Seedless and Surfactant-Free Synthesis of Polyhedron Gold Nanocrystals Enclosed by High-Index Facets for Enhanced Electrochemical Detection of Benzoyl Peroxide in Flour.

Polyhedron gold nanocrystals enclosed by high-index facets (HIF-Au NCs) are in high demand but are very difficult to prepare. To address this issue, we presented a simple, seedless method for synthesizing uniform HIF-Au NCs in an aqueous solution, which remarkably reduced the synthesis difficulty. Interestingly, the protonated NH which served as both the reducing and capping agent played a crucial role in modulating the kinetic growth of the HIF-Au NCs. The resulting HIF-Au NCs exhibited distinct electronic oxidation inertness toward alcohol but demonstrated exceptional activity in the electrocatalytic oxidation of peroxides. To demonstrate their sensing capabilities, an electrode decorated with HIF-Au NCs was used to selectively detect benzoyl peroxide (BPO) in flour. BPO is a prohibited whitening agent that may be illegally added to flour and other products, posing potential health risks. The results demonstrate that this assay offers a promising method for the sensitive and selective detection of BPO. In conclusion, this research provides a straightforward pathway for obtaining HIF-Au NCs and further demonstrates their use in electronic sensing. It is expected that HIF-Au NCs will serve as a powerful tool in plasmon-enhanced spectroscopies, catalysis, and sensing applications.