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Carbon dots (CDs) samples were synthesized from orange peel waste (OPW) via a simple and eco‐friendly hydrothermal carbonization (HTC) and electrochemical (EC) bottom‐up synthesis integrated approach. The comprehensive chemical‐physical characterization of CDs samples, carried out by various techniques such as TEM, EDX, XRD, FT‐IR, underlined their morphological and microstructural features. The CDs exhibited attractive electrochemical properties, and thus an electrochemical sensor by modifying a screen printed carbon electrode (CDs/SPCE) for the detection of nitrobenzene (NB) in water was developed. Electroanalytical performances of CDs/SPCE sensor using differential pulse voltammetry (DPV) demonstrated its high sensitivity (9.36 μA μM−1 cm−2) towards NB in a wide linear dynamic range (0.1–2000 μM) and a low limit of detection (LOD=13 nM). The electrochemical sensor also shown high selectivity, long‐term stability, and repeatability. This paper might open the way to a new synergistic HTC‐EC approach for the synthesis of CDs from waste biomass material and their advanced application in highly efficient electrochemical sensors. [ABSTRACT FROM AUTHOR]

In the present work, a study was carried out with the aim of enhancing the performance of electrochemical biosensors based on Co3O4:Fe2O3 heterojunctions. Specifically, the redox behavior of screen–printed carbon electrodes (SPCEs) modified with Co3O4:Fe2O3 (0.5 wt%:x wt%) nanocomposites, where x ranged from 0.1 to 0.5 wt%, was examined in detail. The hybrid nanocomposites were synthesized using the sol-gel auto-combustion method. Several characterization methods were performed to investigate the morphology, microstructure, and surface area of the pure Co3O4, pure Fe2O3, and the synthesized Co3O4:Fe2O3 nanocomposites. Using cyclic voltammetry (CV) tests, the electrochemical behavior of the modified electrodes toward the dopamine (DA) molecules was investigated. The modified Co3O4:Fe2O3, (0.5 wt%, x = 0.4 wt%)/SPCE resulted in a sensor with the best electrochemical performance toward DA. A high linear relationship between DA concentrations and the faradic current variation (ipa (μA) = 0.0736 + 0.1031 CDA (μA) and R2 = 0.99) was found in the range of 10–100 μM. The sensitivity value was computed to be 0.604 µA µM−1cm−2 and the limit of detection (LOD) 0.24 µM. Based on the characterization and electrochemical results, it can be suggested that the formation of Co3O4:Fe2O3 heterostructures provides a large specific surface area, an increased number of electroactive sites at the metal oxide interface and a p–n heterojunction, thus ensuring a remarkable enhancement in the electrochemical response towards DA. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor for the determination of nitrites based on the modified screen‐printed electrode (SPCE) by Zn‐bidentate Schiff base complexes (ZnLX2) is presented. ZnLX2 complexes have been synthesized and characterized using several morphological and microstructural techniques such as scanning electron microscopy (SEM), X‐ray powder diffraction (XRD), and fourier transformed‐infrared (FT‐IR) spectroscopy. Cyclic voltammetry (CVs) proved the good electrochemical performances of the ZnLX2/SPCE for nitrite ions determination. The influence of pH, scan rate, nitrite concentration, and interfering ions was investigated. After optimization of the operating parameters, the developed ZnLX2/SPCE sensor displayed two linear relationships between response current and nitrite concentration in the overall range 2–4838 μM and a lower detection limit estimated to be 0.78 μM based on 3σ/m. Finally, the analytical application of the developed sensor was evaluated to quantify nitrite in a real sample of mineral water. Results obtained demonstrate that the ZnLX2/SPCE electrochemical sensor provided an effective tool for the detection of nitrite ions. [ABSTRACT FROM AUTHOR]

