Wet Chemical Approach Research Articles

Synthesis of Pectin and Eggshell Biowaste-Mediated Nano-hydroxyapatite (nHAp), Their Physicochemical Characterizations, and Use as Antibacterial Material.

The current study reports the synthesis of sustainable nano-hydroxyapatite (nHAp) using a wet chemical precipitation approach. The materials used in the green synthesis of nHAp were obtained from environmental biowastes such as HAp from eggshells and pectin from banana peels. The physicochemical characterization of obtained nHAp was carried out using different techniques. For instance, X-ray diffractometer (XRD) and FTIR spectroscopy were used to study the crystallinity and synthesis of nHAp respectively. In addition, the morphology and elemental composition of nHAP were studied using FESEM equipped with EDX. HRTEM showed the internal structure of nHAP and calculated its grain size which was 64 nm. Furthermore, the prepared nHAp was explored for its antibacterial and antibiofilm activity which has received less attention previously. The obtained results showed the potential of pectin-bound nHAp as an antibacterial agent for various biomedical and healthcare applications.

A Novel Time-Saving Synthesis Approach for Li-Argyrodite Superionic Conductor.

The wet-chemical synthetic approach for Li-argyrodite superionic conductors for all-solid-state batteries (ASSBs) is promising as it saves time, energy, and cost, while achieving scalable production. However, it faces certain commercialization issues such as byproduct generation, nucleophilic attack of the solvent, and long processing times. In this study, a facile and time-saving microwave-assisted wet synthesis (MW-process) approach is proposed for Li6 PS5 Cl (LPSC), which is completed in 3h at the precursor-synthesis stage. The LPSC crystal obtained from the MW-process presents various advantages such as fast-PS4 3- generation, high solubility of LiCl, and low adverse effects from solvent molecules. These features help in achieving a high Li-ion conductivity (2.79 mS cm-1 ) and low electric conductivity (1.85×10-6 mS cm-1 ). Furthermore, the LPSC crystal is stable when reacting with Li metal (2000h at 0.1mA cm-2 ) and exhibits superior cyclability with LiNi0.6 Co0.2 Mn0.2 (NCM622) (145.5mA h g-1 at 0.5 C, 200 cycles with 0.12% of capacity loss per cycle). The proposed synthetic approach presents new insights into wet-chemical engineering for sulfide-based solid-electrolytes (SEs), which is crucial for developing ASSBs from a commercial-scale perspective.

Fast and Durable Dehydrogenation of Formic Acid over Pd–Cr(OH)3 Nanoclusters Immobilized on Amino-Modified Reduced Graphene Oxide

Formic acid, attractive as a renewable and safe liquid organic hydrogen carrier (LOHC), can be obtained by biomass conversion and CO2 hydrogenation with green hydrogen. The efficient and durable catalysts for formic acid dehydrogenation (FAD) are beneficial in the industry. Herein, Cr(OH)3-promoted Pd nanoclusters (NCs) (i.e., 1.6 nm) immobilized on amino-modified reduced graphene oxide (NH2-rGO) were successfully prepared through a simple wet-chemical approach. The obtained Pd–Cr(OH)3/NH2-rGO catalyst exhibits excellent catalytic activity and 100% hydrogen selectivity for CO-free FAD, giving a high turnover frequency of 2519.5 h–1 at 323 K, outperforming most reported Pd-based heterogeneous catalysts. Especially, the catalyst possesses robust durability toward FAD with no significant decline in activity and aggregation of metal NCs even after 10 cycles. The superior performance of the catalyst may be ascribed to the well-distributed Pd–Cr(OH)3 NCs, the strong electronic coupling of Pd with Cr(OH)3, the synergetic interaction of Pd–Cr(OH)3 with NH2-rGO, and the promotion effect of amino group. The reaction mechanism of FAD was explored based on the isotope experiments. This work provides insights into designing an effective and durable heterogeneous catalyst for dehydrogenation of LOHC.

Modular Attachment of Nanoparticles on Microparticle Supports via Multifunctional Polymers.

