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In this work, new strategies were developed to prepare 1D-V2MoO8 (VMO) rods from 2D V-doped MoSe2 nanosheets (VMoSe2) with good control over morphology and crystallinity by a facile hydrothermal and calcination process. The morphological changes from 2D to 1D rods were controlled by changing the calcination temperature from 300 to 600 °C. The elimination of Se and the incorporation of O into the V-Mo structure were evaluated by TGA, p-XRD, Raman, FE-SEM, EDAX, FE-TEM, and XPS analyses. These results prove that the optimization of the physical parameters leads to changes in the crystal phase and textural properties of the prepared material. The VMoSe2 and its calcined products were investigated as electrochemical sensors for the detection of the antibacterial drug nitrofurantoin (NFT). At a calcination temperature of 500 °C, the modified screen-printed carbon electrodes (SPCE) proved to be an excellent electrochemical sensor for the detection of NFT in neutral media. Under the optimized conditions, VMO-500 °C/SPCE exhibits low detection limit (LOD) (0.015 µM), wide linear ranges (0.1-31, 47-1802 µM), good sensitivity, and selectivity. The proposed sensor was successfully used for the analysis of NFT in real samples with good recovery results. Moreover, the reduction potential of NFT agreed well with the theoretical analysis using quantum chemical calculations, with the B3LYP with 6-31G(d,p) basis set predicting an E0 value of -0.45 V. The interaction between the electrode surface and NFT via the LUMO diagram and the electrostatic potential surface is also discussed.

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Non-thermal plasma (NTP) has been demonstrated as one of the promising technologies that can degrade volatile organic compounds (VOCs) under ambient condition. However, one of the key challenges of VOCs degradation in NTP is its relatively low mineralization rate, which needs to be addressed by introducing catalysts. Therefore, the design and optimization of catalysts have become the focus of NTP coupling catalysis research. In this work, a series of two-dimensional nanosheet Co-Ni metal oxides were synthesized by microwave method and investigated for the catalytic oxidation of benzene in an NTP-catalysis coupling system. Among them, Co2Ni1Ox achieves 60% carbon dioxide (CO2) selectivity (SCO2) when the benzene removal efficiency (REbenzene) reaches more than 99%, which is a significant enhancement compared with the CO2 selectivity obtained without any catalysts (38%) under the same input power. More intriguingly, this SCO2 is also significantly higher than that of single metal oxides, NiO or Co3O4, which is only around 40%. Such improved performance of this binary metal oxide catalyst is uniquely attributed to the synergistic effects of Co and Ni in Co2Ni1Ox catalyst. The introduction of Co2Ni1Ox was found to promote the generation of acrolein significantly, one of the key intermediates found in NTP alone system reported previously, suggest the benzene ring open reaction is promoted. Compared with monometallic oxides NiO and Co3O4, Co2Ni1Ox also shows higher active oxygen proportion, better oxygen mobility, and stronger low-temperature redox capability. The above factors result in the improved catalytic performance of Co2Ni1Ox in the NTP coupling removal of benzene.

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Metal oxides exist in porous media in the form of composite metal oxides, which can significantly affect the transport and transformation of pollutants in the soil environment. In this study, binary metal oxide porous media were prepared to explore the effects of solution chemistry, and the presence of binary metal oxides on the transport of functional group modified polystyrene nanoplastics (PSNPs) in saturated porous media. The results show that the existence of binary metal oxides significantly affects the migration ability of PSNPs in saturated porous media. The increase of ionic strength and the presence of multivalent cations affect the transport capacity of PSNPs in porous media. The types of binary metal oxides affect the migration of PSNPs in saturated porous media. The surface roughness and electrostatic interaction are important factors affecting the retention of PSNPs on the surface of binary metal oxide saturated porous media. The surface morphology has a more far-reaching impact. In addition, DLVO theory cannot fully explain the interaction between PSNPs and saturated porous media in the presence of Al3+. This study's results help provide some theoretical support for the migration of microplastics in the soil environment.

