Search

The cataluminescence (CTL) reaction detects the presence and concentration of toxic volatile organic compounds by detecting the luminescence intensity of the different components of the gas mixture. In our study, a cataluminescence online sensor system based on LaCO 3 OH microspheres was developed for the low concentration detection of volatile organic compounds. Multi-dimensional CTL test was carried out to analyse the correlation characteristics of heterogeneous analytes among the catalytic activity, selectivity, sensitivity, response/recover time, stability, and photoelectric signals by changing the parameters of wavelength, flow rate, temperature, and response time under the optimal conditions (280 mL/min, 180ºC, and 480 nm). Due to noise interference received by the CTL signal, the weak CTL signal was filtered based on the time-frequency characteristics of the CTL pattern signal power frequency interference and background noise. Next, this study also studied the mechanism action of the cataluminescence sensor based on LaCO 3 OH microspheres for gas detection, including ethyl ether, acetone, chloroform, and formaldehyde. The principal component analysis (PCA) algorithm was adopted to analyse the CTL patterns, after threshold filtering, the total variance was improved from 89.23% to 98.78% and each vapour gave its unique CTL patterns. Moreover, clustering and identification are discussed to analyse the results, including Hierarchical Cluster Analysis (HCA) and Radial Basis Function Neural Networks (RBFNN), was also discussed. The excellent cluster and recognition ability indicate the feasibility of this CTL sensor for volatile compound determination. • A LaCO 3 OH-microspheres-based cataluminescence sensor was developed for the detection of VOCs firstly. • Multi-dimensional analytes test was carried out among the catalytic activity, selectivity, sensitivity, response/recover time, stability, and photoelectric signals. • Studied the mechanism action of the cataluminescence sensor based on LaCO 3 OH microspheres for gas detection. • The total variance of PCA increased from 89.23% to 98.78% after filtering out the background noise of CTL signal. [ABSTRACT FROM AUTHOR]

• The CTL sensor instrument could response to ethyl ether under 180 °C, which was lower than most of the reported CTL reaction temperatures. • The linear detection range was wide, ranging from 10 ppm to 5800 ppm (R = 0.9978, n = 7), and the detection limit was also low (4.3 ppm). • The CTL sensor showed the response time of 4 s and recovery time of 8 s, which was relatively short. • The pattern recognition results showed the analytes could be classified clearly. The low reaction temperature, excellent sensitivity, selectivity, stability and recognition performance indicated this CTL sensor was ideal for gas contaminants detection in confined spaces for the Internet of Things. Gaseous cataluminescence (CTL) sensor instrument was developed for detecting and measuring pernicious gases such as ethyl ether, acetone, n-hexane, chloroform by using aluminum/iron oxides composites. The materials synthesis, apparatus and software, optimal conditions (flow rate, wavelength, temperature and concentration), selectivity and stability were thoroughly studied. The results indicated the CTL sensor instrument could response to ethyl ether under 180 °C, which was lower than most of the reported CTL reaction temperatures. In addition, the results showed that the linear detection range was wide, ranging from 10 ppm to 5800 ppm (R = 0.9978, n = 7), and the detection limit was also low (4.3 ppm). Moreover, for ethyl ether detection, the CTL sensor showed the response time of 4 s and recovery time of 8 s, which was relatively short. The pattern recognition methods included PCA, KPCA were selected for evaluating the recognition performance of this CTL sensor, results showed the analytes could be classified clearly. The low reaction temperature, excellent sensitivity, selectivity, stability and recognition performance indicated this CTL sensor was ideal for gas contaminants detection in confined spaces for the Internet of Things. [ABSTRACT FROM AUTHOR]

