M.M. Alam

Fabrication of selective chemical sensor with ternary ZnO/SnO2/Yb2O3 nanoparticles

Construction of highly efficient toxic chemical sensors is the key approach for the determination of carcinogenic chemicals in the environment and ecosystem. We report here, an efficient acetone chemical sensor based on the analytical performances such as sensitivity, lower-detection limit, reproducibility, and good linearity. The proposed acetone-detecting electrode was introduced by the implementation of ZnO/SnO2/Yb2O3 nanoparticles (NPs) as a successful electron mediator with glassy carbon electrode (GCE) assembly. The prepared NPs of ZnO/SnO2/Yb2O3 were well crystalline-doped nanomaterial and produced by implementation of hydrothermal procedure at low temperature. The conventional methods such as Fourier-transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV/vis), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and powder x-ray diffraction (XRD) were utilized for characterization of prepared NPs in terms of morphological, elemental, optical and structural properties. The large linear dynamic range (LDR) of 0.34nmolL-1 to 3.4mmolL-1 with lower detection limit (S/N=3) of 0.05±0.002nmolL-1 and a higher sensitivity of 17.09µAmmolL-1cm-2 were exhibited by lab-made fabricated sensor based on ZnO/SnO2/Yb2O3 NPs for selective acetone detection. In shortly, the ZnO/SnO2/Yb2O3 NPs are utilized as an excellent electron mediator with Nafion/GCE assembly in a chemical sensor for acetone detection even at the very low concentration. Therefore, the chemical sensor is fabricated with ZnO/SnO2/Yb2O3 NPs may be a promising highly sensitive sensor by reliable I-V detection method for the effective detection of hazardous and carcinogenic chemicals in medical as well as health-care fields.

Ethanol sensor development based on ternary-doped metal oxides (CdO/ZnO/Yb2O3) nanosheets for environmental safety

Herein, we report the construction of a dynamic, highly sensitive, stable, reliable, and reproducible selective ethanol sensor based on a ternary metal oxide system of CdO/ZnO/Yb2O3 nanosheets (NSs). The NSs were synthesized by a hydrothermal process in alkaline phases. The morphological and structural characterization of the synthesized NSs were approved using various advantageous and well-established conventional methods such as Fourier-transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV/vis), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and powder X-ray diffraction (XRD). A thin layer of CdO/ZnO/Yb2O3 NSs was deposited onto a glassy carbon electrode (GCE) with conducting binder to produce a working electrode. A calibration plot was obtained and was found to be linear over the ethanol concentration range (linear dynamic range, LDR) from 0.35 nM to 3.5 mM with the detection limit (LoD) of 0.127 ± 0.006 nM and the quantification limit (LoQ) of 0.423 ± 0.02 (signal-to-noise ratio, at the S/N of 3), and the system exhibited a sensitivity of 7.4367 μA mM−1 cm−2. Furthermore, the proposed chemical sensor was successively applied for the detection of ethanol in various environmental samples. This approach was introduced as a well-organized route for efficient ethanol sensor development in environmental and health-care fields in a broad scale.

Fabrication of 4-aminophenol sensor based on hydrothermally prepared ZnO/Yb2O3 nanosheets

In this study, a facile hydrothermal process was used to prepare the NSs of ZnO/Yb2O3 in an alkaline medium (pH ∼ 10.5), at a low temperature. The calcined NSs were characterized by Fourier-transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV/vis), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). A thin layer of NSs was coated on a glassy carbon electrode (GCE) with the help of a nafion conducting binder to be used as a sensor. This assembled sensor was implemented to the successful detection of 4-AP and exhibited good sensitivity (5.063 μA μM−1 cm−2) and a low detection limit (DL = 0.019 ± 0.001 nM at a signal to noise ratio of 3). The calibration plot (attained at a potential of +1.0 V) is linear (r2 = 0.9836) in the concentration range of 0.1 nM to 0.1 mM of 4-AP. Therefore, the chemical sensor fabricated with ZnO/Yb2O3 NSs may be a promising sensitive chemical sensor in a reliable I–V method for the effective detection of hazardous and carcinogenic chemicals in environmental and healthcare sectors on broad scales.

