Simple Co-precipitation Route Research Articles

Construction of heterojunction superparamagnetic Cd0.5Ag0.5Fe2O4 nanocomposite photocatalyst for simulated textile effluent oxidation

Abstract Significant attempts have been recently made regarding nanomaterials due to their several environmental applications especially in wastewater treatment technologies. Among the available nanoparticles, ferrite based substances are gaining a special interest since their superior characteristics such as their magnetic nature, high adsorption capacity and large specific surface area. In this regard, Cd0.5Ag0.5Fe2O4 was prepared using the green simple co-precipitation route. Then, the sample is characterized via Scanning Electron Microscopy (SEM) that proved the produced material’s surface morphology. The substance is then employed as a catalyst source for Fenton reaction to oxidize textile effluent solution containing Rhodamine B (Rh-B 6G) dye. The oxidation experiment conducted under ultraviolet (UV) light with the ferrite-based Fenton catalyst supplemented with hydrogen peroxide showed an exceptional removal rate of up to 94% removals. Notably, the oxidation system is significantly impacted by the operational variables. The oxidation efficiency of the dye was maximized at pH 3.0 and 50 mg/L and 1600 mg/L for ferrite-based Fenton catalyst and H2O2, respectively. The impacts of the operational factors, i.e. initial pH value, initial dye concentration, catalyst, and H2O2 concentrations were also investigated. This perspective introduces the role of a superparamagnetic material to be a recyclable sustained catalyst.

Efficient Catalytic Synthesis of Glycerol Carbonate Using Optimized Na and K Titanate Nanotubes Catalysts

The synthesis of glycerol carbonate from glycerol has garnered significant research attention because of its wide application in the lithium-ion battery and pharmaceutical industries. This study summarizes the catalytic transformation of glycerol to glycerol carbonate using Na and K titanate nanotubes as catalysts. We report the synthesis of Na and K titanate nanotubes catalyst by a simple co-precipitation route and investigate their catalytic activity in the transesterification of glycerol. The physicochemical properties of the Na and K titanate nanotubes catalyst were successfully studied by CO2-TPD and XRD. The designed catalyst possesses high catalytic efficiency and stability in the transesterification reaction of glycerol. Based on its surface area and basicity, several experiments were performed, and it was observed that under optimized conditions (i.e., 5 wt.% catalyst loading, 5:1 molar ratio of DMC to glycerol, 90 °C, and 90 min), the highest conversion of glycerol was achieved, 92.6% glycerol carbonate. The high thermal stability and recyclability make it an efficient heterogeneous catalyst for the synthesis of glycerol carbonate.

Simultaneous Environmental Waste Management through Deep Dewatering of Alum Sludge Using Waste-Derived Cellulose

To simultaneously solve problems in an eco-friendly manner, introducing a waste residual as a sustainable conditioner to aid alum sludge dewatering is suggested as a cradle-to-cradle form of waste management. In this regard, the superiority of deep dewatering alum sludge with a powdered wood chip composite residual as a novel conditioner was explored, whereby traditional conventional conditioners, i.e., polyelectrolytes and lime, were substituted with powdered wood chips. Initially, Fe3O4 was prepared at the nanoscale using a simple co-precipitation route. Next, wooden waste was chemically and thermally treated to attain cellulosic fine powder. Subsequently, the resultant wood powder and Fe3O4 nanoparticles were mixed at 50 wt % to attain a wood powder augmented with iron, and this conditioner was labeled nano-iron-cellulose (nIC-Conditioner). This material (nIC-Conditioner) was mixed with hydrogen peroxide to represent a dual oxidation and skeleton builder conditioning substance. Characterization of the resultant conditioner was carried out using transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) transmittance spectrum analysis. The feasibility of the experimental results revealed that the moisture content in the sludge cake was lower after conditioning, and the capillary suction time (CST) was reduced to 78% compared to that of raw alum sludge after 5 min of dewatering time. Moreover, the optimal system parameters, including nIC-Conditioner and H2O2 concentrations, as well as the working pH, were optimized, and optimal values were recorded at 1 g/L and 200 mg/L for nIC-Conditioner and H2O2, respectively, with a pH of 6.5. Additionally, scanning electron microscope (SEM) analyses of the sludge prior to and after conditioning were conducted to verify the change in sludge molecules due to this conditioning technique. The results of this study confirm the sustainability of an alum sludge and waste management facility.

