Soft Chemical Process Research Articles

Structural, morphological, and optical properties of praseodymium and aluminium codoped ZnO nanoparticles

Using a soft chemical process that involves nitrates and heat annealing, nanoparticles of undoped ZnO and praseodymium, aluminum-codoped ZnO may be produced. XRD, SEM with EDS, and FTIR analysis determine nanocatalyst structures, morphologies, and chemical bonding. PL and UV spectroscopy examines optical characteristics. The peak in the FTIR spectral line at 714 cm-1 in the study indicates M-O stretching in the samples and ZnO's interaction with the Pr and Al matrix. XRD patterns indicated prepared nanoparticles with nanosizes ranging from 40.07 to 38.65 to 36.84 to 38.87 to 39.91 nm. SEM analyzed nanoparticle size, shape, and interaction with the Pr and Al matrix. EDS determined NPs purity. UV-vis spectra of ZnO-Pr/Al nanocomposites showed UV absorption similar to ZnO nanoparticles. Doping ZnO with Pr and Al shrinks the bandgap and slows photogenerated electron-hole pair recombination without changing its crystalline structure.

The influence of Eu3+ doping on the optical and structural properties of the Ge2Y2O7 crystalline phase through a soft chemical process

The present work reports on the synthesis, structural and optical properties of Ge2Y2-xEuxO7 composition powders, with x ranging from 0.0 to 0.16 (from 0.0 to 4.0 mol% Eu3+). We synthesized stable and transparent sols, homogeneous gels, and powders treated at 1100 °C by a soft chemical route, and the effect of Eu3+ concentrations was evaluated. X-ray diffraction (XRD), infrared vibrational spectroscopy (FTIR), Raman spectroscopy, diffuse reflectance spectroscopy (DRS), emission and excitation photoluminescence spectroscopy (PL, PLE), decay curves of emission intensity as a function of time and quantum yield were obtained. An annealing temperature of 1100 °C was enough to obtain a single Ge2Y2O7 crystalline phase and the decrease of Χ2 value (from 2.32 to 1.74) with the increase of Eu3+ doping in the matrix, observed with the Rietveld refinement of the XRD patterns of the samples, is due to the crystallization process. Diffuse reflectance spectra and optical bandgap of 4.7 eV for Ge2Y0.88Eu0.12O7 (3.0 mol% Eu3+) – determined by Kubelka- Munk model – showed the good optical quality of the samples, which were considered non-conducting. All doped samples possessed visible photoluminescence emission from Eu3+ ions under excitation at 394 nm, with higher emissions occurring in the red region from 5D0 → 7F2 transition, with R/O relation equal to 2.6 and purity of red color higher than 85 % for the sample with x = 0.012. Analyzing photoluminescence emission spectra, the lifetime values and Judd-Ofelt parameters, we determined that Eu3+ occupied two different sites of the Ge2Y2O7 host matrix, replacing Y3+ ions, with the quenching concentration occurring between x = 0.12 and x = 0.16. The average decay lifetime of 5D0 level from Eu3+ was around 1.66 ms, with average quantum efficiency around of 48 % and an internal quantum yield equal to 7.17 %. Moreover, we evaluated their emission luminescence properties upon 394 nm excitation to explore for the first time the possibility of using this material in thermal sensing applications.

Porous chitosan-infused graphitic carbon nitride nanosheets for potential microbicidal and photo-catalytic efficacies

