Hollow Aluminosilicate Microspheres with Increased Surface Hydroxyl Groups by Etching Method for Electrochemical Detection of Hg(II)

Tuning the concentration of hydroxyl groups (-OH) to improve the adsorption ability of nanomaterials has attracted broad interest in the field of environmental contaminant analysis. In this work, we provide efficient directions for enhancing the detection performance of Hg(II) through controlling the etching time of SiO2 in NaAlO2 solution to modulate the concentration of surficial -OH. It is found that the hollow aluminosilicate microspheres (HAM) with an etching time of 28 min shows the best detection sensitivity of 795.33 mu A mu M-1 cm(-2) for Hg(II), compared to that of SiO2 and yolk-shell microspheres (YSM). X-ray photoelectron spectroscopy (XPS) results confirm that the HAM exhibits the highest concentration of -OH, which can bond with Hg(II) to promote its adsorption on the electrode surface and then enhance the detection signal of Hg(II). In addition, the HAM modified electrode is used to realize the electrochemical analysis of Hg(II) in real water samples and achieved satisfactory results. This study facilitates understanding the adsorption mechanism between -OH and target HMIs during the detection process and designs the nanomaterials with highly -OH concentration for electrochemical detection of HMIs.