Nanoparticles are key to a range of applications, due to the properties that emerge as a result of their small size. However, their size also presents challenges to their processing and use, especially in relation to their immobilization on solid supports without losing their favorable functionalities. Here, we present a multifunctional polymer-bridge-based approach to attach a range of presynthesized nanoparticles onto microparticle supports. We demonstrate the attachment of mixtures of different types of metal-oxide nanoparticles, as well as metal-oxide nanoparticles modified with standard wet chemistry approaches. We then show that our method can also create composite films of metal and metal-oxide nanoparticles by exploiting different chemistries simultaneously. We finally apply our approach to the synthesis of designer microswimmers with decoupled mechanisms of steering (magnetic) and propulsion (light) via asymmetric nanoparticle binding, aka Toposelective Nanoparticle Attachment. We envision that this ability to freely mix available nanoparticles to produce composite films will help bridge the fields of catalysis, nanochemistry, and active matter toward new materials and applications.

Bifunctional electrocatalytic water splitting augmented by cobalt-nickel-ferrite NPs-supported fluoride-free MXene as a novel electrocatalyst

Electrocatalytic water splitting is a promising approach for the massive production of hydrogen as an environmentally compatible and renewable energy alternative to fossil fuels. The development of an active, stable, low-cost, and bifunctional electrocatalyst, in this regard, is a big challenge to achieve the desired electrocatalytic hydrogen/oxygen production via water splitting. MXene (Ti3C2Tx) has recently been explored as an excellent candidate for electrocatalytic water splitting. However, its poor stability, hazardous synthesis routes, and the restacking of its flakes are the major bottlenecks in its effective application as an electrocatalyst. Herein, we adopted an acid-free wet chemical approach to synthesize MXene and its composites with CoNiFe2O4 for efficient water splitting. We proposed a novel layer-by-layer (LBL) assembly approach to obtain a CoNiFe2O4/MXene-based 2D/NPs/2D network and prevented restacking in MXene flakes for efficient electrocatalysis. The inserted NPs via the LBL approach engaged the delaminated MXene flakes, which results in a high surface area and active sites for water splitting. The fabricated catalyst showed excellent overpotentials of 149 and 17 mV at 10 mA/cm2 for water splitting via OER and HER. In addition, the Tafel slope of 36 and 45 mV/dec was achieved for HER and OER along with high electrochemical stability upto 100 h, which surpassed many similar catalysts that were recently reported in the literature. This study provides insights into the design of multicomponent low-dimensionalelectrocatalysts for water splitting.

An investigation on the structural and optical properties of mercaptosuccinic acid capped cadmium telluride quantum dots

In this work, a sonication induced modified wet chemical approach is adopted to synthesize highly luminescent and water soluble cadmium telluride (CdTe) quantum dots (QDs). The morphology, size, crystal structural, and optical properties of CdTe QDs are investigated for different refluxing time (1–4 h). The refluxing time-dependent optical constants viz. band gap energy and Urbach energy of the QDs are estimated from UV–Visible absorption spectra. The optical band gap energy decreased from ~ 2.12 to 1.92 eV and the Urbach energy increased from ~ 361 to 487 meV, with the increase in refluxing time. CdTe QDs are found to be uniform in size. The average size of the QDs estimated from the High Resolution Transmission Electron Microscope image analysis is about 5.8 and 8.2 nm for refluxing times 1 and 4 h, respectively. The growth mechanism of the QDs as a function of refluxing time has also been discussed. The fluorescence spectra of the QDs, revealed emission peaks having wavelength from ~ 534 to 585 nm, under the excitation wavelength of 320 nm. The fluorescence emission peaks showed a bathochromic shift with increasing refluxing time. CdTe QDs also exhibit excitation-dependent fluorescence behaviour. Two crystalline phases of the CdTe QDs, namely hexagonal and cubic are confirmed from the High Resolution Transmission Electron Microscope images and Selected Area Electron Diffraction patterns analysis. The phase transformation from hexagonal to cubic is successfully achieved by tuning the refluxing time from 1 to 4 h.