Supply of safe drinking water is a high-risk challenge faced internationally. Hybrid technologies involving nanomaterials can offer possible solutions to this research involving natural biopolymers. Porous chitosan with a high specific surface area has promising properties but its use as a membrane component in water purification is still rarely reported. Graphitic carbon nitride (g-C3N4) is a carbon nitride allotrope with a graphene-like layered structure that gifts unfamiliar physicochemical properties due to the presence of s-triazine fragments. It is a metal-free semiconductor with a band gap of ∼2.7 eV to ∼3.7 eV; which shows better visible light-activated photocatalyst properties. This work aims at synthesizing graphitic carbon nitride–biopolymer composite and exploring its properties in the field of wastewater treatment. The samples were synthesized via a soft chemical process with urea, as the source material. The flake-like morphology is displayed in the microstructural SEM image. The composition of the material was analyzed using EDS. Thermogram shows that the material is stable up to 500 °C and also confirms the formation of graphitic carbon nitride. In XRD spectra the intensity reduction shows the chitosan inclusion at the nitride site. The band gap of the prepared material was identified to be 2.3, 2.4 eV. The structural properties were analyzed using Fourier Transform Infrared Spectrometer and Raman spectroscopy. FTIR spectra and Raman spectra indicate the stretching vibration modes of CN and CN heterocycles and chitosan inclusion in the carbon nitride network. The photocatalytic activity was done in sunlight and a UV lamp with different dyes for doped and undoped g-C3N4. The doped (Porous/Non-porous chitosan) g-C3N4 showed faster dye degradation in sunlight compared to UV light. A biomolecular interaction study was done using Bovine serum albumin. It shows the material interaction with the BSA protein. The anti-microbial activity was performed on the Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli by disk diffusion method, the chitosan doped g-C3N4 showed good inhibitions against bacterial growth. The current work reveals the impact of nanoscale chitosan nanostructures doped on the optical, microstructural, catalytic, and antimicrobial properties of g-C3N4 nanosheets. This work provides new research options for nanocomposite-based photocatalytic nanomaterial g-C3N4 so that the quality of contaminated water could be improved.

Photocatalytic transfer of aqueous nitrogen into ammonia using nickel-titanium-layered double hydroxide.

The development of solar-driven transfer of atmospheric nitrogen into ammonia is one of the green and sustainable strategies in industrial ammonia production. Nickel-titanium-layered double hydroxide (NiTi-LDH) was synthesised using the soft-chemical process for atmospheric nitrogen fixation application under photocatalysis in an aqueous system. NiTi-LDH was investigated using advanced characterisation techniques and confirmed the potential oxygen vacancies and/or surface defects owing to better photocatalytic activity under the solar spectrum. It also exhibited a bandgap of 2.8eV that revealed its promising visible-light catalytic activities. A maximum of 33.52µmol L-1 aqueous NH3 was obtained by continuous nitrogen (99.9% purity) supply into the photoreactor under an LED light source. Atmospheric nitrogen supply (≈78%) yielded 14.67µmol L-1 aqueous NH3 within 60min but gradually reduced to 3.6µmol L-1 at 330min. Interestingly, in weak acidic pH, 20.90µmol L-1 NH3 was produced compared to 11.51µmol L-1 NH3 in basic pH. The application of NiTi-LDH for visible-light harvesting capability and photoreduction of atmospheric N2 into NH3 thereby opens a new horizon of eco-friendly NH3 production using natural sunlight as alternative driving energy.

Synthesis and Investigation of Pure and Cu-Doped NiO Nanofilms for Future Applications in Wastewater Treatment Rejected by Textile Industry

Pure and Cu-doped NiO films were synthesized via a soft chemical process. They were deposited on glass substrates heated to 400 °C. Different atomic percentage ratios (2, 4, 6, 8, and 10%) of Cu-doping were used. The prepared samples were characterized by several techniques such as X-ray diffraction for crystallographic study, SEM and AFM for microstructural and morphological properties, and UV-Visible spectroscopy for optical and photocatalytical analysis. XRD results of pure and Cu-doped NiO films indicated the formation of NiO polycrystalline phases under a cubic structure with a favored orientation along the (200) plane noticed in all sprayed films. SEM images revealed the formation of NiO nanoparticles of spherical forms whose sizes increase and agglomerate with increasing Cu-doping. At 10% Cu-doping, NiO agglomeration was extended to the whole surface. AFM images showed a textured and rough surface composed of NiO nanoparticles of average size varying from 16 to 10 nm depending on Cu-doping concentration. UV-visible spectroscopy confirmed the transparency of NiO films and their semiconducting character with a band gap ranging from 3.4450 eV to 2.8648 eV. The photocatalytical properties of pure and Cu-NiO films were enhanced by Cu-doping particles as revealed by the degradation of methylene blue (MB) solution subjected to irradiation.

