One‐Pot Synthesis of Hat‐like PdAu Alloy Open Nanostructures with Improved Oxidase‐like Activities

Abstract Controlled assembly of two‐dimensional (2D) noble metal nanocrystals into three‐dimensional (3D) open architecture with reasonable interparticle distance is of great value to solve the re‐stacking issue for practical application, which yet achieves limited progress for bimetallic nanocrystals. Herein, we report the synthesis of hat‐like palladium‐gold (PdAu) alloy nanocrystals with the building block of nanosheet and explored their catalytic properties when serving as oxidase‐like nanoenzyme. The success of current synthesis lies on the co‐reduction of Au and Pd precursors under kinetics‐controlled condition, together with the use of glutathione molecules as the shape‐directing agent. The use of OTAC as capping agent is crucial for the unique morphology, where wire‐like and quasi‐spherical products are obtained, respectively, when the capping agent is replaced by CTAB and CTAC, respectively. Systematic investigations reveal that the oxidase‐like activities of these PdAu nanocrystals are highly morphology‐dependent. In particular, the PdAu alloy nanohats displayed the highest oxidase‐like activity, as well as a wide linear range (100–5000 μM) and low detection limit (25 μM). The present study drives the development of synthetic strategies that allows the construction of 2D bimetallic nanocrystals with a 3D open structure, and validates their improved performance as nanoenzyme towards practical sensing applications, which may find important use in the rational design of biocatalysis, bioassays, and nano‐biomedicine.