Thermal Energy Storage Using Hybrid Nanofluid Phase Change Material (PCM) Based on Waste Sludge Incorp Rated ZnO/α-Fe2O3.

Renewable solar energy storage facilities are attracting scientists' attention since they can overcome the key issues affecting the shortage of energy. A nanofluid phase change material (PCM) is introduced as a new sort of PCM is settled by suspending small proportions of nanoparticles in melting paraffin. ZnO/α-Fe2O3 nanocrystals were prepared by a simple co-precipitation route and ultrasonically dispersed in the paraffin to be a nanofluid-PCM. The behaviors of the ZnO/α-Fe2O3 nanocrystals were verified by X-ray diffraction (XRD) analysis, and the average particle size and the morphology of the nanoparticles were explored by transmission electron microscopy (TEM). For the object of industrial ecology concept, aluminum-based waste derived from water-works plants alum sludge (AS) is dried and augmented with the ZnO/α-Fe2O3 nanocrystals as a source of multimetals such as aluminum to the composite, and it is named AS-ZnO/α-Fe2O3. The melting and freezing cycles were checked to evaluate the PCM at different weight proportions of AS-ZnO/α-Fe2O3 nanocrystals, which confirmed that their presence enhanced the heat transfer rate of paraffin. The nanofluids with AS-ZnO/α-Fe2O3 nanoparticles revealed good stability in melting paraffin. Additionally, the melting and freezing cycles of nanofluid-PCM (PCM- ZnO/α-Fe2O3 nanoparticles) were significantly superior upon supplementing ZnO/α-Fe2O3 nanoparticles. Nanofluid-PCM contained the AS-ZnO/α-Fe2O3 nanocrystals in the range of 0.25, 0.5, 1.0, and 1.5 wt%. The results showed that 1.0 wt% AS-ZnO/α-Fe2O3 nanocrystals contained in the nanofluid-PCM could enhance the performance with 93% with a heat gained reached 47 kJ.

Significant improvement of the electrochemical performance of nanoscale Zinc vanadate as an electrode material for supercapacitors via redox additive electrolytes

Nanostructured Zinc vanadate (Zn3(VO4)2) has been successfully synthesised via a simple and low-cost co-precipitation route. The Zn3(VO4)2 nanoparticles (NPs) possess a specific capacitance of 83.83 F/g at a current density of 1 A/g in 6 M KOH. Remarkably, the working electrode shows an excellent specific capacitance of 869.87 F/g in K3[Fe(CN)6] redox additive electrolytes (RAE). Moreover, the fabricated asymmetric supercapacitor (ASC) achieved 3.626 Wh/kg energy density and 3125 W/kg power density.

Doping of Co3O4–ZrO2 in graphene nanoplatelets for enhanced electrochemical catalytic degradation of phenol

This study presents the synthesis of CO3O4–ZrO2 (CZ) doped Graphene nanoplatelets (GNPs) composite (GNPs-CZ) via simple co-precipitation route and was drop casted on carbon fiber paper (CFP) to fabricate the modified electrochemical sensor (GNPs-CZ/CFP) electrode for sensitive determination of phenol (Ph) in 0.1 M phosphate buffer solution (PBS). The physico-chemical characterization was done by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). GNPs-CZ composite exhibits enhanced electrochemical behavior towards Ph as shown by voltammetric techniques. The enhanced electro-oxidation of Ph was attributed to the joint efficiency of GNPs and CZ. Co3O4 being very surface sensitive to carbonate species; the introduction of ZrO2 to it stabilizes its active sites and enhances the decomposition of carbonate. Electrode fouling is the prime hurdle in electrochemical detection of Ph as the bare electrode gets poisoned due to dimerization of phenol and the oxidation current decreases. This challenge was removed by coating the bare electrode with GNPs-CZ composite. The addition of GNPs effectively improves the surface area, and enhances the electrons transfer rate showing better electrocatalytic response. A higher sensitivity (748 μA mM˗1), appreciable detection limit (74 μM), and wide linear range (20˗400 μM) with good stability are achieved. Thus, the GNPs-CZ/CFP electrode has the potential to be used as Ph electrochemical sensor for pollution control scenario.

