Simple Solution Combustion Method Research Articles

Enhancement of photoluminescence of Cd0.95Eu0.05SiO3 phosphor using Na+ and K+ as charge compensators

Despite its high photoluminescence (PL) performance, cadmium silicate (CdSiO 3 ) as a luminescence host has not been comprehensively studied. In this article, we present a simple solution combustion method for the synthesis of Na + and K + co-doped Cd 0.95 Eu 0.05 SiO 3 phosphor. The influence of charge compensators such as Na + and K + on the luminescence performance of Cd 0.95 Eu 0.05 SiO 3 was systematically investigated. X-ray diffraction results confirms that Cd 0.95 Eu 0.05 SiO 3 :Na + and Cd 0.95 Eu 0.05 SiO 3 : K + phosphors are in monoclinic phase and found to increase in the crystallinity as concentration of Na + and K + increases. Scanning electron microscope images exhibit agglomerated particles having nanoscale dimension. PL excitation spectra of Cd 0.95 Eu 0.05 SiO 3 , Cd 0.95 Eu 0.05 SiO 3 :Na + and Cd 0.95 Eu 0.05 SiO 3 :K + phosphors exhibit excitation peaks in the ultra-violet (UV), near-UV and far-UV regions. Very interestingly, the intensity of PL emission was found to increase with increase in the Na + and K + concentrations. The optimum co-dopant concentrations were found to be 7 mol% for both phosphors. The emission intensity of 613 nm peak was enhanced by a factor of 1.78 and 1.66 with Na + and K + co-doping respectively. The enhancement in PL emission has been explained by the mechanism of charge compensation and phosphor crystallinity. The PL results confirms that these phosphors could be potential materials for optoelectronic applications.

Influence of the Amount of Carbon during the Synthesis of LaFe0.8Co0.2O3/Carbon Hybrid Material in Oxygen Evolution Reaction.

The oxygen evolution reaction (OER) and the hydrogen evolution reaction occurred at the anode and cathode, which depends on the electronic structure, morphology, electrochemically active surface area, and charge-transfer resistance of the electrocatalyst. Transition metals like cobalt, nickel, and iron have better OER and oxygen reduction reaction activities. At the same time, transition-metal oxide/carbon hybrid has several applications in electrochemical energy conversion reactions. The rich catalytic site of transition metals and the excellent conductivity of carbon material make these materials as a hopeful electrocatalyst in OER. Carbon-incorporated LaFe0.8Co0.2O3 was prepared by a simple solution combustion method for the development of the best performance of the electrocatalyst. The catalyst can deliver 10 mA/cm2 current density at an overpotential of 410 mV with better catalytic stability. The introduction of carbon material improves the dispersion ability of the catalyst and the electrical conductivity. The Tafel slope and onset potential of the best catalyst are 49.1 mV/dec and 1.55 V, respectively.

Phytochemical mediated synthesis of praseodymium doped beta-eucryptite nanophosphor for ultraviolet stimulated fluorescence based unclonable security applications

Herein, we reported the preparation of orange-red emitting Pr3+ (1–11 mol %) doped beta-eucryptite (LiAlSiO4) nanophosphors via a simple low-temperature solution combustion method. The prepared beta-eucryptite revealed hexagonal crystal structure. The Pr3+doped beta-eucryptitedisplays broad emission peak at 608 nm along with a weak intensive peak at 632 nm ascribed to1D2→3H4and 3P0→3F2transitions, respectively. Furthermore, color coordinates of Pr3+ doped beta-eucryptite nanophosphors are well located in orange-red region. In the dispersion of ac conductivity over the frequency band comprises with two significant frequency nonresponsive and responsive conductive bands. The luminescent unclonable security ink is prepared using Pr3+doped beta-eucryptite nanophosphorsto encode security labels and are completely invisible under normal white light, while it exhibits clear orange-red emission upon ultraviolet 365 nm light. The overall aforementioned results clearly validated that the Pr3+doped beta-eucryptitenanophosphors is establish to be a suitable component for multifunctional applications.

Zinc ferrite nanoparticles: simple synthesis via lyophilisation and electrochemical application as glucose biosensor

With increasing diabetes patients in the near future, development of non-enzymatic glucose biosensor is highly demanded due to their greater sensitivity and resistance to external stimuli compared to enzymatic biosensors. Zinc ferrite (ZnFe2O4, ZFO) nanoparticles (NPs) were fabricated using a simple solution combustion method together with freeze drying. The NPs have high crystallinity, large aspect ratios and narrow size distributions. Plenty of defects have been induced during lyophilisation and greatly improves the glucose biosensing performance during electrochemistry test. The freeze-dried ZFO NPs are highly crystalline and agglomeration-free, these assures the sample with high sensitivity, superior selectivity, low detection limit and outstanding stability for electrochemical glucose biosensing.

