Functionally Imprinted Orthorhombic WO<sub>3</sub>·H<sub>2</sub>O Nanoplates for Ultrasensitive Photoelectrochemical Sensing with Excellent Selectivity
Yaming Xu, Neng Qin, Zhaosu Liu, Hui Han, Si Yin Tee, Guijian Guan, Ming‐Yong Han
Abstract
The current practice in molecular imprinting requires additional functional groups to be introduced into imprinted cavities of low or noncrystalline organic and inorganic matrices through covalent and noncovalent interactions with target molecules. In this research, molecular imprinting is further achieved in a highly crystalline inorganic matrix (WO3·H2O) for the first time without the need of introducing additional functional groups. Target molecules, 2,4-dichlorophenoxyacetic acid (2,4-D) have been molecularly imprinted with much stronger binding affinities to the orthorhombic WO3·H2O matrix compared to common covalent bindings such as C–C, C–H, and N–H. Also, target molecules have strong multiple interactions in the crystalline matrix so as to firmly interact with the matrix for embedding partially/completely. The effective removal of targets at an optimal temperature of 400 °C can ensure the integrity of imprinted sites of WO3·H2O nanoplates, which is important for acquiring excellent performance in ultrasensitive photoelectrochemical sensing compared to those treated at lower or higher temperatures. More targets of interest were molecularly imprinted and tested to demonstrate their excellent sensitivity/selectivity. This general photoelectrochemical platform simplifies the preparation of molecularly imprinted systems and lays the foundation for imprinting organics in visible light-responsive inorganic matrices, which is more feasible for further deviceization and miniaturization in various sensing applications such as environmental monitoring/treatment.