Defect-Rich CoFe-Layered Double Hydroxides as Superior Peroxidase-like Nanozymes for the Detection of Ascorbic Acid
Yiping Ning, Yi Sun, Yang Xiang, Yaping Li, Aijuan Han, Bingqing Wang, Junfeng Liu
Abstract
The development of artificial enzymes with superior catalytic properties to natural enzymes has been a long-standing goal of chemists. Herein, defect-rich CoFe-layered double hydroxides (d-CoFe-LDHs) nanosheets are developed and used as superior peroxidase-like nanozymes for the detection of ascorbic acid (AA). The d-CoFe-LDHs with an average thickness of ∼3 nm and a lateral size of ∼20 nm are synthesized through rapid nucleation in a colloid mill, which exhibited abundant unsaturated sites (oxygen vacancies and cobalt vacancies). Impressively, d-CoFe-LDHs exhibited excellent peroxidase-mimicking performance with strong substrate affinity and robustness in a wide pH range. Density functional theory calculations show that d-CoFe-LDHs have lower H 2 O 2 adsorption energy, which promotes the decomposition of H 2 O 2, thereby improving the catalytic activity. The chromogenic system of d-CoFe-LDHs and 3,3′,5,5′-tetramethylbenzidine can be used to accurately detect the content of AA, and the detection limit is about 3.6 μM. This study opens up a new approach for the construction of highly active defective LDH peroxidases for the detection of biomolecules.