Label-Free Detection of Epinephrine Using Flower-like Biomimetic CuS Antioxidant Nanozymes.

A biosensor comprising crystalline CuS nanoparticles (NPs) was synthesized via a one-step simple coprecipitation route without involvement of a surfactant. The powder X-ray diffraction method has been used to evaluate the crystalline nature and different phases consist of the formation of CuS NPs. Mainly hexagonal unit cells consist of the formation of CuS NP unit cells. Most of the surfaces are covered with rhombohedral microparticles with a smooth exterior and surface clustering, examined by SEM images, and the shape of NPs was spherical, having an average size of 23 nm, as confirmed by TEM analysis. This study has focused on the peroxidase-mimicking activity, superoxide dismutase (SOD)-mimicking activity, and chemosensor-based colorimetric determination and detection of epinephrine (EP) neurotransmitters with excellent selectivity. The CuS NPs catalyzed the oxidation of the oxidase substrate 3, 3-5, 5 tetramethyl benzidine (TMB) with the help of supplementary H2O2 that followed Michaelis-Menten kinetics with excellent Km and Vmax values calculated by the Lineweaver-Burk plot. Taking advantage of the drop in absorbance upon introduction of EP for the CuS NPs-TMB/H2O2 system, a colorimetric route has been developed for selective and real-time detection of EP. The sensitivity of the new colorimetric probe was vibrant, having a linear range of 0-16 μM, and achieved a low limit of detection of 457 nM. Moreover, the present nanosystem exhibited appreciable SOD-mimicking activity which could effectively remove O2•- from commercial cigarette smoke, along with it acting as a potential radical scavenger as well. The new nanosystem effectively scavenged •OH, O2.-, and metal chelation which were investigated calorimetrically.

An accelerated route for synthesis of Glycerol carbonate using MgTiO3 perovskite as greener and cheaper catalyst

Synthesis of glycerol carbonate from glycerol has gained major research attention because of its wide application in lithium-ion battery and pharmaceutical companies. Current study summarises the catalytic transformation of glycerol-to-glycerol carbonate using MgTiO3 perovskite catalyst. Here,we have reported the synthesis of MgTiO3 catalyst by simple co-precipitation route and investigated the catalytic activity in transesterification of glycerol. The physico-chemical properties of MgTiO3 catalyst was successfully studied by XRD, SEM-EDX, XPS, Raman spectra, BET-surface area and TGA analysis. The designed catalyst possesses high catalytic efficiency and stability in transesterification reaction of glycerol. Depending upon its surface area and basicity many experiments were performed and observed that under optimized condition i.e., 12 wt.% catalyst loading, 6:1 molar ratio of DMC to glycerol, 90 °C and at 180 min highest conversion of glycerol 93% and 88% selectivity of glycerol carbonate was achieved. The reusability study also revealed that MgTiO3 perovskite is highly efficient and stable catalyst to trans esterify glycerol with 88% selectivity towards glycerol carbonate up to sixth cycle.