New Insights into Cu/Cu2O/CuO Nanocomposite Heterojunction Facilitating Photocatalytic Generation of Green Fuel and Detoxification of Organic Pollutants

Cu/Cu2O/CuO nanocomposites were synthesized using the simple wet chemical approach for the production of dihydrogen as a potential fuel source and for the detoxification of dyes. The formation of Cu/Cu2O/CuO nanocomposites is confirmed by powder X-ray diffraction, whereas the W-H plot revealed the average particle size of nanocomposite approximately 17 nm, which is in good agreement with the Scherrer method and transmission electron microscopy analysis. The uniform distribution of Cu and O elements was supported by the elemental mapping of the nanocomposite. Band gaps of CuO and Cu2O were found to be 1.71 and 1.92 eV, respectively, using diffuse reflectance spectroscopy spectra and Kubelka–Munk functions. The oxygen vacancies in the nanocomposite are confirmed by various analytical spectroscopic techniques, such as electron paramagnetic resonance, Raman, photoluminescence, and X-ray photoelectron spectroscopy (XPS) spectra. The significant boost in the performance of the fabricated nanocomposite was observed and is attributed to the formation of a heterojunction and existence of oxygen vacancy. The nanocomposite demonstrated proficiency in the photocatalytic splitting of water for the production of hydrogen. The maximum hydrogen generation yield (68 μmol g–1) was observed for Cu/Cu2O/CuO nanocomposites along with NiO (co-catalyst) and methanol as a hole scavenger as well as an electron donor. Moreover, the degradation of congo red (CR) and malachite green (MG) dyes was also investigated and the efficiency of the nanocomposite was found to be 80 and 60%, respectively, after 120 min of light irradiation. The stability of nanocomposites after photocatalysis was investigated by the XPS spectrum of the nanocomposite. Explicitly, the area and broadening of the O 1s XPS spectrum demonstrated higher degradation of CR dye as compared to MG dye.

Plasma surface functionalization: A comprehensive review of advances in the quest for bioinstructive materials and interfaces

Surface biofunctionalization aims to create cell-instructive surfaces that control the behavior of cells and modulate cellular interactions by incorporating cell signaling moieties at the materials–biosystem interface. Despite advances in developing bioinert and biocompatible materials, blood clotting, inflammation, and cell death continue to be observed upon the contact of foreign materials with living tissues leading to the materials' rejection. Specific examples include the application of foreign materials in implantable devices (e.g., bone implants, antimicrobial surfaces, and cardiovascular stents), biosensors, drug delivery, and 3D-bioprinting. Biofunctionalization of materials to date has been predominantly realized using wet chemical approaches. However, the complexity of wet chemistry, toxicity of reactants, waste disposal issues, reaction time, poor reproducibility, and scalability drive a need for a paradigm shift from wet chemical approaches to dry methods of surface biofunctionalization. Plasma-based technologies that enable covalent surface immobilization of biomolecules have emerged as dry, reagent-free, and single-step alternatives for surface biofunctionalization. This review commences by highlighting the need for bioinstructive surfaces and coatings for various biomedical applications such as bone implants, antimicrobial surfaces, biosensors, and 3D-bioprinted structures, followed by a brief review of wet chemical approaches for developing biofunctionalized surfaces and biomimetic devices. We then provide a comprehensive review of the development of plasma-based technologies for biofunctionalization, highlighting the plasma–surface interactions and underpinning mechanisms of biomolecule immobilization.

Promoting progress in plasma surface biofunctionalization

Emerging technologies could enable shift from wet chemical approaches for biomedical applications

The Role of Silver Nanoparticles in Electrochemical Sensors for Aquatic Environmental Analysis

With rapidly increasing environmental pollution, there is an urgent need for the development of fast, low-cost, and effective sensing devices for the detection of various organic and inorganic substances. Silver nanoparticles (AgNPs) are well known for their superior optoelectronic and physicochemical properties, and have, therefore, attracted a great deal of interest in the sensor arena. The introduction of AgNPs onto the surface of two-dimensional (2D) structures, incorporation into conductive polymers, or within three-dimensional (3D) nanohybrid architectures is a common strategy to fabricate novel platforms with improved chemical and physical properties for analyte sensing. In the first section of this review, the main wet chemical reduction approaches for the successful synthesis of functional AgNPs for electrochemical sensing applications are discussed. Then, a brief section on the sensing principles of voltammetric and amperometric sensors is given. The current utilization of silver nanoparticles and silver-based composite nanomaterials for the fabrication of voltammetric and amperometric sensors as novel platforms for the detection of environmental pollutants in water matrices is summarized. Finally, the current challenges and future directions for the nanosilver-based electrochemical sensing of environmental pollutants are outlined.