Optical and Structural Characteristics of Rare Earth-Doped ZnO Nanocrystals Prepared in Colloidal Solution

ZnO nanocrystals doped with Nd, Gd, and Er were synthesized using a soft chemical process in ambient atmosphere. Pseudospherical and hexagonal nanocrystals (NC) of the wurtzite phase with a mean size of (7.4 ± 1.7) nm were obtained. The presence of rare earth (RE) dopants was confirmed by X-ray fluorescence (XRF) spectroscopy. The ZnO nanocrystals exhibited simultaneously narrow excitonic- and broad trap/surface-related photoluminescence (PL), both of which were affected by doping with RE atoms. Doping reduced the total PL intensity, suppressing the excitonic emission by a greater extent than the broad band PL. Also, doping resulted in a blue shift of the trap/surface-related emission, while the energy of the excitonic peak remained unchanged. Resonant Raman spectra additionally confirmed the wurtzite phase of ZnO NCs and revealed a shift of the A1-LO mode towards lower frequency upon doping that could be caused by the mass effect of RE atoms, point defects, and increases in charge carrier concentration. Fitting of the spectra with Voigt profiles showed better results with two surface optical (SO) phonon modes that were previously theoretically predicted for the wurtzite ZnO phase. The influence of RE doping on PL and Raman spectra can be explained by the incorporation of RE ions into the ZnO nanostructures, where the dopants act as non-radiative defects.

Lanthanum oxide rods as a novel and efficient bifunctional hydrogen and oxygen evolution electrocatalyst for overall water splitting

Novel and efficient catalytic materials with enhanced electrocatalytic properties are needed for hydrogen production from water through electrochemical water splitting. In this study, novel lanthanum oxide rods were prepared using a facile, soft chemical process. These lanthanum oxide rods were used for electrocatalytic hydrogen and oxygen evolution reactions. Electrochemical studies of the catalyst at 100 mA cm−2 indicated overpotentials of ∼340 and ∼405 mV for hydrogen and oxygen evolution reactions, respectively. In addition, the lanthanum oxide rods demonstrated good stability. Finally, lanthanum oxide rods were used as the cathode and anode to fabricate the electrolyzer in a two-electrode configuration. This electrolyzer required 1.6 V to drive 10 mA cm−2, and its performance did not change significantly during durability testing. To the best of our knowledge, this is the first study demonstrating the use of lanthanum oxide rods in electrocatalysis. The prepared lanthanum oxide rods have good electrocatalytic activity, and therefore, they are promising materials for the development of alkaline electrolyzers.

High entropy spinel metal oxide (CoCrFeMnNi)3O4 nanoparticles as novel efficient electrocatalyst for methanol oxidation and oxygen evolution reactions

In this work, (CoCrFeMnNi)3O4 high entropy spinel oxide-based electrocatalyst is prepared using a facile soft chemical process. The synthesized catalyst has a spherical morphology. The formation of the pure phase material is confirmed using spectroscopic and microscopic studies. The prepared material is used as an electrocatalyst for the methanol oxidation and oxygen evolution reactions. The slurry of the as-synthesized material is coated on nickel foam and used as a working electrode. For methanol oxidation, the catalyst showed a specific current density of ~335 mA cm−2. The observed mass-activity of the catalyst is ~110 mA mg−1 with an observed onset potential of ~0.45 V. For the oxygen evolution reaction, the onset potential of (1.45 V vs. RHE) is observed with a low overpotential of 220 mV at 10 mA cm−2. The corresponding Tafel slope is ~100 mV dec−1. These results showed that the prepared high entropy oxide showed efficient electrocatalytic activity, and they are promising for methanol oxidation and oxygen evolution reactions. This is the first report demonstrating the spinel-type high entropy oxide nanoparticles in electrocatalysis to the best of our knowledge.

Synthesis and Characterization of Undoped and Mn‐Doped Copper Oxide Nanoparticles

AbstractCopper oxide (CuO) is a p‐type metal‐oxide semiconductor with a bandgap of 1.2 eV and a minimal bandgap. Solar cells, superconductors, and sensors are among the applications for which it is used. To dope transition metals, researchers use a low‐cost soft chemical process (Mn). The aim of this research is to identify CuO nanopowders using a low‐cost soft chemical method to dope transition metals (Mn). The nanopowders' structural, morphological, functional, and optical properties are investigated. X‐ray diffraction (XRD) analysis findings point to the synthesis of high purity single monoclinic phase CuO nanoparticles. The crystallite size (30 nm) and lattice parameters of Mn‐doped CuO samples are reduced. These results suggest that Mn‐doped CuO nanoparticles may be a promising candidate for optoelectronic devices and photocatalytic organic compound degradation.