In this article, the electrochemical monitoring of phenol (Ph) in water by using a nanostructured MnO2-modified screen-printed carbon electrode (MnO2-SPCE) is reported. MnO2 nanoparticles were synthesized by the redox-precipitation method. Morphological, textural, and microstructural characteristics were investigated by scanning electron microscopy (SEM), X-ray diffraction, Raman, Brunauer–Emmett–Teller (BET) surface area, and pore volume analyses. Electrochemical properties of the modified MnO2-SPCE electrode have been investigated by cyclic voltammetry and linear sweep voltammetry. The detection of Ph in water by the developed sensor was exploited using square wave voltammetry and chronoamperometry. The sensor showed good characteristics, such as simple fabrication, low cost, good sensitivity, stability, reproducibility, and selectivity, against inorganic analytes and other phenolic compounds. The reported results demonstrated the great potential of nanostructured MnO2 in developing high performances electrochemical sensors to be utilized in the field of environmental pollution monitoring. [ABSTRACT FROM AUTHOR]

Cover Feature: Voltammetric Sensor Based on Waste-Derived Carbon Nanodots for Enhanced Detection of Nitrobenzene (ChemElectroChem 13/2023) Carbon nanodots, electrochemical sensor, electrochemical bottom-up synthesis, waste valorization, nitrobenzene Keywords: carbon nanodots; electrochemical sensor; electrochemical bottom-up synthesis; waste valorization; nitrobenzene EN carbon nanodots electrochemical sensor electrochemical bottom-up synthesis waste valorization nitrobenzene 1 1 1 07/05/23 20230703 NES 230703 B The Cover Feature b shows groundwater contaminated by environmental pollutants and how a sensor modified by an improved waste is helpful to estimate the presence of contaminants in it. [Extracted from the article]

Iron oxide nanostructures (IONs) in combination with graphene or its derivatives-e.g., graphene oxide and reduced graphene oxide-hold great promise toward engineering of efficient nanocomposites for enhancing the performance of advanced devices in many applicative fields. Due to the peculiar electrical and electrocatalytic properties displayed by composite structures in nanoscale dimensions, increasing efforts have been directed in recent years toward tailoring the properties of IONs-graphene based nanocomposites for developing more efficient electrochemical sensors. In the present feature paper, we first reviewed the various routes for synthesizing IONs-graphene nanostructures, highlighting advantages, disadvantages and the key synthesis parameters for each method. Then, a comprehensive discussion is presented in the case of application of IONs-graphene based composites in electrochemical sensors for the determination of various kinds of (bio)chemical substances. [ABSTRACT FROM AUTHOR]

A planar electrochemical sensor, based on flower-like CuO nanostructures growth 'in situ' on a commercial screen printed carbon electrode, was fabricated by an easy and effective technique and employed for the non-enzymatic determination of glucose. The prepared CuO nanostructures were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The carbon electrode modification with CuO was optimized by investigating the effect of the number of deposition cycles of precursor and their concentration. The electrodes modified by in situ growth of CuO were compared to an electrode prepared by simple deposition of CuO powder previously synthesized by the same technique. Cyclic voltammetric and chronoamperometric tests demonstrated that the in situ growth of CuO leads to excellent electrochemical performance toward glucose oxidation in 0.1 M KOH solution. The best sensor, if operated at an applied potential of 0.6 V, has a sensitivity of 1460 μA·mM·cm and a 2.5 μM detection limit (at an S/N ratio of 3). Tests carried out within six months revealed an excellent long-term stability. This suggests that the method applied to modify the carbon electrode represents a useful tool for fabrication of an inexpensive and reliable non-enzymatic glucose sensor. [ABSTRACT FROM AUTHOR]

