The rational design and synthesis of two-dimensional (2D) materials with specific composition, morphology, and surface atomic structure is of great importance for the practical applications in electrocatalysis. Herein, we report a facile synthesis of channel-rich ultrathin palladium-silver nanosheets (PdAg NSs) by a simple wet-chemical strategy based on the self-assembly of docosyltrimethylammonium chloride (C₂₂TAC). The nanosheets consist of 2D ultrathin nanosheets with many accessible channels and alloyed crystalline feature. The formation mechanism of PdAg NSs is systematically investigated via a series of control experiments, including reaction time, surfactant, Pd/Ag molar ratio, temperature, and reducing agent. It is demonstrated that C₂₂TAC molecule with long alkyl chain and interplay between constituent metals is crucial for the anisotropic growth of 2D nanosheets. Such C₂₂TAC-based synthetic strategy can also be extended to the synthesis of PdAg nanowires (PdAg NWs) and Pd mesoporous nanobowls (Pd NBs). Benefit from composition and structure advantages, the obtained PdAg NSs exhibit superior electrocatalytic performance toward formic acid oxidation reaction (FAOR) with mass activity of 987 mA mg⁻¹ and specific activity of 50.1 A m⁻² at 0.3 V, which are better than those of PdAg NWs and Pd NBs, even surpass commercial Pd black. We believe the synthetic strategy outlined here would open a new avenue for engineering of noble-metal nanocrystals for a broad range of applications.

具有特定组成，形态和表面原子结构的二维（2D）材料的合理设计和合成对于电催化的实际应用非常重要。在这里，我们报告了一种基于通道基三甲基氯化铵自组装（C ₂₂ TAC）的简单湿化学策略，可轻松合成富通道的超薄钯银纳米片（PdAg NSs ）。纳米片由具有许多可及通道和合金化晶体特征的二维超薄纳米片组成。通过一系列控制实验系统地研究了PdAg NSs的形成机理，包括反应时间，表面活性剂，Pd / Ag摩尔比，温度和还原剂。证明C ₂₂具有长烷基链和构成金属之间相互作用的TAC分子对于2D纳米片的各向异性生长至关重要。这种基于C ₂₂ TAC的合成策略也可以扩展到PdAg纳米线（PdAg NWs）和Pd介孔纳米碗（Pd NBs）的合成。得益于组成和结构上的优势，所获得的PdAg NSs对甲酸氧化反应（FAOR）表现出优异的电催化性能， 在0.3 V时的质量活度为987 mA mg ^-1，比活度为50.1 A m ^-2，优于PdAg NW和Pd NB的数量甚至超过了商用Pd黑色。我们认为，本文概述的合成策略将为广泛应用的贵金属纳米晶体的工程开发开辟新途径。