P2-Type Na0.67Mn0.5Fe0.5O2 Synthesized by Solution Combustion Method as an Efficient Cathode Material for Sodium-Ion Batteries

P2-type sodium transition metal oxide materials have a high theoretical capacity (∼170–210 mAh g−1) and exhibit high sodium-ion diffusion rates. In the present work, we report P2-type Sodium layered transition metal oxide Na0.67Mn0.5Fe0.5O2 material prepared by the simple solution combustion method followed by thermal treatment is studied as a promising cathode for Sodium-ion Batteries (SIBs). The formation of a pure hexagonal crystal system P2- Na0.67Mn0.5Fe0.5O2 with P63/mmc phase having plate-like morphology is confirmed. The electrochemical performance of the P2- Na0.67Mn0.5Fe0.5O2 as cathode for Sodium-ion Batteries shows an initial discharge capacity of ∼166 mAh g−1 with a moderate capacity retention of ∼111 mAh g−1 at a 0.1 C rate for 100 cycles. Further, the C rate performance of the material shows a reasonable capacity of >95 mAh g−1 at a 1 C rate. The slow decrease in performance during cycling of Na0.67Mn0.5Fe0.5O2 cathode is due to surface reconstruction, intragranular cracks, transition metal reduction and dissolution, and electrolyte decomposition which is evident from various surface studies. The P2-Na0.67Mn0.5Fe0.5O2 exhibits stable cycling and C-rate performance between 0.1C–1C which is superior to many of the literature results.

Influence of fluorine doping of zinc oxide on its electrochemical performance in supercapacitors

Fluorine doped ZnO particles were prepared by a simple solution combustion method using glycine as a fuel. The effects of fluorine doping on the microstructure and supercapacitive performances on the ZnO based electrode materials were investigated. The electrochemical properties of the electrode materials were investigated through potentiometer, galvanostatic, and charge/discharge measurements in a 3 M KOH electrolyte. It was found that the fluorine-doped ZnO electrodes display much higher specific capacitances and better cycle stability than undoped ZnO electrodes. Specifically, fluorine-doped ZnO exhibits a high specific capacitance of 12.2 F/g at a scan rate of 10 mV/s compared to that of ZnO (3.39 F/g) and retained approximately 91.5% of its initial capacitance after 4000 charge/discharge cycles. Moreover, the fluorine-doped ZnO exhibited a high energy density of about 11.2 Wh/kg at a power density of 250 W/kg when compared with ZnO (~1.39 Wh/kg). The experimental results revealed that the supercapacitive performance of ZnO can be enhanced by fluorine doping.

Enhanced Photocatalytic Activity and Electrochemical Behaviour Towards Hg(II) of CeO2:Ag Nanocomposite

CeO2 and CeO2:Ag nanocomposite were synthesized using succinic acid as a fuel by a simple solution combustion method. This method neither demands surfactants nor long reaction time. Synthesized materials were identified through several analytical tools such as photoluminescence spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, scanning electron microscopy and x-ray diffraction. The photocatalytic activity of prepared nanomaterials were investigated by the photodegradation of trypan blue dye by varying the initial dye concentration and catalyst dosage. The result revealed that CeO2:Ag nanocomposite have shown the better photocatalytic activity than the CeO2 nanoparticle at pH 5 under ultraviolet light irradiation. Furthermore, CeO2:Ag nanocomposite is immobilized and electrically wired via immobilization upon glassy carbon electrodes to permit the creation of CeO2:Ag nanocomposite electrochemical sensor, which has been successfully evaluated for sensing Hg(II) at nano-molar (nM) levels in model aqueous solutions across dissimilar pulse anodic striping voltammetry.