This paper demonstrates an effective method of monitoring glucose in fermentation processes based on the development of enzyme-free glucose electrochemical sensors. The sensing electrodes were manufactured by preparing size-controlled Au nanoparticles (NPs), in the form of colloidal solutions, which were dispersed on TiO substrates, and then deposited on commercial carbon screen printed electrodes. The as-synthesized samples were fully characterized by transmission electron microscopy, X-ray diffraction, atomic absorption spectroscopy, and UV-visible diffuse reflectance spectroscopy to obtain information about their morphological, structural, and electronic properties. Particularly, the ability to control the size of Au NPs in the colloidal solution by using different reducing agents and stabilizers is presented here. The Au/TiO-based modified sensors were assembled and tested for glucose monitoring in an alkaline solution. Results of cyclic voltammetry showed the high electrocatalytic activity of these sensors toward glucose oxidation, whereas no response was detected toward ethanol. This suggests the possibility of using this type of sensor for glucose monitoring in the fermentation processes without ethanol interference. The efficient sensing properties of Au NP-embedded TiO composites may be ascribed to the higher electrocatalytic activity of smaller Au NPs stabilized on TiO. [ABSTRACT FROM AUTHOR]

A novel bidentate Schiff base (L) is here proposed for the detection of Zn ions in water. The structure of the synthesized Schiff base L was characterized by FT-IR, 1H NMR and 13C NMR. Optical characteristics were addressed by UV-Visible spectroscopy and Photoluminescence (PL) measurements. PL demonstrated that L displays a "turn-off" type fluorescence quenching in the presence of Zn2+ ion in aqueous solution, indicating its ability to preferentially coordinate this ion. Based on these findings, an L-M (where M is a suitable membrane) modified screen-printed carbon electrode (SPCE) was developed to evaluate the electrochemical behavior of the Schiff base (L) with the final objective of undertaking the electroanalytical determination of Zn ions in water. Using various electrochemical techniques, the modified L-M/SPCE sensor demonstrates high sensitivity and selectivity to Zn ions over some common interferents ions, such as Ca2+, Mg2+, K+, Ni++ and Cd++. The potentiometric response of the L-M/SPCE sensor to Zn ions was found to be linear over a relatively wide concentration range from 1 μM to 100 mM. [ABSTRACT FROM AUTHOR]

The rapid growth of research in electrochemistry in the last decade has resulted in a significant advancement in exploiting electrochemical strategies for assessing biological substances. Among these, amino acids are of utmost interest due to their key role in human health. Indeed, an unbalanced amino acid level is the origin of several metabolic and genetic diseases, which has led to a great need for effective and reliable evaluation methods. This review is an effort to summarize and present both challenges and achievements in electrochemical amino acid sensing from the last decade (from 2010 onwards) to show where limitations and advantages stem from. In this review, we place special emphasis on five well-known electroactive amino acids, namely cysteine, tyrosine, tryptophan, methionine and histidine. The recent research and achievements in this area and significant performance metrics of the proposed electrochemical sensors, including the limit of detection, sensitivity, stability, linear dynamic range(s) and applicability in real sample analysis, are summarized and presented in separate sections. More than 400 recent scientific studies were included in this review to portray a rich set of ideas and exemplify the capabilities of the electrochemical strategies to detect these essential biomolecules at trace and even ultra-trace levels. Finally, we discuss, in the last section, the remaining issues and the opportunities to push the boundaries of our knowledge in amino acid electrochemistry even further. [ABSTRACT FROM AUTHOR]

The concentration of sodium and potassium ions in biological fluids, such as blood, urine and sweat, is indicative of several basic body function conditions. Therefore, the development of simple methods able to detect these alkaline ions is of outmost importance. In this study, we explored the electrochemical and optical properties of graphene quantum dots (GQDs) combined with the selective chelating ability of the crown ethers 15-crown-5 and 18-crown-6, with the final aim to propose novel composites for the effective detection of these ions. The results obtained comparing the performances of the single GQDs and crown ethers with those of the GQDs-15-crown-5 and GQDs-18-crown-6 composites, have demonstrated the superior properties of these latter. Electrochemical investigation showed that the GQDs based composites can be exploited for the potentiometric detection of Na+ and K+ ions, but selectivity still remains a concern. The nanocomposites showed the characteristic fluorescence emissions of GQDs and crown ethers. The GQDs-18-crown-6 composite exhibited ratiometric fluorescence emission behavior with the variation of K+ concentration, demonstrating its promising properties for the development of a selective fluorescent method for potassium determination. [ABSTRACT FROM AUTHOR]

