Facile Co-precipitation Method Research Articles

Facile synthesis of oxygen vacancy-rich ZnxCu1-xFe2O4 nano-catalyst to activate peroxydisulfate for the efficient degradation of tetracycline

Introduction of oxygen vacancies (OVs) into the heterogeneous catalysts is an efficient method to improve their catalytic activity for persulfate activation. The OVs-rich ZnxCu1-xFe2O4 nano-catalysts were synthesized by a facile co-precipitation method and analyzed using various characterization techniques (XRD, FE-SEM, EDS, BET surface area and XPS). OVs-rich ZnxCu1-xFe2O4 nano-catalysts exhibited a significantly higher catalytic activity for the removal of tetracycline (TC) by activating peroxydisulfate (PDS) than ZnFe2O4 and CuFe2O4 nano-catalyst. TC degradation efficiency in different ZnxCu1-xFe2O4/PDS systems demonstrated that Zn0.6Cu0.4Fe2O4 showed the best catalytic performance due to its highest OVs content, largest specific surface area and pore volume, and 90.09% of TC (20 mg/L) was degraded by Zn0.6Cu0.4Fe2O4 with PDS after 60 min. Cu in-situ introduction can increase the amount of OVs in ZnFe2O4 and affect the cross-occupancy of Zn and Fe, thus promoting the generation of the reactive oxygen species (ROS) in PDS-activated process; moreover, doped Cu can also act as an activation site for PDS and boost the formation of active Fe(Ⅱ). Mechanism study showed that all of ROS (1O2, O2•−, SO4•− and •OH) generated in ZnxCu1-xFe2O4/PDS system simultaneously engaged in TC elimination, and 1O2 played the main role. The probable TC degradation pathways in Zn0.6Cu0.4Fe2O4/PDS system were proposed. The practical application potential of magnetic Zn0.6Cu0.4Fe2O4 nano-catalyst in the treatment of TC-contaminated wastewater was assessed by investigating the reusability of Zn0.6Cu0.4Fe2O4, the removal of TC in real water matrix and the toxicity of TC degradation intermediates.

Facile green synthesis of novel iron asparate (Fe-LAA) MOF for adsorptive mitigation of lead (Pb) from water

A newly reported metal organic framework (MOF), designated as Fe-LAA, was successfully synthesized through a one-step facile and green co-precipitation method. Subsequently, Fe-LAA showed effective adsorptive ability to remove the highly toxic inorganic lead (Pb2+) ions from water. The developed MOF with amine functionalization showed enhanced surface properties which were explored in detail employing various standard analytical techniques, namely, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, energy dispersive X-ray, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy and zeta potential analysis. The enhanced pore volume (vp = 0.24 cm3/g) and specific surface area (SBET > 250 m2/g) of the developed MOF compared to the non-modified structural counterpart, MIL88A (SBET: 91 m2/g, vp = 0.13 cm3/g), was successfully illustrated. The maximum Langmuir Pb uptake capacity was determined as 508.2 mg/g at 25 °C. An established mass transfer model, premised on pore-diffusion and adsorption, was utilized to analyze the adsorption kinetics and estimate the optimum effective pore diffusivity (Dp) as well as the mass transfer coefficient (kf). Furthermore, the convective and diffusive time scales (τc and τd) were evaluated to explain the transport characteristics of the solute contaminant. The adsorbent proved to be selective and reusable (over multiple cycles). The significant role of Pb groups in the MOF structure in maintaining strong electronic interaction with lead moieties was reported. Overall, the present study showcases the development and application of novel Fe-LAA MOF as an effective adsorbent for the treatment of Pb in contaminated aqueous medium.

Unleashing the Full Potential of Electrochromic Heterostructured Nickel-Cobalt Phosphate for Optically Active High-Performance Asymmetric Quasi-Solid-State Supercapacitor Devices.