Effect of CeO2-ZnO Nanocomposite for Photocatalytic and Antibacterial Activities

The impact of a CeO2-ZnO nanocomposite on the photocatalytic and antibacterial properties compared to bare ZnO was investigated. A CeO2-ZnO nanocomposite was synthesized using Acacia nilotica fruit extract as a novel fuel by a simple solution combustion method. The obtained CeO2-ZnO nanocomposite was confirmed structurally by XRD, FTIR, Raman and UV-DRS and morphologically by SEM/TEM analysis. The XRD pattern indicates the presence of both hexagonal Wurtzite-structured ZnO (major) and cubic-phase CeO2 (minor). FTIR shows the presence of a Ce-O-Ce vibration at 468 cm−1 and Zn-O vibration at 445 cm−1. The existence of a band at 460 cm−1 confirmed the F2g Raman-active mode of the fluorite cubic crystalline structure for CeO2. Diffused reflectance spectroscopy was used to estimate the bandgap (Eg) from Kubelka–Munk (K–M) theory which was found to be 3.4 eV. TEM analysis shows almost spherical-shaped particles, at a size of about 10–15 nm. The CeO2-ZnO nanocomposite shows a good BET specific surface area of 30 m2g−1. The surface defects and porosity of the CeO2-ZnO nanocomposite caused methylene blue (MB) dye to degrade under sunlight (88%) and UV light (92%). The CeO2-ZnO nanocomposite also exhibited considerable antibacterial activity against a pathogenic bacterial strain.

Synthesis and characterisation of CdO nanoparticles: An efficient nanomaterial for the removal of Rhodamine B

An Environmentally friendly method is reported for the synthesis of nanoscale CadmiumOxide using plant extract as a reducing agent. Cadmium oxide was synthesised by a simple solution combustion method using Cadmium Chloride monohydrate and Phyllantus Emblica extract and calcined at elevated temperatures. Biosynthesised CadmiumOxide Nanoparticles (CdONPs) was calcinated at different temperatures like 70, 200, 400 and 600 °C. CdONPs calcined at higher temperature was appraised for the removal of Rhodamine B (RhB) from aqueous solution. The developed adsorbent was characterized by TGA, DTA, FTIR, XRD, FESEM, EDAX and TEM. XRD revealed that Cd(OH)2 nanoparticles with hexagonal structure transform into CdONPs with cubic structure. The adsorption ability of the CdONPs was systematically investigated using batch experiments. The factors investigated include initial concentration, adsorbent dosage, contact time and pH. The CdONPs, calcined at 600 °C exhibit good nanomaterial for the removal of RhB (93% degradation of RhB for 0.1 g dosage within 80 min). Adsorption follows Langmuir isotherm and ΔG° = −79.55 KJ/mol indicates that the adsorption is chemisorption and spontaneous. The kinetic data for the adsorption process obeyed a pseudo-second-order kinetic model with R2 of 0.99. Present work has proved that CdONP is a novel low-cost nanomaterial and plays an important role in environmental protection.

Implementing an in-situ carbon formation of MoO3 nanoparticles for high performance lithium-ion battery

MoO3 is passionately examined as anode materials for lithium-ion batteries (LIBs), because of its exclusive interest due to high theoretical capacity (1117 mAhg−1). This article reports the synthesis of MoO3 nanoparticles by a simple solution combustion method using tamarind seed powder as a novel fuel where it produces in situ excess carbon by which it can eliminate the addition of acetylene black during the preparation of electrodes for LIB as a conducting material. The prepared MoO3 nanoparticles were characterized by XRD for structural analysis, vibrational bonding's through FTIR, CHN elemental analysis, BET for pore size distribution and specific surface area, morphology by SEM and TEM. Presence of carbon content in MoO3 nanoparticles show an excellent electrochemical performance by showing initial discharge capacity of 1171 mAhg−1 and stabilized to 162 mAhg−1 after 200 cycles and Columbic efficiency close to 100%.

Combustion synthesis of β-SnWO4-rGO: Anode material for Li-ion battery and photocatalytic dye degradation

This article reports the synthesis β-SnWO4–rGO nanocomposite (NC) by a simple solution combustion method followed by low temperature hydrothermal method. The β-SnWO4–rGO NC has been characterized using various analytical tools such as X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), High-Resolution Transmission Electron Microscopy (HR-TEM), Ultraviolet-Differential reflectance spectroscopy (UV-DRS). X-ray diffraction pattern shows the formation of cubic structured β-SnWO4 nanoparticles (NPs) and Raman spectrum shows the presence of rGO in the composite. Transmission Electron Microscopy image shows that SnWO4 NPs were embedded on the surface of rGO. β-SnWO4 NPs and β-SnWO4-rGO NC has been examined as an electrode material for Li-ion battery (LIB). β-SnWO4 NPs and β-SnWO4-rGO NC displays an initial discharge capacity of 1351 mAhg−1 and 1662 mAhg−1 which is about 23% increase in capacity. Electrochemical performance of β-SnWO4-rGO NC at different current densities proves that it is one of the good candidates as an electrode material for LIB. β-SnWO4-rGO NC shows enhanced photocatalytic activity against rose bengal (RB) and methylene blue (MB) compared to pure β-SnWO4 NPs.

