Preparation And Performance Study Of Pt-based Modified Electrodes For Formaldehyde Electrochemical Sensors

As a common teratogenic and carcinogenic substance in the environment,formaldehyde has an irritating odour and strong toxicity,which threatens people’s health all the time.At present,traditional formaldehyde detection methods cannot meet the demand for rapid and accurate detection in the field.Finding an efficient electrode material for electrochemical formaldehyde sensors with fast response performance to formaldehyde is the key to the current breakthrough in formaldehyde detection technology.In this paper,Pt-based/Nafion/GCE,Pt-based/ZrO₂/GCE and Pt Pd/CZO/GCE electrochemical sensors for formaldehyde detection were prepared by drop coating,cyclic voltammetry and wet chemical methods,and the effects of Pt and Pt Pd on the catalytic oxidation performance of formaldehyde on different carriers were investigated.electrodes on the oxidation mechanism of formaldehyde,and finally the feasibility of the application of the electrodes in the formaldehyde sensor was evaluated by field experiments.The main research results are as follows:（1）Pt/Nafion/GCE and Pt Pd/Nafion/GCE were prepared,and due to the synergistic effect of Pt Pd,toxic intermediates（CO）_ads could be removed,resulting in better catalytic oxidation activity of Pt Pd/Nafion/GCE compared to Pt/N afion/GCE.When the Nafion dosage was 6μL,the optimal Pt Pd deposition number was 40 turns and the optimal C_Pt:C_Pd=1:1.After 200 s of enrichment at-0.1 V enrichment potential at a scan rate of 100 m V/s,Pt Pd/Nafion/GCE showed the best response to formaldehyde,and its formaldehyde sensor exhibited good selectivity,reproducibility and stability with a field the recoveries of the water samples were in the range of98.0%～104.8%.（2）Pt/ZrO₂/GCE and Pt Pd/ZrO₂/GCE were prepared and due to the co-catalytic effect of ZrO₂ and the synergistic effect between Pt Pd,Pt Pd/ZrO₂/GCE showed better catalytic oxidation activity towards formaldehyde.When the number of ZrO₂deposition turns was 8,the number of Pt Pd deposition turns was 40 and C_Pt:C_Pd=1:1,the Pt Pd/ZrO₂/GCE showed the best response performance for formaldehyde after enrichment at-0.1 V enrichment potential for 200 s at a scan rate of 100 m V/s.The formaldehyde sensor showed excellent selectivity,reproducibility and stability,and performed well in the detection of field water samples with the recoveries ranged from99.0%to 103.6%.（3）CZO/GCE and Pt Pd/CZO/GCE were prepared,where Pt Pd/CZO/GCE showed excellent sensitivity for formaldehyde,very low detection limits,excellent selectivity,good reproducibility and long-term stability.When C_Cu:C_Zn=1:1 and C_Pt:C_Pd=1:1,Pt Pd/CZO/GCE showed the best response performance for formaldehyde aft er 150 s of enrichment at-0.1 V enrichment potential under UV irradiation and at a scan rate of100 m V/s,with the recovery of the field water sample detection ranging from 97.7%to 103.4%.