3,4-Diaminotoluene sensor development based on hydrothermally prepared MnCoxOy nanoparticles

A facile hydrothermal process was used to prepare MnCoxOy nanoparticles (NPs) in alkaline medium (pH~10.5) at room temperature. The NPs were characterized by Fourier-transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV/vis), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and powder X-ray diffraction (XRD). A thin layer of NPs film as a chemical sensor was fabricated on a glassy carbon electrode (GCE) with the help of a conducting binder. The sensor was implemented successfully for the detection 3,4-DAT with reliable I-V approach at low potential. The sensor-features include good sensitivity (0.37 mAµmolL-1cm-2), low detection limit (LOD=0.26±0.01 pmolL-1 at a signal to noise ratio of 3), low limit of quantification (LOQ=7.80±0.01 pmolL-1), good reliability, good reproducibility, ease of integration, and long-term stability were investigated. The sensor response towards 3,4-DAT is linear in logarithmic scale over a large concentration range (1.0 pmolL-1 to 1.0 µmolL-1). This work is introduced a route for future sensitive sensor development based on MnCoxOy NPs by reliable I-V method for the detection of hazardous and carcinogenic toxins in environmental and health care fields.

Fabrication of an acetone sensor based on facile ternary MnO2/Gd2O3/SnO2 nanosheets for environmental safety

The facile hydrothermally synthesized (at low temperature, in alkaline medium of pH 10.5) nanosheets (NSs) of MnO2/Gd2O3/SnO2 are well crystalline-doped ternary metal oxides. The prepared sample was characterized via Fourier-transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV/vis), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and powder X-ray diffraction (XRD). A thin layer of NSs was coated on a glassy carbon electrode (GCE) with the help of Nafion conducting binder to obtain a working electrode of a chemical sensor. The proposed chemical sensor was implemented to detect acetone at a low potential via the reliable I–V method. The features of the sensor include good sensitivity (0.1394 μA μM−1 cm−2), low detection limit (LOD = 0.068 ± 0.003 nM, at a signal to noise ratio of 3), low limit of quantification (LOQ = 2.04 ± 0.102 nM), good reliability and reproducibility, ease of integration, and long-term stability. The calibration plot (current vs. concentration at a potential of 1.5 V) is linear (R2 = 0.9510) in the logarithmic scale over a large concentration range (from 0.34 nM to 3.4 mM). Thus, the presented chemical sensor is promising for the effective detection of hazardous and carcinogenic chemicals in ecological as well as environmental fields.

Nitrate detection activity of Cu particles deposited on pencil graphite by fast scan cyclic voltammetry

Electrocatalytic nitrate reduction and sensing activities of Cu deposits from 0.01 M CuSO4 · 5H2O solution by fast scan (1000 mV/s) cyclic voltammetry on pencil graphite (PG) was investigated. The content of Cu particles on PG surface was controlled by fixing the deposition cycles between 0 and −300 mV. The performance of the different Cu/PG electrodes has been explained in terms of reduction current, kinetic order, exchange current density, specific electrical capacitance and nitrate sensing abilities. All these activities were modestly dependent on the content of Cu particles on the PG surface. The minimum catalytic sites on PG surface were generated even by the single Cu deposition cycle. Depending on the Cu content, the electrodes exhibited lowest nitrate detection limits in the range between 1.0 × 10−4 to 1.1 × 10−3 M. The nitrate detection performance of the Cu/PG electrode was justified with the ion chromatographic method.

2-Nitrophenol sensor-based wet-chemically prepared binary doped Co3O4/Al2O3 nanosheets by an electrochemical approach

Herein, the wet-chemical process (co-precipitation) was used to prepare nanosheets (NSs) of Co3O4/Al2O3 in an alkaline medium (pH ∼ 10.5). The synthesized NSs were totally characterized by Fourier-transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV/vis), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (XRD). The synthesized NSs were deposited onto a glassy carbon electrode (GCE) to prepare a very thin layer with a conducting binder for detecting 2-nitrophenol (2-NP) selectively by a reliable electrochemical method. The proposed chemical sensor exhibits good sensitivity (54.9842 μA μM−1 cm−2), long-term stability, and enhanced chemical response by electrochemical approaches. The resultant current is found to be linear over the concentration range (LDR) from 0.01 nM to 0.01 mM. The estimated detection limit (DL) is equal to 1.73 ± 0.02 pM. This study introduces a potential route for future sensitive sensor development with Co3O4/Al2O3 NSs by an electrochemical approach for the selective detection of hazardous and carcinogenic chemicals in environmental and health care fields.