Nano Sized ZnO/MnO2/Gd2O3 Ternary Heterostructures for Enhanced Photocatalysis

Background: The cost of effluent treatment is not affordable by small scale industries especially in developing countries. Hence the effluent is discharged without treatment into water bodies. The dyes do not degrade easily and possess a major concern to be addressed. The aquatic life is highly affected and also leads to bio magnification of the chemicals through the food chain. Objective: To synthesize a ternary hybrid structure for enhanced photocatalytic activity under visible light. It is intended to reduce toxicity caused by dyeing units. Methods: Synthesized nanomaterials are characterized and used as photocatlyst for the degradation of methylene blue. In degradation experiment known weight of catalyst was added to known volume of an aqueous solution of dye at various concentrations. The solutions are aerated in dark for about 30 min. At the time of irradiation of light, known aliquot of the aqueous mixture was collected at an interval of constant time each from the reaction solution. The catalyst in the mixture was separated by centrifuging the mixture and absorbance was measured. The % of degradation of the dye can be determined knowing initial and final dye concentration. Result: Heterostructures are characterized with analytical tools such as X-ray diffraction, Fourier transform infrared spectroscopy. Band gap of photocatlyst is calculated by application of UV-Vis spectroscopy. Morphology is seen using scanning electron microscopy and transmission electron microscopy. Distribution of constituent structures is observed with energy-dispersive X-ray (EDX) spectroscopy. The structures are used for photocatalytic degradation of methylene blue dye solution under UV and visible light irradiation. Heterostructures showed best performance under visible light. Conclusion: The ternary hybrid nanostructure ZnO-MnO2-Gd2O3 was effectively prepared by a simple solution combustion method. The ternary compound shows wide range of absorption by expanding absorption band both in UV and visible regions. Structures showed better catalytic property under visible light.

Effect of ignition temperature and fuel amount on photocatalytic activity of solution combustion synthesized ZnO

Nanocrystalline zinc oxide (ZnO) photocatalyst has been synthesized by a simple solution combustion method using zinc nitrate as the oxidizer and urea as the fuel. Effect of fuel to oxidizer ratio and ignition temperature on the mechanism of combustion synthesis, crystallinity, morphology, surface area, and optical properties were investigated by thermal analysis, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Diffuse reflectance UV–Visible spectra and Photoluminescence analyses. Photocatalytic activity of the synthesized materials was evaluated by degrading an azo dye at ambient temperature and solution pH. The prepared photocatalysts at the fuel-rich condition possess small crystallite size and more surface area; consequently, a higher photocatalytic dye degradation capability.The powder samples synthesized at the fuel-oxidant ratio of 1.8 and the ignition temperature at 400 °C have shown the maximum percentage (99%) of dye degradation in 180 min. The pseudo-first order photocatalytic dye degradation rate constant of a catalyst sample synthesized at the fuel-oxidant ratio of 1.8 was 0.0253 min−1and it is 3.14 and 2.88 times higher than that of samples synthesized at fuel-oxidant ratios of 0.6 and 1.The outcomes of the present article help to design more pronounced experiments for the synthesis of photocatalysts by varying ignition temperatures and fuel amounts.

Effect of Al-Doping on the Electrochemical Performances of O3-Type Nanmc Cathode Material for Sodium-Ion Batteries

