Ultrafine Core@Shell Cu<sub>1</sub>Au<sub>1</sub>@Cu<sub>1</sub>Pd<sub>3</sub> Nanodots Synergized with 3D Porous N-Doped Graphene Nanosheets as a High-Performance Multifunctional Electrocatalyst
Liuxuan Luo, Cehuang Fu, Yangge Guo, Xiyang Cai, Xiashuang Luo, Zehao Tan, Rui Xue, Xiaojing Cheng, Shuiyun Shen, Junliang Zhang
Abstract
Rationally combining designed supports and metal-based nanomaterials is effective to synergize their respective physicochemical and electrochemical properties for developing highly active and stable/durable electrocatalysts. Accordingly, in this work, sub-5 nm and monodispersed nanodots (NDs) with the special nanostructure of an ultrafine Cu 1 Au 1 core and a 2–3-atomic-layer Cu 1 Pd 3 shell are synthesized by a facile solvothermal method, which are further evenly and firmly anchored onto 3D porous N-doped graphene nanosheets (NGS) via a simple annealing (A) process. The as-obtained Cu 1 Au 1 @Cu 1 Pd 3 NDs/NGS-A exhibits exceptional electrocatalytic activity and noble-metal utilization toward the alkaline oxygen reduction, methanol oxidation, and ethanol oxidation reactions, showing dozens-fold enhancements compared with commercial Pd/C and Pt/C. Besides, it also has excellent long-term electrochemical stability and electrocatalytic durability. Advanced and comprehensive experimental and theoretical analyses unveil the synthetic mechanism of the special core@shell nanostructure and further reveal the origins of the significantly enhanced electrocatalytic performance: (1) the prominent structural properties of NGS, (2) the ultrasmall and monodispersed size as well as the highly uniform morphology of the NDs-A, (3) the special Cu–Au–Pd alloy nanostructure with an ultrafine core and a subnanometer shell, and (4) the strong metal–support interaction. This work not only develops a facile method for fabricating the special metal-based ultrafine-core@ultrathin-shell nanostructure but also proposes an effective and practical design paradigm of comprehensively and rationally considering both supports and metal-based nanomaterials for realizing high-performance multifunctional electrocatalysts, which can be further expanded to other supports and metal-based nanomaterials for other energy-conversion or environmental (electro)catalytic applications.