Mo-Doped SnO2 Quantum Dots Dispersed Over Reduced Graphene Oxide Sheets as an Efficient Anode Material

Abstract We explore the effect of Mo doping over the large enhancement of electrochemical property of Mo-doped SnO2 quantum dots (3–5 nm) grown over rGO (reduced graphene oxide) sheets by a soft chemical process in ambient conditions. The composites were prepared over a range of Mo doping concentrations (0–10%) and 5% Mo doping had achieved the best energy storage characteristics. The capacity of the active material could reach ∼851 mAh g−1 (@ 78 mA g−1) in the beginning and that retained ∼89% (∼758 mAh g−1) with superior cyclic stability (100 cycles) and rate capability (506 mAh g−1 @ ∼1.5 A g−1). The addition of the reductant of 0.06 mol during the synthesis procedure led to further improvement of the capacity to ∼875 mAh g−1 (∼92% retention) and the rate capability (∼587 mAh g−1). These impressive results are ascribed to the distribution of Mo-doped SnO2 QDs, doping of Mo6+ at Sn4+ lattice sites providing more electrons for easy electrical transport, reduction of GO (graphene oxide) to rGO. Mo doping led to the decline in the charge transfer resistance (Rct) from 14.99 Ω for un-doped SnO2/rGO to 14.09 Ω (2.5%), 11.61 Ω (5%), and 11.4 Ω (10%) and promote the electrochemical property of the composite. A simple room-temperature synthesis process was used to produce Mo-doped SnO2/rGO nanocomposite and can be employed for the production of many other oxides and their composites for interesting applications.

Soft chemical processing approach for the valorization of seafood waste by-products as a source of bioactive polymers

Abstract Chitin and chitosan as green and active biomacromolecules were extracted from local seafood waste (shrimp shells). The extraction was carried out by a soft chemical process, followed by structural characterization (FTIR, XRD, viscosity average molecular weight M̅v), thermal stability by TGA, and antibacterial tests. FTIR and XRD spectra confirmed the chemical structures of the extracted chitin and chitosan which were similar to the commercial ones. The chitin and chitosan had an average viscosimetric molar weight of 232.21 kDa and 41 kDa, respectively. The chitosan had a high deacetylation degree (DD = 71 %) and low cristallinity index (Icr = 68.3 %); compared to chitin, which exhibited a lower deacetylation degree (DD = 24.27 %), higher thermal stability and higher cristallinity index (Icr = 87.55 %). A bacteriostatic effect of chitin was observed in the gram-negative bacteria, Escherichia coli, Salmonella typhimurium. Chitosan exhibited a bacteriostatic effect on all bacteria tested, except Salmonella typhimurium.

High-performance p-channel transistors with transparent Zn doped-CuI

‘Ideal’ transparent p-type semiconductors are required for the integration of high-performance thin-film transistors (TFTs) and circuits. Although CuI has recently attracted attention owing to its excellent opto-electrical properties, solution processability, and low-temperature synthesis, the uncontrolled copper vacancy generation and subsequent excessive hole doping hinder its use as a semiconductor material in TFT devices. In this study, we propose a doping approach through soft chemical solution process and transparent p-type Zn-doped CuI semiconductor for high-performance TFTs and circuits. The optimised TFTs annealed at 80 °C exhibit a high hole mobility of over 5 cm2 V−1 s−1 and high on/off current ratio of ~107 with good operational stability and reproducibility. The CuI:Zn semiconductors show intrinsic advantages for next-generation TFT applications and wider applications in optoelectronics and energy conversion/storage devices. This study paves the way for the realisation of transparent, flexible, and large-area integrated circuits combined with n-type metal-oxide semiconductor.