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Enhancing the current signal response for semiconductors is the key factor for designing and fabrication of efficient electrode in electrochemical sensors. By the aid of doping with binary metal oxides, the conductivity of the resultant titanium oxide (TiO2) based nanocomposite will deliver fast electron transfer rate at the heterojunction interface. Herein, by taking advantage of mesoporous structure in TiO2, cubic shaped multivalent cerium oxide (CeO2) was incorporated into the porous cavity by simple ground assisted solvothermal process, which resulted in enormous enhancement in the current response towards detection of 2-aminophenol. The advantage of CeO2 on TiO2 not only involves the loading of binary metal oxide on its mesoporous sites, but also facilitates the formation of CeO2 nanocrystals which induce larger surface area and high electroactive sites with rapid diffusion of target species through pores. As a result, CeO2-TiO2 on modified GC electrode exhibits drastic enhancement in the current response for oxidation of 2-aminophenol with large decrease in the onset potential than TiO2/GC electrode. Furthermore, the CeO2-TiO2 modified electrode shows significant behavior for sensing of 2-aminophenol with wide linear range of 0.01-500 µM. The sensitivity and detection limit were calculated to be 0.603 µA µM cm-2 and 3.5 nM respectively. This work establishes the facile strategy for decoration of binary metal oxide-based nanocomposites as effective electrode and also possible to create new opportunities in the designing and fabrication of variety of efficient electrode in various electrochemical applications.

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Recently, perovskite structure-based metal oxide nanomaterials and their composites opted for electrocatalyst because of its excellent conductivity, unique, and favored electronic structure. In this attempt, herein we prepared the rare earth mixed metal molybdate covered reduced graphene oxide La2(MoO4)3@rGO nanocomposites by a simple hydrothermal method for the sensitive detection of Moxifloxacin hydrochloride (MOF) in pharmaceutical and human urine samples. The various physicochemical analysis such as SEM, TEM, XRD and Raman spectroscopy confirms the successful formation of (La2(MoO4)3@rGO) nanocomposites. Furthermore, the electroanalytical performance of La2(MoO4)3@rGO modified glassy carbon electrode (La2(MoO4)3@rGO/GCE) was analyzed using the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) which shows excellent results with a wide range of 1.0 × 10-8 M to 6.0 × 10-4 M and the detection limit of 2.84 × 10-9 M towards the MOF detection. Furthermore, the developed sensor expressed good selectivity, repeatability, stability and reproducibility. Finally, the real sample analysis of the developed sensor was tested in the MOF tablets and human urine samples, which shows the appreciable recoveries.

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Cervical carcinoma is a kind of common gynecological cancer, the physiopathology of which is consanguineously connected with protein glycosylation and phosphorylation. Here, the magnetic binary metal oxide composites with the functionalization of hydrophilic tripeptide is designed and synthesized for simultaneous enrichment of glycopeptide and phosphopeptide in HeLa cells. Multiple kinds of metal sites realize more comprehensive enrichment of phosphopeptides compared with single metal, and ultra-hydrophilic property of glutathione further endows the composites with excellent affinity towards glycopeptides. The composites exhibited low detection limit (0.5 fmol/µL) and high selectivity (digests of ß-casein and BSA, 1:500, m/m) for phosphopeptides, also showed good enrichment efficiency for glycopeptide including detection limit (0.1 fmol/µL) and selectivity (digests of HRP and BSA, 1:50, m/m). Meanwhile, the composites still possess outstanding enrichment capability towards phosphopeptide and glycopeptide after stored for two months or six consecutive times reuse. Eventually, 1177 phosphopeptides and 438 glycopeptides are identified simultaneously from 100 µg HeLa cell digests. As anticipated, potential biomarkers, such as heat shock protein beta-1, DNA topoisomerase 2-alpha, proliferation marker protein Ki-67 and 60 kDa heat shock protein are detected, suggesting its promising application in discovery and screening of cervical carcinoma.

