Preparation And Application Of Hollow Nanomaterials In Chemical Sensing

Hollow nanomaterials have the advantages of high specific surface area,low density,micro-reactor environment,higher load capacity,and shortened mass-to-charge transfer length.In this paper,a series of hollow porous nanomaterials were synthesized by the hydrothermal method,template method,and etching method.The morphology and size of the hollow nanomaterials were characterized.A series of ECL and electrochemical sensors were constructed through signal amplification strategies.These sensors include dual-signal ECL sensors,dual-mode electrochemical sensors,etc.,which realized the applications of hollow nanomaterials in chemical sensing.1.Hollow Fe/Co-MOF was synthesized by using polystyrene microspheres as hard templates.The ECL aptasensor was constructed with hollow Fe/Co-MOF-loaded silver nanoparticles to determine chlorpyrifos.Hollow Fe/Co-MOF can catalyze the luminol-hydrogen peroxide system to produce more O₂^·-to improve the luminol efficiency.At the same time,silver nanoparticles can enhance luminol-hydrogen peroxide luminescence.The ECL signal was double-amplified by hollow Fe/Co-MOF and silver nanoparticles.The detection range of the constructed ECL aptasensor was 0.01 pM?0.1?M,and the detection limit was 0.042 pM.2.The hollow copper-cobalt-MOF material was synthesized by the soft template method,and the sheet-like C₃N₄ was synthesized by the ultrasonic method.The hollow copper-cobalt-MOF was loaded with luminol and acetamiprid aptamer,and the sheet-shaped C₃N₄ was loaded with malathion aptamer.An ECL aptasensor for simultaneous detection of acetamiprid and malathion was constructed.The linear range of acetamiprid and malathion was 0.1 pM?0.1?M,and the detection limits were 0.015 pM and 0.018 pM(S/N=3),respectively.This work provides a new idea for the simultaneous detection of multi-component pesticides.3.Hollow porous Fe₂O₃ was synthesized by high-temperature oxidation of Prussian blue.Fe₂O₃ can catalyze the reduction of hydrogen peroxide to generate current signals.Methylene blue can intercalate double-stranded DNA to generate redox signals.Square Wave Voltammetry(SWV)and i-t dual-mode electrochemical aptasensors were constructed.The detection range of SWV mode was 0.1 pM?1?M,and the detection limit was 0.034 pM(S/N=3);the detection range of the i-t method was 0.1?M?1 n M,and the detection limit was0.38 n M.Two output signals are mutually verified to increases the accuracy of detecting acetamiprid.This sensor provides a new idea for the detection of acetamiprid.4.Hollow silicon dioxide was synthesized by the etching method.Since hollow silica has a large specific surface area and a shortened mass-to-charge transfer length,it is more suitable for loading aptamers than solid silica.Taking the current generated by DNA itself as the sensing strategy,an electrochemical aptasensor for chlorpyrifos was constructed.The detection range was 0.1 pM?0.1?M,and the detection limit was 0.028 pM.It provides new ideas for the detection of chlorpyrifos.