The rational design of hybrid systems that combine capacitor and battery merits is crucial to enable the fabrication of high energy and power density devices. However, the development of such systems remains a significant barrier to overcome. Herein, we report the design of a Ni-Co phosphate (Ni3-xCox(PO4)2·8H2O) nanoplatelet-based system via a facile coprecipitation method at ambient conditions. The nanoplatelets exhibit multicomponent synergy, exceptional charge storage capabilities, rich redox active sites (ameliorating the redox reaction activity), and high ionic diffusion rate/electron transfer kinetics. The designed Ni3-xCox(PO4)2·8H2O offered a respectable gravimetric specific capacity and marvelous capability rate (966 and 595 C g-1 at 1 and 15 A g-1) over the Ni3(PO4)2·8H2O (327.3 C g-1) and Co3(PO4)2·8H2O (68 C g-1) counterparts. Additionally, the nanoplatelets showed enhanced photoactive storage performance with a 9.7% increase in the recorded photocurrent density. Upon integration of Ni3-xCox(PO4)2·8H2O as a positive pole and commercial activated carbon as a negative pole, the constructed hybrid supercapacitor device with PVA@KOH quasi-gel electrolyte exhibits great energy and power densities of 77.7 Wh kg-1 and 15998.54 W kg-1 with remarkable cycling stability of 6000 charging/discharging cycles and prominent Coulombic efficiency of 100%. Interestingly, two assembled devices are capable of glowing a red LED bulb for nearly 180 s. This research paves the way to design and fabricate electroactive species via a facile approach for boosting the design of a plethora of supercapattery devices.

Improving low-temperature NH3-SCR denitration activity and resistance to H2O and SO2 over Nb-modified NbaSn0.3CeOx catalysts by enhancing acidity to compensate for its weak oxidation ability

In this paper, a series of Nb-modified NbaSn0.3CeOx (a = 0.2, 0.4, 0.5) catalysts for denitrification were prepared using a facile co-precipitation method. In order to explore the various individual properties of the samples, the catalysts were characterized by XRD, Raman, N2 adsorption and desorption, TEM, NH3-TPD, H2-TPR, XPS and in-situ DRIFTS tests to understand the influences of the Nb introduction on the NH3-SCR reaction. Among these catalysts, the Nb0.4Sn0.3CeOx catalyst exhibit excellent NH3-SCR performance in the temperature range of 155–450 °C with more than 90 % NO conversion, 100 % N2 selectivity, and possess good resistance to H2O and SO2. Compared with the Sn0.3CeOx catalyst, we believe that the improvement of the low-temperature NH3-SCR performance of the Nb0.4Sn0.3CeOx catalysts is mainly due to the change in the amount of acid, special for the increase in B acid content, which compensates for the effect of the weaken oxidizing ability on the low-temperature activity. Beyond that, the good H2O and SO2 resistance at low temperature after the introduction of Nb into Nb0.4Sn0.3CeOx catalysts was analyzed by using in-situ DRIFTS characterization in detail, and the results indicate that the incorporation of Nb can inhibit the oxidation of SO2 to form sulfate on the catalysts, and prevent the competing adsorption of H2O and NOx, but the adsorption of NH3 is not affected. This work proves that the acidity regulation can improve low-temperature SCR activity by the synergistic effect between oxidation capacity and acidity.

Defect control and optical performance of yttrium orthovanadate nanocrystals via a facile pH-sensitive synthesis

Nanocrystalline YVO4 powders have been synthesized via a facile co-precipitation method, which has been investigated over the wide pH range from 4 to 13. XRD patterns indicated that the phase structure purity of the precipitation is influenced by the pH value. The reaction mechanism of YVO4 crystal was suggested to illustrate the development stages beginning with precipitates to form impure amorphous phase structures such as amorphous yttrium polyvanadate and hydrous Y(OH)3. SEM and TEM techniques were performed to observe the changes of the morphology and size by adjusting the pH conditions after YVO4 nanocrystals were sintered under ambient conditions at 600 °C for 2 h. Luminescence properties showed that the self-activated emission of YVO4 matrix material shows an obvious peak at 486 nm in the 400–650 nm wavelength range, attributing to the charge transfer in the vanadate groups. With decreasing the pH value, the diffuse reflectance spectra of YVO4 nanocrystals demonstrated that the energy gap Eg showed a red-shift trend mainly ascribed to the oxygen vacancies. Moreover, the luminescence emission intensity of YVO4 nanocrystals increases obviously after sintering treatment, which can be explained by the sintering-induced grain growth and improved surface band bending due to the dehydration or the removal of carbonate species. The findings of this study could provide new insights into the understanding of the reaction mechanism of YVO4 crystal with variable optical band gap and offer an opportunity for realizing tunable optical performance by defect structure regulation for laser and optoelectronics applications.