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Herein, bimetallic Co/Ni-MOF derived hollow NiCo2O4@C composite modified glassy carbon electrode (NiCo2O4@C/GCE) is constructed and applied to simultaneously detect furazolidone (FZD) and chloramphenicol (CAP) for the first time. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy confirm that NiCo2O4@C has hollow and mesoporous structure, abundant carbon matrixes, sufficient oxygen defects and mixed-valence metallic elements. These advantages make NiCo2O4@C/GCE show distinguished electrocatalytic performance toward the simultaneous determination of FZD and CAP. The NiCo2O4@C/GCE shows wide linear ranges of 0.5-240 µM for FZD and 0.5-320 µM for CAP, low limit of detection of 8.47 nM for FZD and 35 nM for CAP. The mechanism studies show that reductions of FZD and CAP on NiCo2O4@C/GCE are both four-electron and four-proton processes. Moreover, the sensor obtains desirable recoveries for the simultaneous determination of FZD (95.85%-103.9%) and CAP (95.72%-104.4%) in milk and honey by standard addition method.

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Nanotechnology has received much attention in treating contaminated waters. In the present study, a facile co-precipitation method was employed to synthesize a novel iron and magnesium based binary metal oxide using a stoichiometrically fixed amount of FeNO3·9H2O and MgNO3·6H2O in a proportion of molar concentration 1:1 and was later evaluated in removing As (III) from contaminated waters. Characterization of the prepared nanomaterial was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX) and ultraviolet-visible spectrophotometry (UV-VIS). Experimental studies on batch scale were carried out, examining the effect of varying initial concentrations of metal, adsorbent dosage, application time and initial pH on removal efficiency. Arsenic removal increased on increasing adsorbent dosage (0.1-1 g/L) but trend reversed on increasing initial arsenic concentration attaining qmax of 263.20 mg/g. Adsorption was quite efficient in pH range 4-8. Freundlich fitted better for adsorption isotherm along with following Pseudo-2nd order kinetics. The reusability and effect of co-existing ions on arsenic adsorption, namely SO42-, CO32- and PO43- were also explored with reusability in 1st and 2nd cycles attained adsorptive removal up to 77% and 64% respectively. The prepared nano-adsorbent showed promising results in terms of high arsenic uptake (qmax of 263.20 mg/g) along with facile and cost-effective synthesis. Thus, the co-precipitation technique used in this work is a simple one step procedure without any use of any precursor as compared to most of the other procedures used for synthesis.

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Real-time monitoring of neurotransmitter levels is of tremendous technological demand, which requires more sensitive and selective sensors over a dynamic concentration range. As a use case, we report yttrium vanadate within three-dimensional graphene aerogel (YVO/GA) as a novel electrocatalyst for detecting dopamine (DA). This synergy effect endows YVO/GA nanocomposite with good electrochemical behaviors for DA detection compared to other electrodes. Benefiting from tailorable properties, it provides a large specific surface area, rapid electron transfer, more active sites, good catalytic activity, synergic effect, and high conductivity. The essential analytical parameters were estimated from the calibration plot, such as a limit of detection (1.5 nM) and sensitivity (7.1 µA µM-1 cm-2) with the YVO/GA sensor probe electrochemical approach. The calibration curve was fitted with the correlation coefficient of 0.994 in the DA concentration range from 0.009 to 83 µM, which is denoted as the linear working range. We further demonstrate the proposed YVO/GA sensor's applicability to detect DA in human serum sample with an acceptable recovery range. Our results imply that the developed sensor could be applied to the early analysis of dementia, psychiatric, and neurodegenerative disorders.