Fabrication of 1,4-dioxane sensor based on microwave assisted PAni-SiO2 nanocomposites

In this study, conducting polyaniline (PAni) and silicon dioxide (SiO2) nanocomposites (NCs) were synthesized for chemical sensing applications by microwave assisted reaction technique. Facile synthesis and characterization of the PAni-SiO2 nanocomposites were investigated in details and discussed in this report. For the potential application, 1,4-dioxane chemical sensor was fabricated with the PAni-SiO2 nanocomposites deposited onto glassy carbon electrode (GCE). A very thin uniform film was deposited onto GCE with nanocomposite by using conducting 5% nafion binder at room conditions. To evaluate the sensor analytical performances, a calibration plot such as current versus concentration of 1,4-dioxane was drawn and calculated the analytical parameters from the slope of calibration curve. Results are found as sensitivity (0.5934 µAµmol-1 L-2 cm-2), detection limit (16.0 ± 0.8 pmol L-1), and quantification limit (LOQ; 53.3 ± 1.5 pmol L-1) in this observation. Considering the linear region in calibration plot, the linear dynamic range of 1,4-dioxane chemical sensor was found (0.12 nmol L-1 ∼ 1.2 mmol L-1). Besides this, the proposed 1,4-dioxane chemical sensor was exhibited good reproducibility, long-term stability, high accuracy in detecting of 1,4-dioxane in real environmental samples. This research is to develop of a selective and an efficient electrochemical sensor. It might be a simple and easy way by applying electrochemical method to ensure the safe and sustainable green environment.

Wet-chemically prepared low-dimensional ZnO/Al2O3/Cr2O3 nanoparticles for xanthine sensor development using an electrochemical method

A reliable xanthine (XNT) chemical sensor was fabricated using a facile wet-chemical method (by co-precipitation) to prepare ZnO/Al2O3/Cr2O3 nanoparticles (NPs) in an alkaline medium at low temperature. Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-vis) were implemented for detailed characterization of the NPs. To fabricate the working electrode as a XNT chemical sensor probe, a glassy carbon electrode (GCE) with a 0.0316 cm2 surface area was coated with an ethanolic slurry of the prepared ZnO/Al2O3/Cr2O3 NPs to make a thin layer and used to analyse XNT in a phosphate buffer system. To evaluate the analytical performances of the XNT chemical sensor, the calibration curve of XNT was plotted as the relationship of current versus the concentration of XNT. The plotted calibration curve was found to be linear over the LDR (linear dynamic range) of 0.05 nM to 5.0 μM. The assembled XNT electrochemical sensor exhibited the highest sensitivity (70.8861 μA μM−1 cm−2), the lowest detection limit (1.34 ± 0.07 pM), good reproducibility performance with high accuracy and long-term stability with standard results under ambient conditions. This is a simple route to selectively detect XNT with wet-chemically prepared co-doped ZnO/Al2O3/Cr2O3 nanomaterials using a reliable electrochemical method at a large scale for safety within healthcare fields.

Selective hydrazine sensor fabrication with facile low-dimensional Fe2O3/CeO2 nanocubes

A facile hydrothermal technique was applied to prepare doped Fe2O3/CeO2 nanocubes (NCs) in alkaline medium at low temperature. The calcined NCs were characterized by Fourier-transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV/vis), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and powder X-ray diffraction (XRD). A chemical sensor was fabricated with a glassy carbon electrode (GCE) modified by deposition of a uniform thin layer of NCs film. The fabricated chemical sensor was used successfully to detect hydrazine selectively by a reliable electrochemical method at lower potential. The sensors analytical performances, including good sensitivity (0.1275 μA μM−1 cm−2), low detection limit (7.45 ± 0.37 pM), broad linear dynamic range (0.02 μM–0.02 M), precious reproducibility, low limit of quantification (0.22 ± 0.01 μM) and long-term stability, were investigated. An efficient hydrazine chemical sensor based on Fe2O3/CeO2 NCs/binder/GCE was developed and performed well in terms of analytical sensing performances as well as being validated for environmental and extracted real samples.