Green Synthetic Approaches of 2-Hydrazonothiazol-4(5H)-ones Using Sustainable Barium Oxide-Chitosan Nanocomposite Catalyst.

The diverse applications of metal oxide-biopolymer matrix as a nanocomposite heterogenous catalyst have caused many researches to scrutinize the potential of this framework. In this study, a novel hybrid barium oxide-chitosan nanocomposite was synthesized through a facile and cost-effective co-precipitation method by doping barium oxide nanoparticles within the chitosan matrix at a weight percentage of 20 wt.% BaO-chitosan. A thin film of the novel hybrid material was produced by casting the nanocomposite solution in a petri dish. Several instrumental methods, including Fourier-transform infrared (FTIR), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), were used to analyze and characterize the structure of the BaO-CS nanocomposite. The chemical interaction with barium oxide molecules resulted in a noticeable displacement of the most significant chitosan-specific peaks in the FTIR spectra. When the surface morphology of SEM graphs was analyzed, a dramatic morphological change in the chitosan surface was also discovered; this morphological change can be attributed to the surface adsorption of BaO molecules. Additionally, the patterns of the XRD demonstrated that the crystallinity of the material, chitosan, appears to be enhanced upon interaction with barium oxide molecules with the active sites, OH and NH2 groups, along the chitosan backbone. The prepared BaO-CS nanocomposite can be used successfully as an effective heterogenous recyclable catalyst for the reaction of N,N'-(alkane-diyl)bis(2-chloroacetamide) with 2-(arylidinehydrazine)-1-carbothioamide as a novel synthetic approach to prepare 2-hydrazonothiazol-4(5H)-ones. This new method provides a number of benefits, including quick and permissive reaction conditions, better reaction yields, and sustainable catalysts for multiple uses.

Photodegradation of antibacterial cefotaxime using Mn doped ZnO nanosphere

Elimination of pharmaceutical waste is essential for aquatic system preservation. In this report, the ZnO and Mn-ZnO nanospheres (MZNs) were effectively synthesized via facile co-precipitation method with different Mn doping concentrations as catalyst for photodegradation of cefotaxime. The structure features of the synthesized MZNs were successfully investigated. The obtained data were confirmed the successful fabrication of nanosphere ZnO and MZNs. The designed MZNs with various Mn concentrations were utilized in photodegradation of cefotaxime under optimum conditions. The photodegradation parameters such as antibiotic initial concentrations, catalyst dosage, and medium pH were carried out under UV irradiation. The superior photocatalytic activity was revealed when the MZNs molar ratio is 0.75 mol.%. The results show that the degradation efficiency of cefotaxime was 99% within 2 h at operating condition (initial concentration 30 mg/L, catalyst amount 0.5 g/ L and pH 9). The photodegradation mechanism of antibacterial cefotaxime drug in water is based on superoxide radicals which are considered the main reactive species. The developed MZNs exhibit high stability for removal of cefotaxime that reached to 98% after four times recycling. The MZNs demonstrated a simple and effective model for photocatalytic degradation of pharmaceutical waste.

Effect of particle size on electrical impedance, ac conductivity and dielectric properties of ZnSnO3 nanomaterial

In this work, we have reported the electrical impedance, frequency dependent ac conductivity and dielectric properties of zinc stannate (ZnSnO3) nanoparticles synthesized by facile co-precipitation method followed by ball milling for different time span to control particle size. Particle size shows decreasing nature upto a certain span of milling time (2 h) followed by an increase and opposite trend is reflected in band gap. Complex impedance analysis depicts presence of non-Debye type or multiple relaxations and depressed semicircles due to grain and grain boundary. Frequency dependent electrical conductivity analysis shows highest conductivity for two hour milled sample followed by a decrease beyond this. Both real and imaginary component of dielectric constant is also maximum for two hour milled sample.

Optimization of LDO-Pectin Synthesis Conditions for the Removal of Metals from Wastewater: A Comparison of Response Surface Methods and Taguchi Approaches.