Pure, mixed and doped metal oxides (MOX) have attracted great interest for the development of electrical and electrochemical sensors since they are cheaper, faster, easier to operate and capable of online analysis and real-time identification. This review focuses on highly sensitive chemoresistive type sensors based on doped-SnO2, RhO, ZnO-Ca, Smx-CoFe2−xO4 semiconductors used to detect toxic gases (H2, CO, NO2) and volatile organic compounds (VOCs) (e.g., acetone, ethanol) in monitoring of gaseous markers in the breath of patients with specific pathologies and for environmental pollution control. Interesting results about the monitoring of biochemical substances as dopamine, epinephrine, serotonin and glucose have been also reported using electrochemical sensors based on hybrid MOX nanocomposite modified glassy carbon and screen-printed carbon electrodes. The fundamental sensing mechanisms and commercial limitations of the MOX-based electrical and electrochemical sensors are discussed providing research directions to bridge the existing gap between new sensing concepts and real-world analytical applications. [ABSTRACT FROM AUTHOR]

The room-temperature synthesis of silver (AgNPs) and gold (AuNPs) nanoparticles from aqueous solution of AgNO3 and HAuCl4 respectively, using Rumex roseus (RR) plant extract as a reducing agent, is reported here for the first time. The nanoparticles obtained were characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The formation of nanoparticles with spherical-shaped morphology was verified by TEM and confirmed by UV-Vis spectroscopy through the analysis of Ag and Au plasmon resonance peak and DLS measurements. New electrochemical sensors have been developed by employing the synthesized Ag and Au nanoparticles as modifiers of glassy carbon electrode (GCE) and screen-printed carbon electrode (SPCE), respectively. The AgNPs-modified GCE was investigated for the electrochemical determination of hydrogen peroxide (H2O2). Further enhancement of electrochemical performances was obtained using a nanocomposite made of AgNPs and reduced graphene oxide (rGO)-modified GCE. The AuNPs-SPCE sensor was instead tested in the electrochemical sensing of riboflavin (RF). To our knowledge, this is the first paper reporting Rumex roseus plant extract as a source for the synthesis of metal nanoparticles and their use for developing simple, sensitive and reliable electrochemical sensors for H2O2 and RF. [ABSTRACT FROM AUTHOR]

The preparation and characterization of a hybrid composite, based on carbon cloth (CC) matrix functionalized with two-dimensional (2D) MoS2 flakes and MoO3, and its use for developing an electrochemical sensor for the determination of riboflavin (RF) is here reported. The 2D-MoS2-MoO3CC composite was prepared by depositing 2D-MoS2 nanosheets, obtained by liquid phase exfoliation (LPE), on the surface of a carbon cloth fiber network, previously functionalized with a layer of molybdenum oxide (α-MoO3) by radio-frequency magnetron reactive sputtering technique. The 2D-MoS2-MoO3CC composite was characterized by scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX), and Raman spectroscopy. An electrochemical sensor has been then fabricated by fixing a slice of the 2D-MoS2-MoO3CC composite on the working electrode of a screen-printed carbon electrode (SPCE). The 2D-MoS2-MoO3-CC/SPCE sensor display good electrochemical characteristics which have been exploited, for the first time, in the electroanalytical determination of riboflavin (RF). The sensitivity to RF, equal to 0.67 µA mM−1 in the linear range from 2 to 40 µM, and a limit of detection (LOD) of 1.5 µM at S/N = 3, demonstrate the promising characteristics of the proposed 2D-MoS2-MoO3-CC/SPCE electrochemical sensor for the determination of riboflavin. [ABSTRACT FROM AUTHOR]

