Composition-controlled Synthesis of PtCuNPs Shells on Copper Nanowires as Electrocatalysts

Boosting alkaline hydrogen evolution performance with alkaline electro-activated ultrafine candied haws-shaped PtWNi nanoalloys

Hydrogen is a promising substitute for non-renewable fossil fuels. Producing hydrogen fuel by electrolyzing water is an effective strategy to address the growing environmental problems. Platinum (Pt) is still the most active electrocatalyst to catalyze the hydrogen evolution reaction (HER) in alkaline media. Herein, we demonstrate that ultrafine candied haws-shaped PtWNi nanoalloys modified with the Ni species (Niⁿ⁺) could be formed in the alkaline electroactivation process of PtWNi alloys. Notably, the Ni species (Niⁿ⁺) promoted the decomposition of water and produced hydrogen intermediates, which were then immediately adsorbed on the surface of Pt and recombined into molecular hydrogen. Moreover, these hydrogen intermediates also enhanced the instability of the HO-H bond, leading to an increase in the total activity.

Low Pt-Content Ternary PtNiCu Nanoparticles with Hollow Interiors and Accessible Surfaces as Enhanced Multifunctional Electrocatalysts

Developing highly active and durable electrocatalysts with low levels of Pt content toward some crucial reactions including oxygen reduction reaction, hydrogen evolution reaction, and methanol oxidation reaction in an acidic electrolyte environment are desirable but still an open challenge for clean and efficient energy conversion. Herein, we present a facile route to synthesize low Pt-content ternary PtNiCu nanostructures with hollow interior and accessible surfaces (H-PtNiCu-AAT NPs) as enhanced multifunctional electrocatalysts. The galvanic replacement reaction and atomic diffusion between in situ preformed CuNi nanocrystals and Pt species should be responsible for the formation of hollow PtNiCu NPs. Continuous activation by acid picking and annealing treatments were performed to leach out the excessive Cu and Ni on the surfaces and to enrich Pt-content on the surface. H-PtNiCu-AAT NPs exhibit excellent activity and durability toward HER, ORR, and MOR due to the rational integration of multiple structural advantages. Strikingly, the mass activity and specific activity of H-PtNiCu-AAT NPs (0.977 A mg_Pt^-1 and 1.458 mA cm^-2) is 7.1 and 6.9 times higher than that of commercial Pt/C (0.138 A mg_Pt^-1 and 0.212 mA cm^-2) toward ORR at 0.9 V (vs RHE), respectively. This present work provides an efficient strategy for the design of low Pt-content trimetallic electrocatalysts with excellent activity and durability.

Facile Synthesis of Cu/NiCu Electrocatalysts Integrating Alloy, Core-Shell, and One-Dimensional Structures for Efficient Methanol Oxidation Reaction

The design and development of low-cost Pt-free, high-active, and durable noble-metal-free electrocatalysts for methanol electrooxidation is highly desirable but remains a challenge. Herein, unique Cu/NiCu nanowires (NWs) integrating alloy, core-shell, and one-dimensional structures are prepared by a facile one-pot strategy. It is found that the Ni-Cu surface alloying structure can effectively change the charge distribution of the atomic configuration, the core-shell structure can be optimized with the usage of Ni and Cu, and the one-dimensional structure can effectively enhance the charge transfer between the electrode surface and the active sites, making the prepared NWs promising electrocatalysts. Detailed catalytic investigations showed that the obtained Cu/NiCu NWs exhibit an enhanced electrocatalytic performance for methanol oxidation reaction (MOR). The optimized Cu/NiCu NWs in this work show a mass current density of 867.1 mA mg_metal^-1 at 1.55 V (vs. RHE) for MOR, which is far higher than those of Ni-based previously reported electrocatalysts. This work opens up a new pathway for the design and engineering of noble-metal-free alloy electrocatalysts with enhanced activity and durability.