SnO2 doped NiO heterostructure nanofibers prepared by electrostatic spinning: A novel sensor for catalytic oxidation of formaldehyde

Here, a p-n-type SnO 2 /NiO heterojunction semiconductor electrochemical sensor was prepared via electrospinning. Structural analysis revealed that the roughness of the composite nanofibers was related to the mass ratio of SnO 2 and NiO, when the nanofibers prepared at the same mass ratio were the smoothest and had the best electrochemical properties. SnO 2 /NiO NFs exhibited better electrocatalytic oxidation capability, excellent selectivity, good stability, and a detection limit of 2.8 nM. SnO 2 /NiO NFs were excellent favorable sensing materials for the detection of Liquid formaldehyde, it could stimulate greater innovation for future sensor technologies. • An electrochemical sensor for the detection of liquid formaldehyde is proposed. • Five different ratios of electrode materials were set up to find the best ratio for detection performance. • This electrochemical sensor has a low detection limit and a wide detection range for formaldehyde detection. • The sensing mechanism of the sensor was analyzed. • The selectivity and stability of this electrochemical sensor for HCHO were analyzed. Up to now, there were a large number of literatures on the detection of gaseous formaldehyde (HCHO), however the liquid HCHO, which had the same harmfulness as gaseous HCHO, was rarely paid attention to by people. In this work, the electrospinning nanomaterial preparation process was used to fabricate the liquid HCHO electrochemical sensor. Firstly, five different sets of electrode materials were set up, and the material with the best results (SnO 2 /NiO NFs (No. 3)) was tested by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry (CV), and electrochemical frequency impedance (EIS). Then the detection principle of the electrochemical sensor and the electrode reaction process of catalytic oxidation of HCHO were analyzed. Finally, the limit of detection (LOD), detection range, selectivity, and stability of the SnO 2 /NiO NFs (No.3) for the catalytic oxidation reaction of HCHO were analyzed by CV and potential polarization methods.