Chitosan impregnated with magnetite as a versatile photocatalytic nanocomposite for Synozol Red KHL dye elimination from aqueous effluent

ABSTRACT The combination of marine polysaccharides, chitosan (CS), that is signified as bio-polymeric substance with environmentally benign magnetite (Fe3O4) has led to an ever expanding of its applications. Such modification tends CS to be superparamagnetic photocatalyst and could be recoverable, recyclable and a sustainable material. Herein, Fe3O4 reinforced CS that is so-called Fe3O4@CS nanocomposite was fabricated in different proportions (Fe3O4@CS (2:1), (1:2) and (1:3) using simple co-precipitation route. The characteristics of the prepared samples were investigated to explore their structure and morphology using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometer. Thereafter, the polymer-based photocatalyst was used as a Fenton’s reaction for oxidation of Synozol Red KHL dye in aqueous media. The effects of several operational parameters on the photocatalytic performance are also described. In addition, the catalyst recyclability is achieved to attain its activity after 6th cycles with high removal efficiency. The process optimisation using response surface methodology is conducted and the optimal operational conditions recorded are 465 and 2 mg/L for H2O2 and Fe3O4@CS nanocomposite, respectively at pH 2.0. The dye removal reached to a complete mineralisation (100%) within 30 min of irradiance time. Kinetic data revealed the oxidation system follows the first-order reaction kinetic and the thermodynamic parameters confirmed the reaction is endothermic and non-spontaneous in nature. The reaction confirmed its sustainability since it is applied using solar energy as an economic source with 100% removal within 30 min in the solar reactor.

Frail room temperature ferromagnetism and H2 evolution of ZnS:Er nanoparticles through simple chemical co-precipitation route

Frail room temperature ferromagnetism and H2 evolution of ZnS:Er nanoparticles through simple chemical co-precipitation route

Boosted natural sunlight driven photodegradation of organic dyes using rGO anchored Pr/Cu dual-doped ZnO nanocomposite: Characterization and mechanistic insight

The advancement of sunlight-driven metal oxide semiconductor-based, highly efficient photocatalysts for removing contaminants like dyes from wastewater remained a challenge. In this work, Pr/Cu dual-doped ZnO anchored with different rGO concentrations were synthesized by simple co-precipitation and ultrasonication route. The structural, morphological, and optical characterization of prepared materials was performed with different techniques and employed for degrading diverse kinds of dyes pollutants under natural sunlight illumination. The photodegradation efficiency after 40 min sunlight illumination towards Methyl Orange (MO) was 51.00, 75.00, and 99.76% for ZnPrCuO (S1), ZnPrCuO/rGO (1:1) (S2), and ZnPrCuO/rGO (1:2) (S3), respectively. The results suggested that the introduction of Pr/Cu and rGO significantly boosted the photodegradation ability of ZnO under sunlight. Especially, S3 nanocomposite exhibited the highest photodegradation of safranin-O (SO), Rhodamine-B (RhB), and methylene blue (MB) dyes, having degradation efficiency of 65.50, 91.40, and 99.80%, respectively, in 40 min. The scavenger test results exhibited that •OH and •O2− were the foremost active species in the photodegradation process. Moreover, the reusability experiments and tracing XRD after reusing samples revealed that the S1 catalyst has excellent recyclability (6th cycle). The reduction in energy bandgap and creation of impurity energy level by Pr/Cu doping leads to inhibit carrier pair recombination and effective charge transfer/separation. These findings revealed that Pr/Cu doping and rGO have the potential to enhance the visible light response of ZnO to eliminate dyes pollutants in wastewater with energy saving.

Synthesis and characterization of pyrochlore-type lanthanum cerate nanoparticles: Electrochemical determination of antibiotic drug sulfadiazine in biological and environmental samples

In recent eras, antibiotic drugs are essential for humans and the veterinary health system. However, the improper discarding of their residues are simply contaminating the food products and environmental samples. Here, pyrochlore-type lanthanum cerate nanoparticles (LaCe NPs) were prepared through a simple co-precipitation route and used as effective electrocatalyst for the detection of antibiotic drug sulfadiazine (SDZ). The structural investigations of prepared material were carried out using XRD, FT-IR, XPS, SEM, HR-TEM, and EDX along with Elemental mapping analysis, which confirm the good formation of pyrochlore type LaCe in the form of particle-like morphology with well-crystalline nature. A nanosized LaCe revealed superior electrochemical activity towards SDZ owing to the large surface area, facilitating mass and ionic transport and chemical stability phenomena. The as-prepared LaCe NPs demonstrated an excellent electrochemical performance towards SDZ determination with a low LOD (50 nM), a wide dynamic range of 0.04–1525 μM, and an acceptable sensitivity of 1.92 μA μM−1 cm−2. Furthermore, the LaCe NPs/GCE revealed excellent reproducibility, storage stability, and selectivity parameters. Additionally, the proposed sensor achieves a good SDZ recovery in milk and human urine samples. The results strongly suggest that the rare earth metal oxide of lanthanum cerate is an efficient catalyst for portable detection of SDZ.

