Palladium hydride with high-index facets for enhanced methanol oxidation

High-Energy Facet Engineering for Electrocatalytic Applications

The design of high-energy facets in electrocatalysts has attracted significant attention due to their potential to enhance electrocatalytic activity. In this review, the significance of high-energy facets in various electrochemical reactions are highlighted, including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), nitrogen reduction reaction (NRR), and carbon dioxide reduction reaction (CRR). Their importance in various electrochemical reactions and present strategies for constructing high-energy facets are discussed, including alloying, heterostructure formation, selective etching, capping agents, and coupling with substrates. These strategies enable control over crystallographic orientation and surface morphology, fine-tuning electrocatalytic properties. This study also addresses future directions and challenges, emphasizing the need to better understand fundamental mechanisms. Overall, high-energy facets offer exciting opportunities for advancing electrocatalysis.

Lattice engineering of noble metal-based nanomaterials via metal-nonmetal interactions for catalytic applications

Noble metal-based nanomaterials possess outstanding catalytic properties in various chemical reactions. However, the increasing cost of noble metals severely hinders their large-scale applications. A cost-effective strategy is incorporating noble metals with light nonmetal elements (e.g., H, B, C, N, P and S) to form noble metal-based nanocompounds, which can not only reduce the noble metal content, but also promote their catalytic performances by tuning their crystal lattices and introducing additional active sites. In this review, we present a concise overview of the recent advancements in the preparation and application of various kinds of noble metal-light nonmetal binary nanocompounds. Besides introducing synthetic strategies, we focus on the effects of introducing light nonmetal elements on the lattice structures of noble metals and highlight notable progress in the lattice strain engineering of representative core-shell nanostructures derived from these nanocompounds. In the meantime, the catalytic applications of the light element-incorporated noble metal-based nanomaterials are discussed. Finally, we discuss current challenges and future perspectives in the development of noble metal-nonmetal based nanomaterials.

Bismuth Incorporation in Palladium Hydride for the Electrocatalytic Ethanol Oxidation with Enhanced CO Tolerance

Introducing nonmetal and oxophilic metal into palladium (Pd)-based catalysts is beneficial for boosting electrocatalysis, especially regarding the improvement of mass activity (MA) and CO tolerance. Herein, the stable bismuth-doped palladium hydride (Bi/PdH) networks have been successfully fabricated through a simple one-step method. The intercalation of interstitial H atoms expands the lattice of Pd, and the doping of oxophilic metal Bi restrains the adsorption of poisonous intermediates on the surface of Pd, thereby improving the activity and durability of the as-prepared catalysts in the ethanol oxidation reaction (EOR). The obtained Bi/PdH networks manifest a remarkable MA of 8.51 A·mgPd-1, which is 11.18 times higher than that of commercial Pd/C (0.76 A·mgPd-1). The CO-stripping analysis results indicate that Bi doping can significantly prohibit CO adsorption on the surface of the Bi/PdH networks. The density functional theory (DFT) calculations also reveal that Bi doping enhances the OH* adsorption on the catalyst surface and mitigates the interaction between Pd and CO* intermediates, providing deeper insights into the origin of the enhanced EOR activity and CO tolerance. This work describes an impactful path for producing high-performance and durable PdH-based nanocatalysts.

Low Pt-Doped Crystalline/Amorphous Heterophase Pd12P3.2 Nanowires as Efficient Catalysts for Methanol Oxidation

Pd-based catalysts are attractive anodic electrocatalysts for direct methanol fuel cells owing to their low cost and natural abundance. However, they suffer from sluggish reaction kinetic and insufficient electroactivity in methanol oxidation reaction (MOR). In this work, we developed a facile one-pot approach to fabricate low Pt-doped Pd₁₂P_3.2 nanowires with crystalline/amorphous heterophase (termed Pt-Pd₁₂P_3.2 NWs) for MOR. The unique crystalline/amorphous heterophase structures promote the catalytic activity by the plentiful active sites at the phase boundaries and/or interfaces and the synergistic effect between different phases. Moreover, the incorporation of trace Pt into Pd lattices modifies the electronic structure and improves the electron transfer ability. Therefore, the obtained Pt-Pd₁₂P_3.2 NWs display significantly enhanced electrocatalytic performance toward MOR with the mass activity of 2.35 A mg_Pd+Pt^-1, which is 9.0, 2.9, and 2.0 times higher than those of the commercial Pd/C (0.26 A mg_Pd^-1), Pd₁₂P_3.2 NWs (0.82 A mg_Pd^-1), and commercial Pt/C (1.19 A mg_Pt^-1). The high mass activity enables the Pt-Pd₁₂P_3.2 NWs to be the promising Pd-based catalysts for MOR.