Mo-based layered nanostructures are two-dimensional (2D) nanomaterials with outstanding characteristics and very promising electrochemical properties. These materials comprise nanosheets of molybdenum (Mo) oxides (MoO2 and MoO3), dichalcogenides (MoS2, MoSe2, MoTe2), and carbides (MoC2), which find application in electrochemical devices for energy storage and generation. In this feature paper, we present the most relevant characteristics of such Mo-based layered compounds and their use as electrode materials in electrochemical sensors. In particular, the aspects related to synthesis methods, structural and electronic characteristics, and the relevant electrochemical properties, together with applications in the specific field of electrochemical biomolecule sensing, are reviewed. The main features, along with the current status, trends, and potentialities for biomedical sensing applications, are described, highlighting the peculiar properties of Mo-based 2D-nanomaterials in this field. [ABSTRACT FROM AUTHOR]

Sensing properties of chemical sensors based on ternary hydroxyapatite-graphene-multiwalled carbon nanotube (HA-GN-MWCNT) nanocomposite in the detection of chemical substances representing risk factors for sudden infant death syndrome (SIDS), have been evaluated. Characterization data of the synthesized composite have shown that the graphene-MWCNT network serves as a matrix to uniformly disperse the hydroxyapatite nanoparticles and provide suitable electrical properties required for developing novel electrochemical and conductometric sensors. A HA-GN-MWCNT composite-modified glassy carbon electrode (HA-GN-MWCNT/GCE) has been fabricated and tested for the simultaneous monitoring of nicotine and caffeine by cyclic voltammetry (CV) and square wave voltammetry (SWV), whereas a HA-GN-MWCNT conductive gas sensor has been tested for the detection of CO2 in ambient air. Reported results suggest that the synergic combination of the chemical properties of HA and electrical/electrochemical characteristics of the mixed graphene-MWCNT network play a prominent role in enhancing the electrochemical and gas sensing behavior of the ternary HA-GN-MWCNT hybrid nanostructure. The high performances of the developed sensors make them suitable for monitoring unhealthy actions (e.g., smoking, drinking coffee) in breastfeeding women and environmental factors (bad air quality), which are associated with an enhanced risk for SIDS. [ABSTRACT FROM AUTHOR]

In this paper, nanostructured perovskite-type Ln FeO 3 (Ln = Nd, Sm) oxides were synthesized by thermal treatment method (TTM). Characterization analysis conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM) and micro-Raman spectroscopy, have confirmed the perovskite structure of the synthesized nanomaterials. To study the effects of Nd and Sm lanthanides substitution at the A-site on the chemical sensing performance, conductometric and electrochemical sensors based on the synthesized Ln FeO 3 samples were fabricated. Ln FeO 3 -based conductometric and electrochemical sensors were tested for acetone and dopamine sensing, respectively. The data revealed that Nd and Sm in the A-position lead to a significant influence in the gas sensing and electrochemical properties of perovskite Ln FeO 3 samples. In particular, it has been demonstrated the good gas sensing characteristics of SmFeO 3 for acetone gas (Response = R/R 0 = 8.3–20 ppm acetone at 200 °C), whereas NdFeO 3 displayed better performance as electrode for the electrochemical detection of dopamine reaching a low detection limit (LOD) of 270 nM at S/N = 3. The electrical and electrochemical characteristics of the perovskite Ln FeO 3 samples were discussed in detail with respect to their chemical composition and microstructure. Image 1 • Perovskite-type Ln FeO 3 (Ln = Nd, Sm) oxides were prepared by thermal treatment method. • Ln FeO 3 -based conductometric and electrochemical sensors were tested for acetone and dopamine sensing, respectively. • The data revealed that Nd and Sm in the A-position lead to a significant influence in the gas sensing. • SmFeO 3 displayed good gas sensing characteristics towards acetone. • NdFeO 3 possesses better electrochemical performances towards dopamine detection than SmFeO 3. [ABSTRACT FROM AUTHOR]