Effect of doping of iron on structural, optical and magnetic properties of CeO2 nanoparticles

CeO2, 0.5 Fe/CeO2, 1 % Fe/CeO2, 3 % Fe/CeO2, and 5 % Fe/CeO2 nanoparticles (NPs) were prepared by simple chemical co-precipitation route. The structural, morphological, and compositional analysis of the prepared samples were studied. The pristine CeO2 is diamagnetic whereas doped samples of Fe with CeO2 enhance ferromagnetism in CeO2 and the hysteresis area increases up to 5 mol % of Fe. Hence, to induce a ferromagnetic behaviour in CeO2 NPs,5 mol % of Fe is found to be optimum. The presence of Fe3+ as found from the XPS chemical analysis to acts as an electron acceptor and/or hole donor, facilitating longer charge carrier separation in Fe-doped CeO2.

Structural, optical and morphological investigation of bismuth substituted cerium ferrite: An efficient photocatalyst and dielectric material for various applications

In this work, Bi-doped cerium ferrite Ce1-xBixFeO3 (x = 0.00, 0.01, 0.03, 0.05, 0.07, 0.09) was synthesized via a simple co-precipitation route. The as-synthesized samples were investigated by UV–visible (UV–Vis) spectroscopy, photoluminescence spectroscopy, vibrational Raman and Fourier transform infrared (FTIR) spectroscopies, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) analyses to study the influence of Bi doping on the optical, structural, morphological and textural characteristics of cerium ferrite. Dielectric studies indicated the charge storage potential of Bi-doped cerium ferrites where a considerable increase in dielectric constant was observed in the case of Ce0.93Bi0.07FeO3 (1.29178 × 107) compared to the pristine cerium ferrite (1.97615 × 10−11) at 20 Hz. Moreover, small loss tan value of Ce0.93Bi0.07FeO3 (1.36704) reflected its ability to store charges with minimum current leakage. The prepared samples were also investigated for the photocatalytic degradation of a strong anti-inflammatory drug i.e. diclofenac potassium in aqueous media. The photocatalytic degradation of diclofenac potassium by Ce0.93Bi0.07FeO3 reached 93% of conversion and was the highest value compared to pristine cerium ferrite (73%), following pseudo-first order kinetics with the rate constant of 0.02038 min−1. This enhanced photocatalytic activity could be attributed to the effective suppression of the charge carriers owed to the crystal defects induced by Bi doping leading to the formation of active species responsible for the degradation of diclofenac. This work established the potential applicability of the ferrite-based composites towards photocatalytic removal of pollutants as well as their use in charge storage devices.

Improved toxic NO2 gas sensing response of Cu-doped ZnO thin-film sensors derived by simple co-precipitation route

The application of ZnO nanomaterial in the gas sensing field has been extensively studied. The simple co-precipitation method was used to synthesize 0–4 at.% Cu-doped ZnO (ZC0-ZC4) nanomaterials and the drop-casting method was used to prepare ZC0-ZC4 thin-film sensors. XRD, FESEM and EDX, HRTEM, FTIR, UV–Visible spectroscopy and XPS techniques were used to examine the structural, morphological and spectral properties of pure ZnO and Cu-doped ZnO samples. The prepared ZC0-ZC4 thin-film sensors were investigated at various operating temperatures (120–280 °C) and NO2 gas concentrations (5–100 ppm). The gas sensing study reveals that the 3 at.% Cu-doped ZnO (ZC3) thin-film sensor shows a maximum 326% NO2 gas sensing response at 100 ppm concentration and 200 °C working temperature. The ZC3 sensor has high selectivity for the NO2 gas in the presence of different interfering gases such as Cl2, H2S, SO2 and NO2. The ZC3 sensor showed excellent reproducibility and response/recovery time for the NO2 gas response. The probable NO2 gas sensing mechanism of Cu-doped ZnO sensors is studied and discussed.

