Sonochemical synthesis of Co2SnO4 nanocubes for supercapacitor applications

Chemically sprayed pristine and Cd 2+ incorporated Co2SnO4 thin films for low ppm level enhanced chemi - resistive behaviour towards dimethylamine detection at room temperature

The surge in hazardous volatile organic liquid emissions driven by the rapid growth of the manufacturing industry has compelled a rising demand for gas sensors, which exhibit remarkable sensitivity, selectivity, and room temperature operation. Ternary metal oxide spinel has indeed garnered significant attention in chemi-resistive gas sensors due to their large reactive surface area, physicochemical, and other unique properties. In this work, we have studied chemically sprayed pristine and Cd 2+ incorporated Co2SnO4 thin film as a sensing layer under room temperature (300 K) conditions. The 5 wt% Cd 2+ incorporated Co2SnO4 films unveiled a high sensor response to dimethylamine (DMA) gas (S = Igas/Iair = 6153 at 1 ppm), which was boosted by 8.89-fold times compared to pristine Co2SnO4 film, due to the large reactive surface area and enhanced defective oxygen vacancies. It has superior selectivity towards DMA gas, good response time (154 s) / recovery time (90 s), superior pro-longevity (S = 6138) after 60 days, stable repeatability (7 cycles), excellent cross-selectivity, and relative humid resistance at 300 K. This research work provides insights on Cd 2+ incorporated Co2SnO4 thin films and their feasibility in real-time gas sensing devices.

In situ or Ex situ Synthesis for Electrochemical Detection of Hydrogen Peroxide-An Evaluation of Co2SnO4/RGO Nanohybrids

Nowadays, there is no doubt about the high electrocatalytic efficiency that is obtained when using hybrid materials between carbonaceous nanomaterials and transition metal oxides. However, the method to prepare them may involve differences in the observed analytical responses, making it necessary to evaluate them for each new material. The goal of this work was to obtain for the first time Co₂SnO₄ (CSO)/RGO nanohybrids via in situ and ex situ methods and to evaluate their performance in the amperometric detection of hydrogen peroxide. The electroanalytical response was evaluated in NaOH pH 12 solution using detection potentials of -0.400 V or 0.300 V for the reduction or oxidation of H₂O₂. The results show that for CSO there were no differences between the nanohybrids either by oxidation or by reduction, unlike what we previously observed with cobalt titanate hybrids, in which the in situ nanohybrid clearly had the best performance. On the other hand, no influence in the study of interferents and more stable signals were obtained when the reduction mode was used. In conclusion, for detecting hydrogen peroxide, any of the nanohybrids studied, i.e., in situ or ex situ, are suitable to be used, and more efficiency is obtained using the reduction mode.

Rational construction of porous marigold flower-like nickel molybdenum phosphates via ion exchange for high-performance long-lasting hybrid supercapacitors

The assembled hybrid supercapacitor device using the urea-based nickel molybdenum phosphate nanopetals embedded microspheres electrode exhibits outstanding long-term cycling stability, demonstrating its practical applications.

Sustainable architecting of Co2SnO4/CE-BN-based electrochemical platform for highly selective and ultrasensitive detection of 2-nitroaniline in life samples

A novel binary heterogeneous electrocatalyst, Co2SnO4, decorated on chemically exfoliated boron nitride sheets (CE-BN) with an exceptional capacity to detect electrochemical properties has been prepared by the simple hydrothermal method. The structural, surface morphology and electrochemical characteristics of Co2SnO4/CE-BN were characterized using a range of physicochemical and electrochemical techniques. Various voltammetric approaches were used to observe the analytical behaviour and applications of Co2SnO4/CE-BN/GCE for the determination of 2-nitroaniline (2-NA). The whole experiment is operated in the potential range from 0 to - 1.0 V vs Ag/AgCl (sat. KCl). The impact of operational factors on the peak current of 2-NA was investigated, including the pH, sample concentration, modifier amount and scan speed. With an estimated differential pulse voltammetry detection limit of 0.0371 µM and excellent sensitivity of 1,35 µA µM-1 cm-2, the produced sensor, Co2SnO4/CE-BN/GCE, revealed high electrocatalytic activity (DPV). The system is more practical and sustainable due to its repeatability, stability and reproducibility with respect to the results achieved for detection of 2-NA. The synthesized Co2SnO4/CE-BN-modified sensor may thus be a likely choice for the detection of 2-NA in actual water sample analysis.