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Rapid-monitoring of drugs has attracted tremendous consideration owing to robust global demand for cost-effective and high effectiveness. Binary metal oxides with various morphology have been reported as electrodes for electrochemical sensor to fulfilling the clinical and enviromental requirements. In this study, strontium tungstate (SrWO4) nanoflakes have been successfully prepared via the facile sonochemical method for the first time. The characteristics of as-prepared SrWO4 are systematically measured by various analytical and spectroscopic methods. The SrWO4 nanoflakes are utilized to modify the electrochemical electrode for the sulfadiazine (SDZ) determination. The SrWO4 modified electrode possesses excellent electrocatalytic activity and high recognition capability for the electrochemical detection of SDZ. Impressively, the as-fabricated SrWO4 modified electrode attainted lowest oxidation peak at +0.93 V (vs Ag/AgCl2) with the limit of detection of 0.009 µM, the sensitivity of 0.123 µA µM-1 cm2 and linear detection range of 0.05-235 µM. The enhanced performance of proposed SrWO4-based sensors could be attributed to the catalytic effect, large surface area, good electrical conductivity and physicochemical nature. Notably, the electrocatalytic performances of the SDZ sensors are good as compared to the previous literature, indicating the significance of the newly designed SrWO4 modified electrode. The real-sample diagnosis by the SDZ detection in environmental sample demonstrates the proposed SrWO4-based sensors with good recovery range.

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In recent years, Fe-based catalysts for the selective catalytic reduction of NO with NH3 (NH3-SCR) have been attracting more attention. In this work, a novel Fe-Sb binary metal oxide catalyst was synthesized using the ethylene glycol assisted co-precipitation method and was characterized using a series of techniques. It was found that the catalyst with a molar ratio of 7:3 (Fe:Sb) displayed the best NH3-SCR activity with 100% conversion of NOx (nitrogen oxides) over a wide temperature window and with good resistance to H2O + SO2 at 250 °C. The X-ray photoelectron spectroscopy (XPS) and in situ diffused reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) of NOx adsorption results suggested that strong electron interactions between Fe and Sb in Fe-O-Sb species existed and electrons of Sb could be transferred to Fe through the 2Fe3+ + Sb3+ ↔ 2Fe2+ + Sb5+ redox cycle. The introduction of Sb significantly improved the adsorption behaviour of NOx species on the Fe0.7Sb0.3Ox surface, which benefitted the adsorption/transformation of NOx, thereby facilitating the NH3-SCR reaction. In addition, the Fe0.7Sb0.3Ox catalyst demonstrated a good tolerance of H2O and SO2, since the decomposition of NH4HSO4 on the catalyst surface was promoted by the introduction of Sb.

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Binary metal oxides (La2O3@SnO2) decorated reduced graphene oxide nanocomposite was synthesized by ultrasound process in an environmentally benign solvent with a working frequency of 25 and 40 kHz (6.5 l200 H, Dakshin, India and maximum input power 210 W). Further, to enhance the electrocatalytic activity, the reduced graphene oxide (rGO) was prepared from graphene oxide by ultrasonication method. As prepared La2O3@SnO2/rGO was scrutinized using XRD, TEM, EDX and quantitative test for the structural and morphology properties. As modified La2O3@SnO2/rGO nanocomposite exhibits better electrochemical activity towards the oxidation of methyl nicotinate with higher anodic current compared to other modified and unmodified electrode for the detection of methyl nicotinate with larger linear range (0.035-522.9 µM) and lower limit of detection (0.0197 µM). In addition, the practical feasibility of the sensor was inspected with biological samples, reveals the acceptable recovery of the sensor in real samples.

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An electrochemical sensor is described for the determination of catechol (CT) based on the nanocomposite of lanthanum cobaltite supported on graphene nanosheets (LaCo/GNS). The nanocomposite was systematically examined by various analytical and spectroscopic methods. The LaCo/GNS-modified electrode exhibites good electrochemical activity towards CT determination compared to other modified and unmodified electrodes. The electrochemical signal was acquired at a redox potential of 0.21 (Epa) and 0.17 (Epc) Volt (vs. Ag/AgCl). The proposed electrode exhibits low detection limit (1.0 nM), wide working range (0.009-132 µM), and good sensitivity (5.68 µA µM-1 cm-2). The electrochemical nanoprobe has good selectivity over potentially interfering compounds. The electrochemical sensor was applied to the analysis of environmental samples with acceptable recovery. Graphical abstractSchematic representation of electrochemical determination of catechol in the environmental sample analysis using lanthanum cobaltite supported on graphene nanosheets.