With the continuous growth of industrialization, the presence of heavy metals (HMs) in the environment has become a critical issue, necessitating cost-effective and efficient techniques for their removal. The present study aimed to determine the optimal preparation conditions for synthesizing pectin (PC) as a polymer sorbent, combined with Magnesium (Mg) Aluminum (Al) layered double oxides (LDOs), using a fast and facile co-precipitation method. Both the response surface method (RSM) and the Taguchi method were employed to optimize the influence of key independent variables, including the molar ratio of cations Mg:Al, the ratio of pectin to LDO, and the temperature for removing multiple elements from wastewater. The results indicated that RSM is more accurate and examines more interactions, while Taguchi reduces the number of tests and is more economical than RSM. However, both statistical methods showed good potential for predicting the adsorption capacity (Qe) of HMs. The optimal preparation conditions were identified as a molar ratio of 3:1, a ratio of pectin to LDO of 7% w/w, and a temperature of approximately 600 °C. In conclusion, the application of RSM and Taguchi approaches was found to be feasible and effective in optimizing the preparation conditions of modified LDO, which can be utilized as a potential adsorbent for removing multiple elements from wastewater.

Nb2O5/BiOCl composite as a visible-light-active photocatalyst for the removal of RhB dye and photoelectrochemical studies

In this work, BiOCl, 0.5%, 1%, and 5% Nb2O5/BiOCl (NBO/BCl) composite were prepared by a facile co-precipitation method. The synthesized materials were characterized using various characterization techniques such as XRD, FTIR, Raman, UV–Vis DRS, PL, BET, and TEM. The XRD confirms the formation of NBO/BCl composite with no impurities detected. The FT-IR results revealed the successful formation of the NBO/BCl composite, where both functional groups belonging to BiOCl and NBO/BCl were present. The TEM showed that BiOCl and 1% NBO/BCl have irregular nanoplate-like morphology with an average thickness of 22 and 18 nm, respectively. The photocatalytic degradation performance of the BiOCl and NBO/BCl composites was evaluated by degrading Rhodamine B (RhB) dye under visible light irradiation. Among all of the photocatalysts, 1% NBO/BCl showed the highest photocatalytic activity in which it degraded 96.7% of RhB dye in 120 min under visible light irradiation. Furthermore, the photoelectrochemical response of BiOCl and NBO/BCl composites was investigated by linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques. The LSV and EIS analysis of NBO/BCl showed enhanced response when exposed to visible light compared to dark conditions. The significant improvement in the photocatalytic and photoelectrochemical performance of NBO/BCl composite was attributed to the synergistic effects of the NBO/BCl which enhanced light absorption abilities and charge carrier transfer making it easier for charge separation by lowering the recombination rate.

Fabrication of 1.6 V asymmetric supercapacitor in an aqueous electrolyte using a CuO-SnO2 composite and activated carbon electrodes

This work reported the successful preparation of the CuO and SnO2 by the facile co-precipitation method for energy storage applications, especially for supercapacitors (SCs). Subsequently, a CuO-SnO2 composite was further prepared to enhance the composites electrochemical properties. The detailed research survey showed that the combination of these two typical pseudocapacitive metal oxides reasonably enhances their structural integrity, and electronic conductivity, resulting in an optimized electrochemical property. According to the electrochemical studies, an exceptional 246 C/g capacitance is revealed by the CuO-SnO2 composite than 162 C/g (SnO2) and 89 C/g (CuO) exhibiting a synergistic effect in the composite between Sn and Cu-based oxides. A high specific energy of 35.3 Wh/kg with a maximal specific power of 4000 W/kg was obtained by assembling a hybrid asymmetric SC (HASC) with activated carbon (AC), symbolized as CuO-SnO2||AC, that yields a high voltage of 1.6 V. Nevertheless, 88.7 % retention in capacitance was revealed after 5000 cycles taken at a the discharge current of 15 A/g, proving the great durability of the CuO-SnO2||AC HASC. From all these exciting findings, SnO2 composite with CuO can be a potential and a viable choice for SCs and other energy storage gadgets.