Layered Porous Graphitic Carbon Nitride Stabilized Effective Co2SnO4 Inverse Spinel as a Bifunctional Electrocatalyst for Overall Water Splitting

Developing an efficient, low-cost, and non-noble metal oxide-based nanohybrid material for overall water splitting is a highly desirable approach to promote clean energy harnessing and to minimize environmental issues. Accordingly, we proposed an interfacial engineering approach to construct layered porous graphitic carbon nitride (g-C₃N₄)-stabilized Co₂SnO₄ inverse spinel nanohybrid materials as highly active bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline medium. Here, a Co₂SnO₄/g-C₃N₄ nanohybrid with a layered porous g-C₃N₄ stabilized cubelike inverse spinel has been synthesized with an enhanced surface area via a simple one-pot hydrothermal method. Besides, detailed structural and morphological characterizations were carried out using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared (FT-IR), and Brunauer-Emmett-Teller (BET) analysis. Briefly, XPS analysis has revealed the existence of a strong coupling bond at the interface between a definite proportion of g-C₃N₄ nanosheets and the inverse spinel, which act as an electron transport channel to explore the exceptional performances for HER and OER. Compared to the Co₂SnO₄ inverse spinel lattice or g-C₃N₄ nanosheets, the prepared Co₂SnO₄/g-C₃N₄ nanohybrid-loaded 316 SSL mesh electrode showed excellent and stable electrocatalytic performances with very low overpotentials of 41 mV for HER and 260 mV for OER to reach the current density of 10 mA cm^-2. To understand the electrocatalytic phenomena, the faradic efficiency was calculated for the prepared bifunctional electrocatalyst as 96%, which effectively would favor water electrolysis. Accordingly, the Co₂SnO₄/g-C₃N₄ nanohybrid-loaded electrodes were constructed, and the minimum cell voltage was found to be 1.52 V to reach the current density of 10 mA cm^-2, which is comparable to the standard RuO₂∥Pt/C in two-electrode systems. Thus, the developed nanohybrid-based electrocatalyst could be an alternative to noble metal-centered systems for highly efficient overall water splitting.

Durable and eco-friendly peroxymonosulfate activation over cobalt/tin oxides-based heterostructures for antibiotics removal: Insight to mechanism, degradation pathway

Potential leaching of Co ions could decrease the catalytic activity and cause secondary pollution of water, thereby threatening ecological safety and human health. In response, the in-situ generation of well-dispersed Co₂SnO₄ and SnO₂ with fine interfacial feature was constructed for PMS activation toward efficient tetracycline degradation and lower cobalt ion leaching feature. The synergistic effect of Co₂SnO₄ and SnO₂ endowed Co₂SnO₄-SnO₂ an outstanding catalytic performance for tetracycline degradation in alkaline condition. Meanwhile, the catalysts can effectively degrade the quinolones, dyes and mixture pollutant solution. The excellent performance can attributed to the in-situ introduction of SnO₂, which stabilizes the microstructure and provides an effective electronic pathway to enhance the activity of Co₂SnO₄ in the Co₂SnO₄-SnO₂. In optimized condition, the tetracycline degradation efficiency was enhanced to 94.9% within 20 min and maintained the stability at least four cycles. The degradation rate constant of Co₂SnO₄-SnO₂ was 0.149 min^-1, which was about 1.93, 2.98, 11.5 times higher than of Co₂SnO₄, Co₃O₄ and SnO₂, respectively. Notably, the leaching performance of Co₂SnO₄-SnO₂ was greatly suppressed to be 7.45 ug/L, which was lower than that of Co₂SnO₄ (6.41 mg/L) and Co₃O₄ (1.12 mg/L). Radical quenching and EPR experiments showed that singlet oxygen (¹O₂), rather than hydroxyl active species and sulfate radicals, played a predominating role for PMS activation in the Co₂SnO₄-SnO₂/PMS system. The intermediates and degradation routes for tetracycline degradation were characterized by liquid chromatograph-tandem mass spectrometry. This study expected to provide a novel strategy to construct heterostructural catalysts with lower cobalt ion leaching for the activation of PMS.

In situ synthesis of advantageously united copper stannate nanoparticles for a new high powered supercapacitor electrode

A novel CuNi2O4@SnS@rGO/NF multicomponent hybrid material leads to fast ion/electron transfers at the electrode/electrolyte interface.