[Display omitted] • This study explores THP's potential in H 2 O 2 detection for the first time. • The developed sensor shows a low limit of detection of 144 nM. • Promising results highlight potential in biomedical diagnostics. Hydrogen peroxide (H 2 O 2) detection is paramount in biological and clinical domains due to its pivotal role in various physiological and pathological processes. This molecule is a crucial metabolite and effector in cellular redox mechanisms, influencing diverse cellular signaling pathways and bolstering the body's defense mechanisms against infection and oxidative stress. Organic molecule-based electrodes present unique advantages such as operational versatility and scalability, rendering them attractive candidates for sensor development across diverse fields encompassing food safety, healthcare, and environmental monitoring. This study explores the electrochemical properties of a tris(3-hydroxypyridin-4-one) THP, which has been unexplored in electrochemical sensing. Leveraging THP's chelating properties, we aimed to develop an electrochemical probe for hydrogen peroxide detection. Our investigations reveal promising results, with the developed sensor exhibiting a low limit of detection (LOD) of 144 nM, underscoring its potential utility in sensitive and selective H 2 O 2 detection applications. In addition, the new sensor was also tested on fetal bovine serum (FBS) to emphasize future applications on biological matrices. This research signifies a significant stride in advancing electrochemical sensor technologies for hydrogen peroxide detection with several novelties related to the usage of THP, such as high sensitivity and selectivity, performance in biological matrices, repeatability, stability, and reproducibility, economical and practical advantages. This research opens new avenues for enhanced biomedical diagnostics and therapeutic interventions. [ABSTRACT FROM AUTHOR]

[Display omitted] • SCCNT were coated by ALD with nanometric NiO films of different thickness. • SCCNT/NiO-based electrochemical sensors displayed high sensitivity to lactic acid. • The developed SCCNT/NiO sensors were suitable for the lactic acid quantification in saliva. NiO-coated stacked-cut carbon nanotubes (NiO/SCCNT) nanocomposites were synthesized via atomic layer deposition (ALD), coating the CNT core walls with a shell of NiO at different thickness varying NiO ALD cycles (0, 50, 200, and 700). The as-prepared core–shell composite nanomaterials were applied as electrode materials for modifying screen-printed carbon electrodes (SPCE) for the non-enzymatic electrochemical detection of lactate (LA). Electrochemical tests performed by CV and EIS demonstrated the reduced charge transfer resistance in NiO(x)/CNT-SPCE compared to pristine CNT-SPCE configuration, and the pronounced dependence of electrochemical behavior on NiO coating thickness. Notably, the NiO/CNT composite with 200 ALD cycles exhibited superior electrochemical properties for the electrooxidation of lactate. The developed sensor showed high sensitivity to LA, (138.44 µA mM−1 cm−2 in the 0–4 mM range). The limit of detection (LOD) values stood at 0.067 mM (considering the signal-to-noise ratio of S/N=3). The sensor showcased several advantages including a conductive supporting carbon material, impressive sensitivity, selectivity, stability, and reproducibility, thereby enabling rapid and precise lactate quantification in salivary real samples. [ABSTRACT FROM AUTHOR]

