Preparation And Electrochemical Sensing Properties Of Cerium Phosphate-based Nanomaterials

The concentration of some small molecules is related to many diseases,such as dopamine(DA)and uric acid(UA).Overdose of some drugs may accumulate in the body,resulting in irreversible damage to body organs.For example,overdose of acetaminophen(APAP)may lead to liver and kidney failure,and overuse of metronidazole(MNZ)may lead to cancer.Therefore,it is necessary to detect these small molecules accurately and quickly.Electrochemical method is widely used because of its high sensitivity,simple operation and short response time.CePO4 based nanomaterials have attracted extensive attention because of their good luminescence properties.Based on its unique electronic structure,CePO4 has the potential to be used in electrochemical detection.Based on this,CePO4 with different morphologies was designed and synthesized in this paper to explore its application in the field of electrochemical sensing.The main contents are as follows:1.A flower-like CePO4(F-CePO4)with hierarchical structure was hydrothermally prepared.The comparative experiments show that the amount of hydrazine hydrate and urea as well as the reaction time significantly affect the formation of nanoflowers.Due to its large specific surface area and high electron transfer efficiency,F-CePO4 was utilized for the selective detection of DA,UA and APAP with wide linear ranges,low detection limits,high stability and good repeatability.Fascinatingly,when DA,UA and APAP were detected simultaneously,the high sensitivity of F-CePO4 can be maintained.Further studies show that the different electrostatic and hydrogen-bonding interactions between the detected substrates and F-CePO4 lead to different shifts of their oxidative peak potential,which improves the recognition ability of DA,UA and APAP.In addition,the modified electrode was applied to the detection of real samples,providing a simple strategy for constructing new electrochemical detection materials.2.Ce-MOF was used as precursor to synthesize uniform rod-like,spherical and platelike CePO4 by hydrothermal method.The morphology and size of CePO4 are consistent with Ce-MOF.And CePO4 also has high purity and good crystallinity.Among them,the spherical CePO4(S-CePO4)synthesized with Ce-MOF-808 has a larger specific surface area.In addition,the study also shows that the amount of Na OH has an effect on the morphology and structure of CePO4.The glassy carbon electrode modified by S-CePO4(S-CePO4@GCE)shows better electrochemical activity,which may be due to the higher specific surface area and mesoporous structure of spherical CePO4.When S-CePO4@GCE was used to detect metronidazole,the detection limit(signal-to-noise ratio of 3)was 3.6 μM,and the linear range was 5.0-3980 μM.Not only that,the modified electrode also has good stability,reproducibility and selectivity.Finally,the constructed electrode has also been successfully applied to the detection of MNZ content in tablets and various water bodies.3.Cerium phosphate/reduced graphene oxide(CePO4-rGO)composites was synthesized by one-pot hydrothermal method.Structural analyses revealed that flaky CePO4 and few-layer rGO were composited homogeneously.It is found that the loading of rGO can greatly enhance the electrical conductivity and the adsorption capacity of the composite,leading to increased peak current and reduced oxidative potentials of DA and APAP.With these advantages,the constructed composites were developed as electrode materials for the detection of DA and APAP.Further studies showed that the loading amount of rGO and the p H value of electrolyte were also important.When DA and APAP were individually detected with CePO4-0.6rGO modified electrode,wide linear ranges of 1.2-50 μM for DA and 0.5-30 μM for APAP can be obtained,respectively.The detection limits of DA and APAP were determined to be 0.013 μM and 0.025 μM with high sensitivities of 25.58 μA·μM-1·cm-2 and 13.30 μA·μM-1·cm-2,respectively.In the process of simultaneous detection of DA and APAP,the modified electrode not only successfully separated the two peaks from DA and APAP,but also had a lower detection limit and higher sensitivity.Moreover,the modified electrode has high selectivity,good stability and satisfactory repeatability.In addition,the modified electrode was also successfully applied to detect DA and APAP in real urine samples.This paper has 44 pictures,8 tables and 140 references.