SERS Resolving of the Significance of Acetate on the Enhanced Catalytic Activity of Nanozymes
Qingnan Zhao, Hai Wang, Wenji Jiang, Huimin Gao, Sisi Wen, Xin Feng, Qiong Wu, Chengyan He, You‐Liang Zhu, Lianghai Hu, Bing Zhao, Wei Song
Abstract
Understanding the structure–activity correlation and reaction mechanism of the catalytic process in an acetic acid–sodium acetate (HAc-NaAc) buffer environment is crucial for the design of efficient nanozymes. Here, we first reported a lattice restructuration of Au-LaNiO3−δ nanofibers (NFs) after acidification with the HAc-NaAc buffer to show a significantly enhanced oxidase-like property. Surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) calculation confirm the direct evidence for the formation of specific enhanced intermediate O–O species after acidification, indicating that the insertion of the carboxyl group in the A-Au/LaNiO3−δ NFs plays crucial roles in both producing vacancies in HAc-NaAc solution from its dissociation during the catalytic process and the protection of the vacancies, which can be directly interacted with oxygen in the environment to produce O–O species, realizing the enhanced oxidation of substrate molecules. The insertion of the carboxyl group increased the oxidase-like catalytic activity by 2.38 times and the SERS activity by 5.27 times. This strategy offers a way to construct an efficient nanozyme-linked immunosorbent assay system for the diagnosis of cancer through the highly sensitive SERS identification of exosomes.