NiCoPd Inlaid NiCo-Bimetallene for Efficient Electrocatalytic Methanol Oxidation

Abstract

Pd-based metallenes have attracted great attention recently as newly burgeoning two-dimensional (2D) materials, attributed to their significantly increased active surface areas and intrinsic electrocatalytic activities. Therefore, they could be used as a potential candidate as the highperformance electrocatalyst for methanol oxidation reactions (MORs) in the direct methanol fuel cell. Herein, a new strategy is proposed to fabricate NiCoPd inlaid NiCo-bimetallene (NiCoPd/NiCo-bimetallene) by the structure directing effect of 18-crown-6 ether under an ultrasonic-pulse interface together with the HCHO reduction and atom-diffusion-aging process. NiCoPd ternary-alloys with uniformly dispersed Pd active sites are decorated onto NiCo-bimetallenes, achieving remarkably enhancing the effective utilization of Pd atoms. What is more, the intrinsic activity is enhanced by the "bifunctional mechanism" of NiCo-bimetallene adsorption of intermediate species and increased Pd-active sites. Moreover, the anti-CO poisoning ability is optimized through the "alloying ligand effect" of NiCoPd. Therefore, the NiCoPd/NiCo-bimetallene exhibits excellent mass activity for MOR, which is higher than commercial Pd/C. This work suggests a new way of the Pd-based metallenes catalyst approach to the efficient electrocatalytic MOR.

PdCu Bimetallene for Enhanced Oxygen Reduction Electrocatalysis

“…Two-dimensional (2D) nanostructures, with a large surface-to-volume ratio, high electron mobility, and sufficient active sites, have attracted more focus in catalytic fields. − Metallene, composed of bare metal atoms with atomical thickness, possesses highly curved geometrical configurations, high density of unsaturated metal atoms, and outstanding electronic conductivity, ,− which has a wide range of applications in electrocatalysis. − In order to decrease the adsorption energy of oxygen, the introduction of another metal into the Pd lattice is a promising strategy, which not only effectively modifies the electronic structure of Pd and thus optimizes ORR performance but also decreases the usage of noble metals. − It has been reported that the PdCu alloy is considered as a more promising ORR electrocatalyst because of the suitable oxygen adsorption energy . However, the anisotropic 2D ultrathin bimetallic nanostructures possess high surface free energy, which is thermodynamically favorable to aggregation. , Therefore, developing a facile method for the construction of ultrathin 2D alloy nanomaterials for fuel cells is highly desirable.…”

B-Doping-Induced Lattice Expansion of Pd Metallene Nanoribbons for Oxygen Reduction Reaction

“…19−21 As a new class of graphene-like 2D metal nanomaterials, metallene not only exposes numerous surface atoms as catalytically active centers but also has an atomically thin thickness. 22,23 For example, Wang's group successfully prepared Pd nanobeltbased materials, which were applied in an efficient electrocatalytic reaction. 24 In addition to modulating the morphological structure, lattice strain engineering and electronic structure modification of catalysts are also essential for enhancing electrocatalytic properties.…”

“…It is believed that modifying the morphological structure of Pd-based catalysts influences their catalytic performance. − Among the various structures, the two-dimensional (2D) structure possesses special electronic, photonic, and surface properties that can greatly boost its catalytic activity. − As a new class of graphene-like 2D metal nanomaterials, metallene not only exposes numerous surface atoms as catalytically active centers but also has an atomically thin thickness. , For example, Wang’s group successfully prepared Pd nanobelt-based materials, which were applied in an efficient electrocatalytic reaction . In addition to modulating the morphological structure, lattice strain engineering and electronic structure modification of catalysts are also essential for enhancing electrocatalytic properties. − Recently, the incorporation of nonmetallic elements to induce the lattice strain and tune the electronic structure of metal has become a universal and powerful strategy. − The adsorption behavior of intermediates in electrocatalytic reaction could be optimized by the induced strain effect, thus enhancing catalytic performance. , Meanwhile, it has been reported that tuning the electronic structure of metals through doping may boost its ORR activity and durability. , The intercalation strategy of B-element is one of the effective ways to give rise to lattice expansion and electronic structure modulation of the catalyst. , For instance, Liu and co-authors reported that inserting B atoms into Pd crystals could enlarge Pd–Pd interatomic spacings and contribute to the electronic effect, thereby weakening the adsorption between oxygen-containing intermediates and the Pd surface .…”

Electronic and Structural Modification of Three-Dimensional Porous NiCo@NF as a Robust Electrocatalyst for CO2 Emission-Free Methanol Upgradation to Boost Hydrogen Co-production

“…38,39 The durability of electrocatalysts is an important factor in MOR activity, and most of the reported electrocatalysts had very low durability because the CO intermediate generated during methanol oxidation blocked the active sites. 40,41 As a result, there is an urgent need to develop electrocatalysts with high durability for MOR. The majority of the reported NiCo-based electrocatalysts demonstrated complete methanol oxidation to convert methanol into CO 2 , but it is required to selectively convert methanol into a valuable formate product.…”