Modish Designation of Hollow-Tubular rGO-NiMoO4@Ni-Co-S Hybrid Core-shell Electrodes with Multichannel Superconductive Pathways for High-Performance Asymmetric Supercapacitors

The scrupulous designation of hollow and porous electroactive materials incorporating prolific redox-active polyphase transition-metal oxide decorated with polyphase transition-metal sulfide onto rGO (reduced graphene oxide)-supported conductive substrate has never been an easy task due to the very good coordination affair of sulfur toward transition metals. Herein, cost-effective hydrothermal growth followed by a metal-organic framework (MOF)-mediated sulfidation approach is employed to achieve burl-like Ni-Co-S nanomaterial-integrated hollow and porous NiMoO₄ nanotubes onto rGO-coated Ni foam (rGO-NiMoO₄@Ni-Co-S) as the electrode material for supercapacitors. The open framework of the rGO-Co-MOF template after the etching and sulfidation process not only enables the creation of a tubular structure of NiMoO₄ nanorods but also provides convenient ion-electron pathways to promote rapid faradic reactions for the hybrid composite electrode. Owing to the unique hollow and tubular structure, the as-fabricated rGO-NiMoO₄@Ni-Co-S electrode exhibits a high specific capacity of 318 mA h g^-1 at 1 A g^-1 and remarkable cyclic performance of 88.87% after 10,000 consecutive charge-discharge cycles in an aqueous 2 M KOH electrolyte on a three-electrode configuration. Moreover, the assembled rGO-NiMoO₄@Ni-Co-S//rGO-MDC (MOF-derived carbon) asymmetric supercapacitor device exhibits a satisfactory energy density of 57.24 W h kg^-1 at a power density of 801.8 W kg^-1 with an admirable life span of 90.89% after 10,000 repeated cycles.

Ultrasonic synthesis of α-MnO2 nanorods: An efficient catalytic conversion of refractory pollutant, methylene blue

In this work, uniform α-MnO₂ nanorods were synthesized via a simple hydrothermal followed by ultrasonication method using ultrasonic bath (20 kHz, 100 W) without using any surfactant and template. The crystallographic phases and surface morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transition electron microscopy (TEM) analysis, respectively. Functional group identification and chemical states of α-MnO₂ nanorods were confirmed by Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The as-synthesized uniform nanorods of α-MnO₂ exhibit excellent catalytic conversion of toxic organic contaminant (methylene blue (MB)) in the presence of NaBH₄ as reductant. The α-MnO₂ exhibits excellent stability up to four repeated catalytic cycles with nearly 92% conversion. The kinetic rate constant (k), and turnover frequency (TOF) were 0.736 min^-1 and 0.02 mmol mg^-1 min^-1, respectively. In addition, the fast electron transfer mechanism were investigated and discussed. These results open a new avenue for developing various metal oxide catalysts, which are expected to be very useful catalytic conversions.

Sonochemical synthesis of molybdenum oxide (MoO3) microspheres anchored graphitic carbon nitride (g-C3N4) ultrathin sheets for enhanced electrochemical sensing of Furazolidone

Present strategy introduce the sonochemical synthesis of molybdenum oxide (MoO₃) microspheres anchored graphitic carbon nitride (g-C₃N₄) ultrathin sheets as a novel electrocatalyst for the detection of Furazolidone (FU). TEM results revealed that MoO₃ are microspheres with an average size of 2 µM and the g-C₃N₄ seems like ultrathin sheets. Owing to their peculiar morphological structure, g-C₃N₄/MoO₃ composite modified electrode provided an enriched electroactive surface area (0.3788 cm²) and higher heterogeneous electron transfer kinetics (K°_eff = 4.91×10^-2 cm s^-1) than the other controlled electrodes. It is obviously observed from the voltammetric studies that the proposed sensor based on g-C₃N₄/MoO₃ composite can significantly improve the electrocatalytic efficiency towards the sensing of FU. Due to the excellent synergic effect of g-C₃N₄/MoO₃ composite, can detect the ultra-level FU with a limit of detection of 1.4 nM and a broad dynamic range of 0.01-228 µM, which surpassed the many previously reported FU sensors. Hence, the proposed sensor was successfully applied to sensing the FU in human blood serum, urine and pharmaceutical samples, gained an agreeable recoveries.