Intelligent modelling for the elimination of lanthanides (La3+, Ce3+, Nd3+ and Eu3+) from aqueous solution by magnetic CoFe2O4 and CoFe2O4-GO spinel ferrite nanocomposites

In this research, a novel CoFe2O4-GO (Graphen Oxide) resulting from the combination of high applicable magnetic and organic base materials and synthesized with a simple and fast co-precipitation route was synthesized for the REEs (Rare Earth Elements) extraction. This adsorbent could remove the La3+, Ce3+, Nd3+ and Eu3+ by maximum adsorption capacity of 625, 626, 714.2, 1111.2 mg/g at optimized pH = 6, respectively. A data-driven model was obtained using Group Method of Data Handling (GMDH)-based Neural Network to estimate the adsorption capacity of these LREEs as a function of time, pH, temperature, adsorbent ζ (zeta)- potential, initial concentration of lanthanides ions, and ε which is defined by the physico-chemical properties of lanthanides. The results clearly indicated that the model estimate the experimental values with good deviation (mostly less than 10%) and it can be used for the prediction of the results from other similar researches with less than 25% deviation. The results of sensitivity analysis indicated that the adsorption capacity is more sensitive to pH of the solution, temperature, and ε. Finally, the desorption studies showed an excellent removal efficiency (97%) at least for three adsorption-desorption cycles. These results claimed that the CoFe2O4-GO is a highly efficient adsorbent for the REEs extraction.

Ca19Zn2(PO4)14 Nanoparticles: Synthesis, characterization and its effect on the colonization of Streptococcus mutans on tooth surface

The main cause of tooth decay is the biofilm formation of Streptococcus mutans. This study aimed to investigate the effect of the zinc oxide nanoparticles (ZnO NPs), hydroxyapatite nanoparticles (Ca10(PO4)6(OH)2) (HAP NPs), zinc oxide/hydroxyapatite nanocomposites (ZnO/HAP NCs), and Zn-substituted hydroxyapatite nanoparticles (Ca19Zn2(PO4)14 NPs) on the growth and biofilm formation, bacterial adherence, and the expression of ftf and gtf genes in Streptococcus mutans. The nanostructures were prepared via simple and fast co-precipitation route. Twelve isolates of Streptococcus mutans collected from children with dental caries referred to the dental clinic of Kashan University of Medical Sciences. All S. mutans isolates were susceptible to Ampicillin. The mean MIC for ZnO NPs, HAP NPs, Ca19Zn2(PO4)14, and ZnO/HAP NCs were 118, 260, 70.6, and 994 µg/mL, respectively. All prepared nanostructures significantly reduced biofilm formation at MIC and sub-MIC concentrations (p < 0.01). In biofilm and cell culture treated with nanoparticles, the expression of ftf and gtfC genes decreased. Results were shown that IC50 for the Ca19Zn2(PO4)14 was 8.5, and for non-toxic concentration, was 0.065 µg/mL. The attachment rate to the denture surface and HGF1 cell line treated with the Ca19Zn2(PO4)14 NPs has decreased. The results showed that the Ca19Zn2(PO4)14 NPs has a better effect than the ZnO/HAP NCs. It can therefore be used as a coating on dental surfaces. Investigation of Ca19Zn2(PO4)14 NPs form for covering dental teeth surface recommended in future study.