Hierarchical porous ε-MnO2 from perovskite precursor: Application to the formaldehyde total oxidation

A simple template-free method, based on a mineral acid etching process using manganite perovskite (LaMnO3) as precursor, was successfully developed to obtain a series of 3D meso/macro-porous materials. The LaMnO3 transformation was fully investigated using ICP, XRD, N2 physisorption, TPR, TPD, SEM, TEM/EDS and XPS. This transformation proceeds through a soft-chemical process involving the dissolution of trivalent lanthanum and manganese from the perovskite structure and the dismutation of Mn3+ cations into MnO2 and Mn2+ species. Strength and oxidizing properties of the acid used as modifying agent strongly impact textural and redox surface properties of the resulting materials. Specifically, extending the acid etching duration promotes the surface area and pore volume of the materials while developing interconnected macro-mesoporous networks. In our case, this soft process allowed us to obtain the ε-MnO2 phase with hierarchical porosity without any template. Superior catalytic properties of ε-MnO2 were observed toward HCHO oxidation as well as a good catalytic stability with respect to other macro-mesoporous counterparts. In the light of the experimental results, such performances can be related to the formation of a meso/macro-porous structure conferring high surface area and good accessibility of the active surface sites. The latter exhibit greater redox ability of the manganese species and a higher density of active surface oxygen species with respect to the perovskite precursor.

3D hollow sphere-like Cu-incorporated LaAlO3 perovskites for peroxymonosulfate activation: Coaction of electron transfer and oxygen defect

To develop an efficient catalyst with novel structure and limited metal release for enhanced PMS activation, a 3D hollow sphere like Cu-incorporated LaAlO3 perovskite was synthesized based on soft chemical process with template-free. It was evaluated as the heterogeneous catalyst firstly to activate peroxymonosulfate (PMS) for the oxidative degradation of several typical pharmaceuticals in water. The mechanism study indicated a coaction of electron transfer and oxygen defects in this system. The obtained catalyst can promote electron transfer efficiency of Cu+/Cu2+ cycle and provide abundant oxygen defects for catalytic oxidation, which is responsible for the generation of OH, SO4− and 1O2. These active species played crucial roles in efficient degradation of thiamphenicol (TAP), diclofenac sodium (DCF), ibuprofen (IBF) and paracetamol (PR), achieving more than 95% removal within 30 min. The catalyst kept high removal efficiency over pH range from 5.0 to 9.1 and suppressed copper leaching in reaction process. Besides, the catalyst exhibited good performance for TAP degradation and mineralization in raw water matrixes from Taihu Lake Basin, which showed a possible practical application to the remediation of water pollution.

Rod-like incipient ferroelectric SrTiO3 polycrystal with crystal-axis orientation

Strontium titanate (SrTiO3, ST) is an incipient ferroelectric material. Generally, a one-dimensional (1D) ST polycrystal is difficult to obtain because of its high aspect ratio and directional orientation. We prepared a 1D ST polycrystal from a layered H2Ti4O9·H2O (HT) single crystal via a solvothermal soft chemical process. The 1D ST polycrystal fabricated from ST nanocrystals has a [010] crystal axis, implying that it is a mesocrystal. The ST nanocrystals were grown not only on the surfaces but also in the interlayers of the original HT matrix. The formation mechanism of the ST mesocrystal is based on a topochemical mesocrystal conversion process. ST ceramics fabricated from ST mesocrystal powder present a lossy capacitor response and excellent energy-storage capabilities owing to the presence of locally oriented ST nanocrystals with a lattice mismatch in the rod-like ST mesocrystals. The investigations performed in this study can set a new benchmark for the development of new electric ST-based materials.

Microencapsulated PCMs for thermal energy storage in the range 300-500 °C: pilot-testing

Phase Change Materials (PCM) became one of the most interesting research directions toward improving the efficiency of concentrated solar power plants. Different methods were proposed to increase storage capacity as a result of the encapsulation protection and efficient thermal energy storage for high operating temperatures. Here, we present a soft chemical process to encapsulate inorganic KNO3 as PCM system using nanostructured ZnO shell material, based on hydrothermal synthesis followed by spray drying and their thermal conductivity measurements are discussed. A unique micro-pilot equipment for the functional characterization of microencapsulated PCMs was designed and built for real time monitoring of thermal properties of these materials.

Synergistic effect of Na and Se on CZTSe solar cells through a soft chemical process

Alkali metal can improve the chalcopyrite structured device performance. However, such alkali metal is normally doped by diffusing Na into absorber layer from soda-lime glass or by vacuum method. In this study, a soft chemical method is applied to dope Na into kesterite structured compound film. Combined by XRD, SEM, SIMS, and EDS mapping, it indicates that the NaF aqueous solution treatment provides a unique Na source, which can promote the film growth and the elements distribution, especially Se element distribution. The surface decomposition of CZTSe is suppressed because of the Na participating in crystallization at the beginning stage of the selenization process, which can improve the interface between CdS and CZTSe. The average conversion efficiency of solar cell is improved from 6.3% without such treatment to above 7.8% with such chemical treatment and the best 8.4% efficiency has been achieved for the 0.005 mol/L NaF treated CZTSe device. This facile Na aqueous solution treatment afford a unique insight and also enlarge the understanding on the Na treatment on compound semiconductor solar cells, which will promote the fabrication of chalcopyrite solar cell with high performance.