Structural, optical and thermoelectric properties of (Al and Zn) doped Co9S8-NPs synthesized via co-precipitation method

In the previous decade nanostructure materials have emerged as the necessary ingredient in electronic application and enhancement of device performance. Cobalt sulfide is one such transition metal sulfide which has provoked a lot of interest in the field of research. The present study was related to pure, (Al and Zn) doped cobalt sulfide NPs have been fabricated using facile co-precipitation method. The cubic structure has conformed to XRD analysis and crystallite size of pure and doped Co9S8 NPs in the range of 11 to 29 nm and with W-H method varies from 29 to 51 nm. The SEM micrograph shows that the agglomeration of the particles in the form of clusters. To conform the vibrational modes of (Al and Zn) doped Co9S8-NPs was done with Raman spectroscopy analysis. The absorbance of prepared materials was investigated with UV–VIS and it was also observed that the band gap decreased from 3.6 to 1.94 eV with doping agents. In case of IV analysis shows that the resistivity decreased and conductivity increased of Al and Zn doped Co9S8 NPs. Furthermore, the sharp increase in potential difference at lower temperature indicates that the doped material is an excellent thermoelectric material for energy storage devices.

Visible light assisted photocatalytic degradation of methylene blue using iodine doped Fe3O4-GO composite

Environmental contamination and wastewater discharge from industrial activities are global issues that must be addressed immediately. The uncontrolled discharge of dangerous organic compounds constitutes a significant environmental risk. To solve this issue, heterogeneous photocatalysis with semiconductor metal oxides has appeared as an environmentally benign method for wastewater treatment. Our research aims to create a new iodine-doped magnetic graphene oxide nanocomposite and test its ability to break down the refractory methylene blue dye by photocatalytic techniques using sunlight. The I-Fe3O4-GO composite was synthesized using a facile ultrasonication-assisted co-precipitation method. Several physiochemical techniques were employed for detailed characterization, including SEM-EDX, XRD, FTIR, UV-Vis DRS, and Raman spectroscopy. The band gap value of 2.6 eV was measured using a tauc plot. The I-Fe3O4-GO nanocomposite showed 95% methylene blue degradation under sunlight in about an hour. The improved catalytic efficiency of the synthesized photocatalyst was attained at pH 8, with an I-FeGO dose of 50 mg/100 mL and an oxidant dose of 14 mM. The photocatalyst displayed exceptional photostability after five consecutive reusability cycles. Response surface methodology was the statistical tool for evaluating several interacting parameters for optimizing dye degradation.

Sunlight driven photocatalytic degradation of RhB dye using composite of bismuth oxy-bromide kaolinite BiOBr@Kaol: Experimental and molecular dynamic simulation studies

This study reported the synthesis of a new eco-friendly photocatalyst nanocomposite based on kaolinite clay and bismuth oxybromide (BiOBr@Kaolinite) using a facile co-precipitation method in acidic medium. The prepared nanocomposite was characterized using several techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning microscopy electron (SEM), Transmission electron microscope (TEM), Energy-dispersive X-ray spectroscopy (EDX), UV–Vis diffuse reflectance spectra (DRS), and X-ray photoelectron spectroscopy (XPS). These techniques were used to determine the crystal phase, functional groups, morphology, elementary composition, chemical states, optical properties, and bad gap energy of as synthesized, respectively. The characterized materials were then applied for rapid photodegradation of Rhodamine B dye (RhB), indicating its effective use for the degradation of toxic organic pollutants under sunlight irradiation. The photocatalytic activity study showed that RhB dye (10 mg/L) was degraded within 30 min under sunlight irradiation. The degradation mechanism of RhB and the photocatalytic stability study of the nanocomposite BiOBr@0.4Kaol showed that, the high photocatalytic activity could be attributed to the charge transfer from kaolinite to BiOBr nanoparticles, which prevented the rapid recombination of the electron-hole pair induced during the photocatalytic process. Moreover, MD and DFT-D stimulations and adsorption calculations based on Monte Carlo were applied in this study. This study led to the development of an effective and environmentally friendly photocatalyst nanocomposite for the degradation of toxic organic pollutants in wastewater, highlighting its potential application in water treatment and depollution processes.

Ferroelectric Polarization and Iron Substitution Synergistically Boost Electrocatalytic Oxygen Evolution Reaction in Bismuth Oxychloride Nanosheets.