Confined Bismuth-Organic Framework Anode for High-Energy Potassium-Ion Batteries.

Metal-organic frameworks (MOFs) with inherent porosity, controllable structures, and designable components are recognized as attractive platforms for designing advanced electrodes of high-performance potassium-ion batteries (PIBs). However, the poor electrical conductivity and low theoretical capacity of many MOFs lead to inferior electrochemical performance. Herein, for the first time, a confined bismuth-organic framework with 3D porous matrix structure (Bi-MOF) as anode for PIBs via a facile wet-chemical approach is reported. Such a porous structure design with double active centers can simultaneously ensure the structure integrity and efficient charge transport to enable high-capacity electrode with super cycling life. As a result, the Bi-MOF for PIBs exhibits high reversible capacity (419 mAh g-1 at 0.1 A g-1 ), outstanding cycling stability (315 mAh g-1 at 0.5 A g-1 after 1200 cycles), and excellent full battery performance (a high energy density of 183Wh kg-1 is achieved, outperforming all reported metal-based anodes for PIBs). Moreover, the K+ storage mechanisms of the Bi-MOF are further unveiled by in situ Raman, ex situ high-resolution transmission electron microscopy, and ex situ Fourier-transform infrared spectroscopy. This ingenious electrode design may provide further guidance for the application of MOF in energy storage systems.

Silver doped MnCo2O4 spinel mixed oxides with rGO nanocomposites for the photocatalytic and antibacterial studies

Silver doped manganese cobalt spinel mixed oxides (Ag/MnCo2O4) were synthesized through solvent free wet chemical approach. As-synthesized Ag/MnCo2O4 nanoparticles were embedded with reduced graphene oxide nanosheets (rGO) to synthesize Ag/MnCo2O4/rGO nanocomposite. Different techniques (XRD, FTIR, SEM and UV/VIS) were carried out to study structural and morphological properties. XRD analysis determined cubic face centered structure of synthesized MnCo2O4, Ag/MnCo2O4 and Ag/MnCo2O4/rGO nanocomposite. Methylene blue was used as organic pollutant to investigate photocatalytic test. Degradation percentages for MnCo2O4, Ag/MnCo2O4 and Ag/MnCo2O4/rGO nanocomposite were determined 43.24%, 50% and 84.3% respectively. Ag/MnCo2O4/rGO nanocomposite showed highest degradation efficiency under sunlight.

In Vitro Acaricidal Activity of Silver Nanoparticles (AgNPs) against the Poultry Red Mite (Dermanyssus gallinae)

Dermanyssus gallinae (PRM) is the most common blood-sucking ectoparasite in laying hens and is resistant against numerous acaricides. Silver nanoparticles (AgNPs) represent an innovative solution against PRM. The current study aimed to assess the in vitro acaricidal activity of AgNPs against PRM and describe their potential mechanism of action. Nanoparticles were produced using a wet chemistry approach. Mites were collected using AviVet traps from 18 poultry farms in Greece. Contact toxicity bioassays were carried out for 24 h with negative controls, 20, 40, 60, or 80 ppm AgNPs. Analysis of variance was used to compare the mortality rates of PRM between the control and treatment groups, while LC50, LC90, and LC99 values were estimated using probit regression analysis for the total farms jointly and separately. Nanoparticles displayed strong acaricidal activity, and mortality rates were significantly different between groups and increased by AgNPs concentration. Overall mean LC50, LC90, and LC99 values were 26.5, 58.8, and 112.3 ppm, respectively. Scanning electron microscopy on mites treated with 80 ppm AgNPs revealed cracks in their exoskeleton and limb detachments, presumably resulting from the interaction between AgNPs and the mites' chitin. Future studies should focus on assessing AgNPs residues in chicken tissues before moving into field trials.