Architecture and performance of anion-doped Co-free lithium-rich cathode material with nano-micron combined morphology

Co-free cathode materials are gradually attracted wide attention due to the low budget and environmental friendliness, but their application is still prevented by the poor rate performance and cyclic stability. Herein, the Co-free lithium-rich cathode materials (Li1.2Ni0.2Mn0.6O2, LRNMO) with a nano-micron combined morphology is prepared by a simple oxalate co-precipitation route and further modified by an anion doping strategy. It has been found that the F− anion doping can increase the content of Mn4+ in LRNMO, reduce the influence of the Jahn-Teller effect, and further impede the transition from layered phase to spinel phase. As a result, the as-obtained Li1.2Ni0.2Mn0.6O2-xFx (x = 0.04, named as F4-LRNMO) shows an optimal electrochemical performance, for instance, high discharge capacity (243 mAh g−1) with a satisfactory initial coulombic efficiency of 84.37% at 0.1C. Meanwhile, the F4-LRNMO sample also can display high capacity retention of 92.2% after 200 cycles at 1C, and a remarkably high discharge capacity of 151 mAh g−1 with capacity retention of 95.4% after 100 cycles even at high rate of 5C. In consequence, this work can not only ameliorate the defects of poor stability and low initial coulomb efficiency, but also offer a meaningful exploration for the development of Co-free lithium-rich cathode materials with high capacity and high performance-price ratio.

Dye-sensitized solar cell performance and photocatalytic activity enhancement using binary zinc oxide-copper oxide nanocomposites prepared via co-precipitation route

Zinc oxide nanoparticles (ZnO NPs) and binary ZnO–CuO nanocomposites (ZnO–CuO NCs) were prepared through a simple chemical co-precipitation route. The influence of copper (Cu2+) ions concentration (0.03, 0.06, 0.09, and 0.12 M) on optical, morphological, structural, and elemental characteristics of the ZnO–CuO NCs was examined by appropriate characterization techniques. The visible light reactive CuO created absorption shift to red region that minimized band gap of the ZnO–CuO NCs. The concentration of Cu2+ ions produced appreciable impact on size of the ZnO–CuO NCs. The dye-sensitized solar cell (DSSC) constructed using ZnO–CuO NC photoanode with Cu2+ ions concentration of 0.06 M generated a conclusive solar to electrical energy transformation efficiency of 2.56%, which was a 2.2-times greater over the DSSC encompassed pristine photoanode of ZnO NPs. The electrochemical impedance spectroscopy analysis revealed the longer lifetime of the photogenerated electrons and reduction in the charge recombination rate in the ZnO(0.44)–Cu(0.06) NC photoanode based DSSC. Furthermore, the ZnO(0.44)–Cu(0.06) NC disclosed substantial photocatalytic activity towards methylene blue dye degradation that could be chiefly credited to its particles size induced visible light absorption property.

Ethylene glycol assisted MnCO3 electrocatalyst for water oxidation and hydrogen production application

In this research, manganese carbonate nanostructures were prepared employing simple co-precipitation route using ethylene glycol. Rhombohedral phase of MnCO3 nanostructures was determined by X-ray diffraction. MnCO3@15 ml EG electrode exhibited small Tafel slope value and significantly facilitating its OER performance. The fabricated electrode materials of MnCO3 nanostructure exhibited high 257 mA/g current density with low 184 mV overpotential. The prepared electrodes explored excellent OER performance and good stability over 16 h without degradation. Organic additive of ethylene glycol tuning its morphology to favor of OER activity and it enhanced the electrochemical performance of MnCO3 nanomaterial. MnCO3 material was also subjected to photocatalytic hydrogen production. There was no activity noticed in the pure water even after 3 h of experiments. The following factor may enhance the H2 evolution rate. They are introducing hetero-atoms in crystal lattice points, combination with carbon materials such as GO, g-C3N4 etc and composed of heterostructures with some other material such as TMDs, CdS, TiO2 and ZnS etc. Hence, mono metal carbonate of MnCO3 doesn’t show any H2 activity and the fabricated electrode was suitable candidate for oxygen evolution reaction.