Ferroelectric materials have gained significant interest in various kinds of water splitting, but the study of ferroelectric materials for electrocatalytic water splitting is in its infancy. Ferroelectric materials have spontaneous polarization below their Curie temperature due to dipolar alignment, which results in surface charges. In 2D ferroelectric materials, spontaneous polarization depends on thickness. Herein, we report that thickness-dependent ferroelectric polarization in 2D nanosheets can also accelerate the oxygen evolution reaction (OER) along with the tailored active surface area of exposed crystalline facets, which improves the electrocatalytic activity relatively. Iron-substituted BiOCl nanosheets of varying thickness are fabricated by varying the pH using a facile coprecipitation method. The substituted iron enhances polarization and electrochemical active sites on the surface. The findings in this study show that the exposed (001) facet and higher thickness of the nanosheets have high ferroelectric polarization and, in turn, superior electrocatalytic activity and remarkable stability, requiring low overpotentials (348 mV and 270 mV at 100 mA/cm2 and 10 mA/cm2) in alkaline (1.0 M KOH) electrolyte. As the thickness of the nanosheets is decreased from 140 to 34 nm, the electrocatalytic performance of iron-substituted BiOCl nanosheets starts to reduce due to the lower Coulomb-Coulomb interaction and the increasing depolarization.

Influence of Sn4+ substitution on the ZnO crystal structure and their enhanced fibre optic gas sensing and photocatalytic degradation performance

An efficient ZnO specimen with Sn4+ substitution was synthesized through facile co-precipitation method, and the specimens were characterized well with sophisticated instruments. The Sn4+ substituent performed a key function in narrowing the band gap and inhibiting the rate of photogenerated electro-hole recombination. The obtained 5% Sn4+ doped ZnO spcimen exhibits excellent photocatalytic performance of organic dye degradation, which was obviously superior than other syntheiszed catalysts. Gas sensing properties of bare ZnO and Snsubstituted ZnO were studied using clad modified fiber optic gas sensor. The different concentrations from 0 to 500 ppm of ammonia, methanol and ethanol were used for gas sensing measurement and results showed that the 5% Sn4+ doped ZnO catalyst had the greatest gas-sensing activity on ethanol. The findings of this work revealed that Sn4+ substitution for Zn2+ may provide an alternate strategy to improving ZnO gas sensing and photocatalytic activity.

Activation of peroxymonosulfate by Fe–Mn-modified MWCNTs for selective decontamination: Formation of high-valent metal-oxo species and superoxide anion radicals

The extensive presence of organic micropollutants in complex water matrices requires the development of selective oxidation technologies. In this study, a novel selective oxidation process was developed via the conjunction of FeMn/CNTs with peroxymonosulfate and successfully used to remove micropollutants such as sulfamethoxazole (SMX) and bisphenol A from aqueous solutions. FeMn/CNTs were prepared using a facile co-precipitation method, characterized using a series of surface characterization techniques, and then tested for pollutant removal. The results showed that the FeMn/CNTs had much greater reactivity than CNTs, manganese oxide, and iron oxide. The pseudo-first-order rate constant with FeMn/CNTs was more than 2.9–5.7 times that of the other tested materials. The FeMn/CNTs had great reactivity in a wide range of pH values from 3.0 to 9.0, with the best reactivity found at pH values of 5.0 and 7.0. High-valent metal-oxo species such as Fe(IV)O and Mn(IV)O and superoxide anion radicals were determined to be the reactive species and were responsible for the oxidation of SMX. These reactive species were selective; therefore, the overall removal performance of SMX was not obviously influenced by high levels of water components including chloride ions, bicarbonates, and natural organic matters. The results from this study may promote the design and application of selective oxidation technologies for micropollutant abatement.

