst toward Formic Acid Oxidation

“…Second, in comparison to both commercial Pd/C and Pd black, the more negative onset potentials of FAO (Figure c) and adsorbed OH ad (Figure S7, Supporting Information) for P‐Pd nanosheets might be related to the interfaces between amorphous and crystalline regions, which activate the CH and OH bonds and enhance the adsorption energy of OH ad to oxidize CO‐like intermediates, resulting in fast electrode kinetics for FAO. The property of the interfaces can also be found in previously reported literature according to the density functional theory calculations . Finally, their crosslinked nanosheet structure and rich perforations could contribute to reduce R ct for electron transport and fast mass transfer, respectively, which are consist with the analysis of AC impedances in Figure e.…”

Synthesis of Palladium‐Based Crystalline@Amorphous Core–Shell Nanoplates for Highly Efficient Ethanol Oxidation

“…In addition, these materials are either heteromaterials, in which the crystalline and amorphous areas are made of different chemical compositions, such as CuS (crystalline)/Pd‐Cu‐S (amorphous) [ 12,13 ] and Co (crystalline)/Co 3 O 4 (amorphous), [ 14 ] or homomaterials with the random distribution of the crystalline and amorphous areas, such as PtPb, [ 15 ] Pd, [ 11 ] and PdCu. [ 10 ] Furthermore, additional post‐treatment processes, such as ion irradiation treatment of the presynthesized crystalline nanoplates, [ 15,16 ] were required to obtain some of the heterostructures. Therefore, it still remains a great challenge to construct well‐defined core–shell crystalline@amorphous heterostructured nanomaterials with the same chemical components.…”

“…First, the coexistence of crystalline and amorphous structures in c ‐Pd‐Ni‐P@ a ‐Pd‐Ni‐P nanoplates benefits the formation of low‐coordination atoms, giving rise to the change of electron band structure of the Pd atoms and the enhancement in electrocatalytic activity. [ 15,16,30 ] Second, it has been demonstrated that the incorporation of oxophilic metal, such as Ni, into the Pd‐based catalysts could benefit the generation of *OH and thus enhance the catalytic activity in EOR. [ 20 ] During the EOR process, the Pd atoms generally promote the dehydrogenation of ethanol to form *CH 3 CO, which can combine with the *OH formed on Ni atoms to generate CH 3 COOH that further becomes CH 3 COO − after the reaction with OH − in the alkaline electrolyte.…”

Tuning Surface Structure of Pd3Pb/PtnPb Nanocrystals for Boosting the Methanol Oxidation Reaction

“…Such oxygenated species can promote the further oxidation of CO ads , and then remove them from Pt sites, which substantially enhance the catalytic properties of these three Pd 3 Pb/Pt n Pb nanocubes toward MOR. As such, the adsorption energy of CO on Pt‐based electrocatalysts is a critical descriptor of the intrinsic activity for MOR . In order to deeply understand the difference in MOR activity of three Pd 3 Pb/Pt n Pb nanocubes, the adsorption energies of CO on fcc‐structured Pt(111), fcc‐structured Pt x Pb(111), and hexagonal‐structured PtPb(0001) were obtained by the density functional theory (DFT) calculations.…”