One-Dimensional Piezoelectric BaTiO3 Polycrystal of Topochemical Mesocrystal Conversion from Layered H2Ti4O9·H2O Single Crystal

A one-dimensional (1D) piezoelectric BaTiO3(BT) polycrystal with a tetragonal system was controllably prepared using a one-step hydrothermal soft chemical process. A layered H2Ti4O9·H2O (HTO) single crystal was used as the precursor. Interestingly, the obtained polycrystalline BT constructed from oriented BT nanoparticles shows a set of single-crystalline diffraction points, implying that the BT polycrystal is a mesocrystal. The [010] and [001] directions of the obtained mesocrystalline BT correspond to the [001] and [010] directions of the original HTO crystal, respectively, and the [010] direction of the mesocrystalline BT corresponds to the direction along the length of a 1D rod matrix. An in situ topochemical mesocrystal conversion of mesocrystalline BT grown on the HTO substrate occurred not only on the substrate surface but also in the interlayers owing to the unique TiO6 octahedral layers of HTO. In addition, the piezoelectric response of the 1D mesocrystal was captured for the first time. The piez...

Structural and spectroscopic properties of Eu3+ doped Y4Al2O9 compounds through a soft chemical process

The present work reports on the synthesis, structural and optical properties of (Y1-xEux)4Al2O9 powders, with x ranging from 0.001 to 0.030. We prepared the materials using a modified polymeric precursors method, and the effect of annealing temperature and Eu3+ concentrations were evaluated. Structural and microstructural parameters, such as cell parameters, crystallite size and grain size were determined and evaluated by using the results from X-ray diffraction and high-resolution transmission electron microscopy techniques. An annealing temperature of 800 °C was enough to obtain single Y4Al2O9 crystalline phase with good distribution of Eu3+ ions. Diffuse reflectance spectra and optical bandgap of 4.52 eV for (Y0.995Eu0.005)4Al2O9 – determined by Kubelka-Munk model – showed good optical quality of the samples, which were considered non-conducting. All doped samples possessed visible photoluminescence emission from Eu3+ ions under excitation at 393 nm, with higher emissions occurring in the red region from 5D0 → 7F2 transition, with R/O relation of 1.69 for the sample with x = 0.010. Analyzing photoluminescence emission spectra, the lifetime values and Judd-Ofelt parameters, we determined that Eu3+ occupied three different sites of the Y4Al2O9 (YAM) structure, replacing Y3+ ions, with the quenching concentration occurring between x = 0.020 and x = 0.030. We noted that Eu3+ ions are in a chemical environment with low polarization, and their degree of covalence is low. Finally, samples with x = 0.020 (Y0.980Eu0.020)4Al2O9 seems to be useful as red phosphors.

Enhanced antibacterial and photocatalytic activity of (Mg+Co) doped tin oxide nanopowders synthesised using wet chemical route

In this study, the photocatalytic activity of pristine and (Mg+Co) doped tin oxide (SnO2) nanopowders have been investigated towards the degradation of aqueous solutions of Methylene Blue (MB) and Malachite Green (MG). In addition, the antibacterial activities of the synthesised samples were evaluated against Gram-positive Staphylococus aureus bacteria and Gram-negative Pseudomonas aeruginosa bacteria by the well diffusion method. The SnO2: Mg: Co nanopowders exhibit superior photocatalytic activity when compared with pristine SnO2. The degradation process follows a pseudo-first-order kinetics. The rate constant of SnO2: Mg: Co nanopowder is 1·2 times greater than that of pristine SnO2 nanopowder for the degradation of MB dye while for MG dye degradation, it is 1·5 times. Moreover, antibacterial activity of SnO2: Mg: Co nanopowder showed better antibacterial properties compared to pristine SnO2. The above mentioned samples were synthesised using a simple and low-cost soft chemical process.