High mass loading and additive-free prussian blue analogue based flexible electrodes for Na-ion supercapacitors

Supercapacitor electrodes often suffer from the low mass loading of active substances and the unsatisfactory ion/charge transport features due to the use of various additives. Exploring high mass loading and additive-free electrodes is of huge significance to develop advanced supercapacitors with commercial application prospects, which still remains challenging. Herein, high mass loading CoFe-prussian blue analogue (CoFe-PBA) electrodes are developed by a facile co-precipitation method using activated carbon cloth (ACC) as the flexible substrate. The homogeneous nanocube structure, large specific surface area (143.9 m2 g−1) and appropriate pore size distribution (3.4 nm) of the CoFe-PBA endow the as-prepared CoFe-PBA/ACC electrodes with low resistance and appealing ion diffusion characteristics. Typically, the high areal capacitance (1155.0 mF cm−2 at 0.5 mA cm−2) is obtained for high mass loading CoFe-PBA/ACC electrodes (9.7 mg cm−2). Furthermore, symmetrical flexible supercapacitors (FSCs) are constructed using CoFe-PBA/ACC electrodes and Na2SO4/polyving alcohol (Na2SO4/PVA) gel electrolyte, achieving superior stability (85.6% capacitance retention after 5,000 cycles), maximum energy density of 33.8 μWh cm−2 at 200.0 μW cm−2 and promising mechanical flexibility. This work is expected to offer inspirations for the development of high mass loading and additive-free electrodes for FSCs.

Photo-sensitive CuS/NiO heterostructure electrocatalysts for energy-saving hydrogen evolution reaction at all pH conditions

Heterostructures based on transition metal chalcogenides/oxides have gained significant interest in the application of electrochemical hydrogen evolution reaction (HER) due to their distinct characteristics and excellent electrocatalytic activity. Herein, we developed an earth-abundant, low-cost, and light-sensitive CuS/NiO (CSNO) heterostructure electrocatalyst via a facile co-precipitation method and fabricated it on silver-modified conducting cellulose paper for HER. Under all pH level, the performance of the visible light-sensitive HER catalyst has been examined. With the illumination of light, HER performance at all pH, which conserves energy has been seen. In basic media, the value of overpotential was improved to −290 mV vs RHE at 20 mA/cm2 under light-illuminating conditions. Similarly, with light illumination, the overpotential of the CSNO10/Ag- modified paper is reduced to −363 mV and −312 mV vs RHE in an acidic and in a near-neutral medium, respectively. In addition to that, the values of the Tafel slopes and charge-transfer resistance also decreased indicating relatively faster HER kinetics in the presence of light at all pH levels. Also, The CSNO10 electrode exhibits stability of more than 24 h in 1 M PBS with an overpotential of −368 mV vs RHE at 20 mA/cm2. The overall performance of the CuS/NiO heterostructure is a good sign to be explored it as a low-cost and efficient electrocatalyst for the large-scale production of green hydrogen (H2).

Highly-impressive performances of novel NiCo2O4/Bi2O3/Ag2ZrO3 nanocomposites in photocatalysis system, removal pathway, toxicity estimation, and antibacterial activities

BackgroundNowadays, drugs have been developed widely for the remediation of different microbial diseases. However, the presence of these compounds have influence on the water bodies. Thereupon, the preparation of inexpensive and efficient catalysts for the antibiotics degradation is important for the treatment of toxic contaminant in water. MethodsThe ternary NiCo2O4-Bi2O3-Ag2ZrO3 nanocomposite has been presented through a facile co-precipitation methods. The as-prepared nanocomposites was studied for the decomposition of metronidazole (MTN) under the visible light, and characterized by different analysis such as TEM, UV-vis, XPS, SEM, FT-IR, EIS, ESR, BET, and PL techniques. Significant findingsThe determined band gap values of Ag2ZrO3, Bi2O3, NiCo2O4 and NiCo2O4-Bi2O3-Ag2ZrO3 nanocomposites were 2.67, 2.45, 2.18 and 1.92 eV, respectively. The degradation efficiency of NiCo2O4-Bi2O3-Ag2ZrO3 under visible light displays the 100.0% decomposition attained in 80 min. The important parameters such as neutral pH, 4.0 g/L of catalyst dosage, and 5 mg/L of MTN concentration were found to be favorable for this reaction. The great recyclability attributes of the prepared catalyst were discerned after five successive cycles. The toxicity of the degraded MTN products were harmless and non-toxic. The scavenging test revealed that ·OH and ·O2− were the important radicals in the degradation of MTN by NiCo2O4-Bi2O3-Ag2ZrO3. The fabricated NiCo2O4-Bi2O3-Ag2ZrO3 was also investigated for the antimicrobial activity.