The emergence of Lithium-ion technology as a primary power source has revolutionized the global electric vehicle battery market, the high abundance, uniform geological distribution and similar electrochemistry of sodium, making sodium-ion batteries (NIBs) a promising LIB supplement in the large-scale energy storage applications1,2. Layered sodium transition metal oxide of O3-NaMO2-type such as NaCoO2, NaMnO2, NaNiO2, and NaFeO2, etc. have been investigated to show reversible Na-ion insertion within the applied potential limit 2,3. They suffer from their characteristic disadvantages, such as low redox potential of NaCoO2, complex phase transition of NaNiO2, electrolyte dissolution of Mn+2 of NaMnO2 and rapid capacity fading of NaFeO2 4,5. Therefore, the strategy of cation mixing to develop the multi-metallic oxides has been explored well to utilize the synergistic effects of all metal ions. O3-type layered NaNi0.5Mn0.3Co0.2O2 is considered as one of the most promising cathode materials for NIBs. O3-NaNi0.5Mn0.3Co0.2O2 as cathode material for SIBs delivers a 1st cycle capacity of 135 mAh g-1 with the 37% capacity fade at the end of 200th cycle at C/10 current rate.NaNi0.5Mn0.3Co0.2O2, synthesized by using simple solution combustion method followed by thermal treatment delivers an initial discharge capacity of 135 mAh g-1 at C/10 rate, which indicates a reversible insertion of ~50% sodium. However, it loses 37% of the initial capacity after 200 cycles due to structural deformation during sodiation/de-sodiation process. The irreversible phase transition due to structural deformation leads to sluggish kinetics, rapid capacity fade, and poor rate performance; thereby limit its wide practical applications. To mitigate structural instability and rapid capacity fading, doping of main-group metals within transition metal layers is an effective strategy.6-8 The partial substitution of Co3+ (0.545 Å) by Al3+ (0.535 Å) ions in the transition-metal layer to synthesize NaNi0.5Mn0.3Co0.2-xAlx (x=0.01, 0.02, 0.05) by solution combustion technique is an effective strategy to address the issue of structural deformation and thus to improve the performance of NaNi0.5Mn0.3Co0.2O2. The O3-type structure of the synthesized material with the R-3m space group was confirmed from XRD analysis. The synthesized materials show morphology of hexagonal plate-like primary structures aggregated to form secondary clusters. The galvanostatic charge-discharge studies carried out at C/10 rate in the voltage range of 2.0-4.0 V shows that the composition with an overall 2% Al doping (x=0.02) delivers much better capacity retention (~28% improvement than pristine NaNMC) even after 100 cycles than the other compositions studied (1% (x=0.01) and 5% (x=0.05) Al doping). Moreover, the NaNi0.5Mn0.3Co0.18Al0.02O2 shows the good capacity of around 80 mAhg-1 even at high C-rate of 5C rate, which is almost 72% of the initial capacity at C/10 rate. The improved electrochemical performance of the Al-substituted NaNMC is attributed to the enhanced structural stability of the sodium layered transition metal oxide achieved after the partial substitution of Co3+ by Al3+ ion.

Effects of temperature on luminescent properties of Gd2O3:Er, Yb nanophosphor

In this study we analyze nano powder Gd2O3 doped with Er3+ and Yb3+. Material was synthesized by simple and efficient solution combustion method. The nano phosphor was optically excited at 980 nm by using pulsed laser diode. We have obtained time resolved upconversion luminescence spectra of nano powder samples of Gd2O3:Er,Yb using a streak camera and analyzed temperature dependence of erbium optical line emission intensities. The possibilities of using Gd2O3:Er,Yb for temperature sensing were analyzed by means of luminescence intensity ratio method. We show that synthesized Gd2O3:Er,Yb material is useful for temperature measurements up to 550 K.

Solution Combustion Synthesis of Porous MgO Nanostructures for Efficient Removal of Congo Red.

Porous MgO nanostructures were synthesized in large-scale by a simple solution combustion method using citric acid and glucose as the fuel. The resulting porous nanostructure powders were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and N₂ adsorption-desorption isotherms. The SEM and TEM images demonstrated that the type of fuel used during the combustion synthesis strongly affects the morphology and structure. The use of glucose aggregated the structure with majority particle sizes in the range 3560 nm and a surface area of 40.55 m²g-1, while the use of citric acid results in a large network structure with smaller particle sizes (30-50 nm) and a larger surface area of 53.88 m²g-1. The two samples synthesized from glucose and citric acid exhibited excellent adsorption performance for Congo red with the maximum capacity reaching 1500.98 mg g-1 and 1638.08 mg g-1, respectively. These results indicate that the porous MgO synthesized by the solution combustion is a potential candidate for the removal of pollutant dye in water.

Constructive Interfacial Charge Carrier Separation of a p-CaFe2O4@n-ZnFe2O4 Heterojunction Architect Photocatalyst toward Photodegradation of Antibiotics.