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Diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug, has been detected in effluents of conventional wastewater treatment plants worldwide. The presence of this compound in various water resources even at very low concentrations poses a big threat both to human health and aquatic ecosystems. In this study, the removal of diclofenac from aqueous solution using Fe-Mn binary oxide (FMBO) adsorbents was investigated. FMBO adsorbents were prepared at varying Fe/Mn molar ratios (1:0, 3:1, and 1:1) through simultaneous oxidation and co-precipitation methods. Batch adsorption experiments were conducted to evaluate the effects of important parameters, such as initial DCF concentration, FMBO dosage, solution pH, and Fe/Mn molar ratio, on DCF removal. Acidic to neutral pH conditions were more favorable for DCF adsorption, while increasing initial DCF concentration and adsorbent dosage resulted in higher DCF removal efficiencies for the three oxides. Lower Fe/Mn molar ratio during FBMO synthesis favored higher DCF removals of up to 99% within a wide pH range. Optimization of operating parameters (initial DCF concentration, FMBO dosage, and solution pH) by Box-Behnken design resulted in up to 28.84 mg g-1 DCF removal for 3:1 FMBO. Freundlich isotherm best described the experimental data, indicating that adsorption occurred on heterogeneous adsorbent surface. Chemisorption was the rate-limiting step of the DCF removal, as best described by the pseudo-second-order kinetic model.

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The construction of efficient and superior nanostructured materials for the precise determination of contaminants that are hazardous to the environment has gained significant attention by the scientific community. In this regard, we fabricated a nanocomposite consisting of praseodymium vanadate (PrVO4; PrV) anchored to sulfur-doped carbon nitride (PrV/SCN) and applied it to the electrochemical detection of the antibiotic drug metronidazole (MTZ). The structural and crystalline features of the as-prepared PrV/SCN nanocomposite were characterized by various analytical and spectroscopic methods. More distinctly, the PrV/SCN nanocomposite-modified glassy carbon electrode (GCE) exhibits an outstanding linear range (0.001-2444 µM), high sensitivity (1.386 µA/µM cm2), low detection limit (0.8 nM), good reproducibility, and strong anti-interference ability. Notably, the PrV/SCN sensor can determine MTZ in spiked urine and water samples with high recoveries, suggesting its feasibility for real-time applications. Our findings establish PrV/SCN as a robust and promising platform for electrochemical detection. This promotes innovative design for the synthesis of novel functional nanocomposites.

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High electrical conductivity and more active sites exposure are crucial for improving the performance of electrocatalyst. Binary metal oxide nanoarray grown on conductive substrate offers a 3D self-supported electrode with a great promise in boosting its performance in enzyme-free glucose sensing. Here, NiMoO4 nanosheet arrays anchored on carbon cloth (NiMoO4 NSA/CC) was prepared via a simple hydrothermal synthesis and used as 3D self-supported electrode for enzyme-free glucose sensing. The morphology and composition of NiMoO4 nanosheet have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The electrochemical results show that NiMoO4 NSA/CC exhibits remarkable high catalytic activity towards glucose oxidation, with a wide linear response ranging from 1 µM to 0.9 mM, a high sensitivity of 4.13 mA/mM·cm2, and a low detection limit of 1 µM (S/N = 3). The enhanced performance might be attributed to the merits of nanosheet arrays with large surface area, self-supported electrode with 3D open network, as well as bimetallic component with high conductivity. Furthermore, NiMoO4 NSA/CC also shows good selectivity and reliability for glucose detection in human serum. This work offers a new pathway for the construction of enzyme-free glucose sensor with high performance. Graphical abstract ᅟ.