Highlights • The 3D ZZFO/GF was used as peroxidase mimetics for colorimetric detection of HQ. • 3D GF prevented the aggregation of nanoparticles and provided high surface area. • The ZZFO heterostructures enhanced the catalytic efficiency. • This colorimetric method was successfully applied to detect HQ in local river water. Abstract The 3D ZnO/ZnFe 2 O 4 /graphene foam (ZZFO/GF) was successfully prepared by template method and hydrothermal process as a sensing platform for colorimetric detection of hydroquinone (HQ). It is found that the foam exhibited improved peroxidase-like activity that could quickly catalyze 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 and produced a blue color, which can be observed by naked eyes. And the HQ was detected by means of fading the color of the oxTMB, which is a sensitive and simple colorimetric method that is rarely used for detection of HQ. Therefore, a simple, sensitive and selective sensing platform was established. A good linear range from 0 to 150 μM and low detection limit of 3.75 μM was achieved. Furthermore, the materials could be easily recollected by applying a magnetic field. This method exhibited practical potential in environmental pollutant analysis and actual detection of HQ in local river water was achieved. [ABSTRACT FROM AUTHOR]

Accurate determination of highly toxic organic pollutants in the water environment is urgent for the protection of environment and human health. Nevertheless, the development of sensitive nanomaterials for p-nitrophenol (PNP) and o-nitrophenol (ONP) electroanalysis remains a big challenge due to the electrochemical redox inertness of organics, which requires the nanomaterials to own considerable catalytic performance. In this work, FeSe 2 with high electronic conductivity and large active area was successfully prepared by hydrothermal synthesis and thermally induced selenization method. The results under the optimized conditions show that the FeSe 2 modified electrode exhibits high sensitivity (0.397 and 0.377 μA μM−1) and low detection limit (0.030 and 0.036 μM) for PNP and ONP, respectively. Besides, the catalytic rate constant, diffusion coefficient and adsorption capacity determined by chronoamperometry and adsorption experiments are 4745.06 M−1 s−1, 2.98 × 10−4 cm2 s−1 and 5.81 mg g−1, respectively, which indicate that the impressive electrochemical behavior of the prepared electrode should attribute to the combined effect of adsorption and catalysis. Moreover, the constructed high-efficiency sensor exhibits superior selectivity, stability, reproducibility, and also realizes the electrochemical detection of organic pollutants in subsidence area water samples. [Display omitted] • Combining hydrothermal method and thermally induced selenization, FeSe 2 was successfully prepared. • Hypersensitive detection of PNP and ONP was achieved by FeSe 2. • The impressive sensitivities for PNP and ONP are 0.397 and 0.377 μA μM−1, respectively. • The sensor exhibits high anti-interference and robust stability. • The synergistic effect of adsorption and catalysis improves the sensitivity of detection. [ABSTRACT FROM AUTHOR]

• Simple fabrication of small sized Co 3 O 4 /ZnO nanocomposite with oxygen vacancy. • Surface abundant oxygen vacancy enhanced the sensitivity of electroanalysis. • Co 3 O 4 /ZnO achieves high sensitivity (504.74 μA cm−2 μM-1) for Hg(II) detection. • The sensor exhibits high anti-interference and robust stability. Metal-oxide based nanocomposites have superior benefits to fabricate sensing interface for electroanalysis of heavy metal ions (HMIs) due to the introduction of various advantages (i.e. environmentally friendly, low-cost and high activity) into one material. Herein, Co 3 O 4 /ZnO nanocomposite with small size (sub-40 nm) and abundant oxygen vacancy was successfully prepared through one-step hydrothermal synthesis and subsequent annealing treatment, as well as the engineering of Co-Zn molar ratio. Moreover, the loose structure of Co 3 O 4 /ZnO nanocomposite can effectively improve the exposure of active sites on surface and enhance mass transfer. As a result, the as-obtained Co 3 O 4 /ZnO sensor has an impressive performance with sensitivity of 504.74 μA μM-1 cm-2 for electroanalysis of Hg(II) by square wave anodic stripping voltammetry (SWASV). Otherwise, diverse detection performances of the product with different Co:Zn molar ratio are investigated, proving the superiority for constructing Co 3 O 4 /ZnO sensor with molar ratio of 2Co/Zn. In addition, the electroanalytical behavior of the proposed sensors toward Hg(II) in subsidence area water was also realized with considerable result. By designing multifunctional nanocomposite with bimetal oxide nanomaterials, this work will provide a novel strategy to gain nanocomposite with controlling morphology and enriching oxygen vacancies, which are expected to be excellent candidate electrode materials for electroanalysis. [ABSTRACT FROM AUTHOR]