Charge dynamics across the interfacial junction of p-n heterostructures leading to effective charge separation along with notable photodurability are essential preconditions to achieve high photocatalytic activity. The p-CaFe2O4@n-ZnFe2O4 (CFO@ZFO) heterojunction has been successfully synthesized by a simple solution combustion method followed by the ultrasonication technique. XRD and HRTEM studies confirmed the effective interaction and formation of the CFO@ZFO heterojunction. The loading of CFO over ZFO selectively enhanced the intensity of the (111) plane of active ZFO, leading to greater crystallinity and a suitable heterojunction which triggers the photocatalytic reaction. The result shows that a 40% loading of CFO on ZFO makes it the flagship photocatalyst. The impedance and PL spectra of 40%CFO@ZFO confirmed the low electron-hole recombination in comparison to the neat materials. Bode phase analysis showed that the lifetime exciton in 40%CFO@ZFO is 1.35 times superior to that of pure ZFO. The heterostructure results in enhancement of the photocurrent in the anodic direction, i.e. 6.6 mA/cm2, which is nearly 2 times greater that of the neat materials. The 40%CFO@ZFO shows the best activity toward degradation of 20 ppm tetracycline and ciprofloxacin, i.e. 89.5% and 78%, respectively, in 1 h. The efficient charge separation at the interface, low charge transfer resistance, formation of heterostructures, and high value of synergy factor are collectively responsible for the best activity in 40%CFO@ZFO.

Solid-state lithium metal batteries enabled with high loading composite cathode materials and ceramic-based composite electrolytes

The solid-state lithium batteries (SSLBs) are wide studied owing to its high safety and low cost. However, the poor ionic conductivity of solid electrolyte and low capacity of cathode limit its commercial application. In this paper, nanosized cubic phase Li6.75La3Zr1.75Ta0.25O12 powders is prepared via a simple solution combustion method and used to develop a ceramic-based composite solid electrolyte, which presents high ionic conductivity (1.05 × 10−4 S cm−1 at 25 °C), high lithium ion transference number tLi+ (0.74), wide electrochemical window (4.8 V vs. Li/Li+), excellent heat resistance and electrolyte-electrode interfacial stability. In addition, a high loading (~10.5 mg cm−2) LiNi0.5Co0.2Mn0.3O2 composite cathode with succinonitrile and lithium bis(trifluoromethanesulfonyl)imide as additives is used to fabricate SSLBs, which exhibits a high initial discharge capacity of 146.9 mA h g−1 and good capacity retention of 86.89% after 150 cycles at 0.1 C under 25 °C. The superior performance indicates that solid-state lithium battery assembled with composite solid electrolyte and high loading composite cathode provides a promising choice for the practical development of high-energy-density lithium batteries.

A novel Cs2O–Bi2O3–TiO2–ZnO heterostructure with direct Z-Scheme for efficient photocatalytic water splitting

Efficient production of hydrogen through photocatalytic water splitting requires innovative catalyst design. One of the potential ways to enhance the photocatalyst's efficiency is to prepare metal oxide heterostructures. Herein, we report fabrication of a novel heterostructure consisting of oxides of cesium, bismuth, titanium and zinc (Cs2O–Bi2O3–TiO2–ZnO) by a simple solution combustion method. Diffusion pathway of charge carriers in the as-synthesized Cs2O–Bi2O3–TiO2–ZnO is investigated by high resolution Valence Band X-Ray Photoelectron Spectroscopy (VB-XPS) and electron spin resonance studies. On the basis of analytical findings and redox potential values of each photocatalytic component, a plausible mechanism is proposed showing the formation and diffusion of charge carrier. The results suggest that the charge carrier migration follows the heterojunction approach among TiO2, Bi2O3, and ZnO and the Z-scheme approach between each of them and Cs2O. The performance of the as-obtained catalytic system is investigated by quantifying the photocatalytic formation of oxygen and hydrogen gases, as well as photoelectrochemical water oxidation under simulated sunlight irradiation. In addition, the apparent quantum efficiency is estimated as high as 1.56% at 420 nm. The high apparent quantum efficiency is primarily ascribed to the synergetic effect between Z-scheme and heterojunction operative in the as-prepared heterostructure.

Nano zinc ferrite modified electrode as a novel electrochemical sensing platform in simultaneous measurement of trace level lead and cadmium

Nano sized zinc ferrite (ZnFe2O4) particles have been synthesized by a simple solution combustion method and its electrochemical sensing application has been reported after modifying the glassy carbon electrode with thin film of zinc ferrite. The nanoparticles have been characterized by FTIR, XRD, BET, FESEM and TEM techniques to ascertain the particle size and its surface morphology. It has been used as an electrochemical sensing tool in the simultaneous measurement of lead and cadmium ions at trace level by differential pulse anodic stripping voltammetry (DPASV). All the experimental variables have been optimized and it has been utilized in real sample analysis. The sensor exhibited wide linearity in the concentration range 10–130 ppb with detection limits of 1.12 and 2.52 ppb for lead and cadmium metal ions, respectively.