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The construction of highly active and stable non-noble metal electrocatalysts for oxygen evolution reaction (OER) is a crucial requirement for green energy utilization. Herein, we report a novel hybrid nanostructure of Zn/Co bimetallic oxide (ZnxCo3-xO4) hollow polyhedron through a pyrolysis-oxidation strategy derived from bimetallic Zn, Co-zeolitic imidazolate frameworks (ZnCo-ZIFs) rhombic polyhedral. Benefiting from the synergistic effects between highly active metal oxide and the unique polyhedron structure, the ZnxCo3-xO4 hollow polyhedron hybrid displayed outstanding electrocatalytic performances in alkaline media. When the ZnxCo3-xO4 polyhedron was employed as electrocatalysts for OER, a potential as low as 1.66 V (vs. RHE) was required to deliver the current density of 10 mA cm-2 in 1 M KOH, and ZnxCo3-xO4 still presented superior activity after continuously working for cyclic voltammetric scanning of 1000 cycles.

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The development of inexpensive, efficient, and environmentally friendly catalysts for oxygen evolution reaction (OER) is of great significant for green energy utilization. Herein, binary metal oxides (MxCo3-xO4, M = Zn, Ni, and Cu) with yolk-shell polyhedron (YSP) structure were fabricated by facile pyrolysis of bimetallic zeolitic imidazolate frameworks (MCo-ZIFs). Benefiting from the synergistic effects of metal ions and the unique yolk-shell structure, MxCo3-xO4 YSP displays good OER catalytic activity in alkaline media. Impressively, ZnxCo3-xO4 YSP shows a comparable overpotential of 337 mV at 10 mA cm-2 to commercial RuO2 and exhibits superior long-term durability. The high activity and good stability reveals its promising application.

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Ceria (CeO2) is an exciting alternative noble metal catalyst, because it has ability to release and absorb oxygen in the redox system, and function as an oxygen buffer. In this study, heterostructured catalysts consisting of CeO2/Y2O3 nanocomposites were successfully synthesized by hydrothermal method in the presence of sodium hydroxide as a reducing agent from cerium nitrate and yttrium nitrate as a precursor which was then evaluated for its photocatalytic activity in the degradation of Rhodamine B (RhB) synthetic dye. Scanning electron microscopy (SEM) imparts the surface morphology and size of the prepared sample. Elemental compositions and the purity of the nanoparticles are proved by energy dispersive X-ray Spectroscopy (EDX). CeO2/Y2O3 nanoparticles were made up of CeO and YO bonds which are confirmed by Fourier transform infrared spectroscopy (FTIR). Synthesis temperature and pressure, during hydrothermal reactions, plays a critical role in controlling the shape, size, oxygen vacancy concentration, and low temperature reducibility in CeO2 based nanocomposites. The lattice constants and oxygen vacancy concentrations of ceria nanoparticles also depend upon the concentration of hydroxide ion which leads to better morphology at low temperature and pressure. Hydrogenation of p-nitrophenol to p-aminophenol with a reducing agent is conveniently carried out in aqueous medium by using this binary metal oxide catalyst. Further, the photocatalytic performance of the synthesized nanoparticles was monitored by photocatalytic degradation of Rhodamine B synthetic dye under UV light irradiation. To get maximum photocatalytic degradation (PCD) efficiency, we have used H2O2 for the generation of excess reactive oxygen species (ROS). In addition, the antibacterial activity of nanoparticles against bacteria was also examined. The observed antibacterial activity results are comparable with the results obtained using the standard antibiotic.

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NiCo2O4 microrods with open structures are successfully synthesized using a solvothermal method. Compared with those of dense microspheres, the one-dimensional (1D) porous microrods show much higher capacities and stability for both Li- and Na-ion batteries due to the 1D open structure facilitating fast ion transport and buffering volumetric change during charge/discharge. This work demonstrates that the electrochemical performance of NiCo2O4 is highly dependent on morphologies of the active material.