• Layered molybdenum disulfide (2D-MoS 2) nanosheets of different size, < L >, and number of layers, < N >, were prepared via liquid cascade centrifugation (LCC). • Dopamine (DA) and riboflavin (RF) were tested for the first time to investigate the role of < N > and < L > of MoS 2 nanosheets. • The electro-oxidation of RF was found to be largely promoted on the 2D-MoS 2 -based electrode with the smaller lateral size and minor number of layers. In this paper, layered molybdenum disulfide (2D-MoS 2) nanosheets of different size and number of layers were prepared via liquid cascade centrifugation (LCC) and their microstructural, morphological and electrochemical characteristics for the detection of dopamine (DA) and riboflavin (RF) were investigated. The microstructural and morphological characteristics of 2D-MoS 2 nanosheets obtained at different centrifugation rates were evaluated by UV-Vis, Raman spectroscopy, and SEM analysis. The 2D-MoS 2 nanosheets obtained showed a monotonic decrease of average lateral sheet size < L > and number of layers < N > with the increase of the centrifugation speed. Screen printed carbon electrodes (SPCE) were modified by drop casting on their surfaces 2D-MoS 2 nanosheets from aqueous dispersions. The electrochemical properties of the modified 2D-MoS 2 /SPCE were assessed by electrical impedance spectroscopy and cyclic voltammetry in [Fe (CN) 6 ]3−/4− redox probe. DA and RF were tested to investigate the role of < N > and < L > of MoS 2 nanosheets in the electrochemical sensing of these two biomolecules. Results have shown no significant variations in the electrochemical parameters for DA sensing using the different modified electrodes. In contrast, the electro-oxidation of RF was found to be largely promoted on the 2D-MoS 2 -based electrode with smaller lateral size and minor number of layers, demonstrating the feasibility of tuning the electrochemical properties of 2D-MoS 2 nanosheets by modifying their geometric features. The study proposes LCC as an alternative promising technique for preparing nanomaterials with enhanced performances for developing electrochemical sensors for biomolecules. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The light-enhanced NO2 sensing behavior of mesoporous In2O3 is measured and interpreted by means of a new sensing model. The model aims at explaining (i) the drop in electronic resistance of n-type semiconducting In2O3 under UV light exposure, (ii) the light-enhanced reaction to oxidizing gases, and (iii) the faster reaction and regeneration in mesoporous In2O3 as compared to non-porous material. Contrary to the conventional double Schottky model the dominating factor for the change in resistance is a change of oxygen vacancy donor states (0.18eV below the conduction band) in the bulk phase due to photoreduction, instead of chemisorption. For the faster reaction and regeneration we propose an explanation based on enhanced oxygen diffusion in the In2O3 crystal lattice, specifically dominant in the mesoporous structure. The response of ordered mesoporous In2O3 to NO2 is stronger than in case of unstructured bulk material (with an average grain size of ca. 40nm). The reaction is significantly accelerated by illuminating the samples with UV light. However, the response of the mesoporous material is weaker in the illuminated case. [Copyright &y& Elsevier]

A non-enzymatic electrochemical sensor based on cuprous oxide nanocubes (Cu 2 O-NC) has been developed. Cu 2 O-NC samples have been synthesized using a wet precipitation technique under different precipitation temperatures (25 and 60 °C). The samples were characterized by XRD (X-ray Diffraction), UV–visible Diffuse Reflectance Spectroscopy (UV–Vis DRS) and Scanning Electron Microscopy (SEM). Screen-printed carbon electrodes (SPCE) have been modified by casting the synthesized Cu 2 O-NC. The fabricated Cu 2 O-NC-SPCE sensor prepared at 25 °C provided the best sensing performance toward glucose, with a sensitivity of 1040 μA/mM cm−2 in the linear range from 0.007 to 4.5 mM, and a detection limit of 3.1 μM (S/N = 3). Cu 2 O-NC-SPCE electrodes were also evaluated for the amperometric determination of glucose. Testing results showed a satisfactory stability toward glucose sensing and selectivity against other sugars and ethanol, suggesting that the SPCE modification with Cu 2 O-NC could be a simple way to fabricate inexpensive and reliable sensors to monitor glucose in bio-fermentation processes. • Non-enzymatic electrochemical sensor based on cuprous oxide nanocubes (Cu 2 O-NC). • Monitoring of glucose in bio-fermentation processes by means of electrochemical sensors. • Cu 2 O-NC modified SPCE exhibits good sensing performance toward glucose monitoring. • Satisfactory stability and selectivity against other sugars and ethanol. • Simple way to fabricate inexpensive and reliable glucose sensors in industrial processes. [ABSTRACT FROM AUTHOR]