Removal of secondary phases and its effect on the transport behavior of Cu2ZnSn1-xGexS4 kesterite nanoparticles

Hole-transporting materials are very important for achieving high efficiency in perovskite solar cells. Thin films made of Cu2ZnSn1-xGexS4 have attracted the attention of researchers due to their potential as hole-transporting layers. However, defects and impurities define their effectiveness in solar cells. In this work, we present a facile wet chemical approach to remove the ZnS and Cu8GeS6 impurities from small (∼11 nm) Cu2ZnSn1-xGexS4 (x = 0.0 to 0.7) nanoparticles synthesized by a hydrothermal process. The wet chemical process converted the nanostructures Cu-rich Zn-poor from their initial Zn-rich Cu-poor stoichiometry. Moreover, the bandgap energies of the nanostructures were reduced by about 0.1 eV after chemical treatment due to change the oxidation state of Cu from Cu1+ to Cu2+. The kesterite films prepared by spin coating of chemically treated nanoparticle inks revealed enhanced electrical conductivity and hole concentration in comparison to the films prepared using untreated nanoparticle inks. While the highest hole concentration of about 6.52x1018 cm−3 was obtained for the films made of Cu2ZnSn1-xGexS4 nanoparticles with the highest x value (x = 0.7), the highest hole mobility (18.9 cm2V−1s−1) was achieved for x = 0.3. The effects of secondary phase elimination on carrier concentration and mobility variation have been discussed.

Investigation of calcium substitution on magnetic and dielectric properties of Mg–Zn nano ferrites

In this work, an efficient, cost-effective, and less time-consuming citrate precursor wet chemical approach was employed to prepare a series of Calcium (Ca) doped Magnesium–Zinc ferrite of composition Mg0.4Zn0.6-xCax Fe2O4 (0.0 ≤ x ≤ 0.6). X-ray diffraction (XRD), Scanning electron microscopy (SEM) with Energy dispersive X-ray (EDX) analysis confirmed the spinel structure and nanometric size of the particles. Williamson-Hall (W–H) plots were drawn by making use of XRD data and calculated values of lattice strain were found in the range (3.00 × 10−3 to 9.09 × 10−3) for various concentrations of calcium. The cubic spinel structure of produced ferrites was also verified by three active Raman modes (A1g, Eg, and T2g). In the Vibrating sample magnetometer (VSM) study, an “S” shape curve shows the low values of coercivity for all the samples in the range 59–105 Oe. For all Ca concentrations, the dielectric loss tangent values were evaluated to be extremely low 0.03 to 0.18 at 1 MHz frequency. The highly magnetic nature and very low value of loss factor make this prepared nanoferrite material best suited for the manufacturing of high-frequency application devices.

Synergy of phosphate recovery from sludge-incinerated ash and coagulant production by desalinated brine

Wet-chemical approach is widely applied for phosphate recovery from incinerated ash of waste activated sludge (WAS), along with metals removed/recovered. The high contents of both aluminum (Al) and iron (Fe) in WAS-incinerated ash should be suitable for producing coagulants with some waste anions like Cl− and SO42− With acid (HCl) leaching and metals’ removing, approximately 88 wt% of phosphorus (P) in the ash could be recovered as hydroxylapatite (HAP: Ca5(PO4)3OH); Fe3+ in the acidic leachate could be selectively removed/recovered by extraction with an organic solvent of tributyl phosphate (TBP), and thus a FeCl3-based coagulant could be synthesized by stripping the raffinate with the original brine (containing abundant Cl− and SO42−). Furthermore, a liquid poly-aluminum chloride (PAC)-based coagulant could also be synthesized with Al3+ removed from the ash and the brine, which behaved almost the same in the coagulation performance as a commercial coagulant on both phosphate and turbidity removals. Both P-recovery from the ash and coagulant production associated with the brine would enlarge the markets of both ‘blue’ phosphate and ‘green’ coagulants.

UV‐blocking performance and antibacterial activity of Cd, Ba co‐doped ZnO nanomaterials prepared by a facile wet chemical method

The utilization of highly efficient ultraviolet (UV)‐attenuating materials has inevitably signaled an ever‐increasing demand to mitigate the impending pessimistic impact of UV rays that consistently depletes the ozone atmosphere. In this context, a highly efficient Cd, Ba co‐doped ZnO nanomaterial has been prepared using a facile wet chemical approach. X‐ray diffractometer analysis indicates the evolution of wurtzite structure of ZnO with a slight peak shift towards the higher angle upon co‐doping which ascertains the impacted lattice contraction. N2 adsorption/desorption isotherms of the material supplement magnificently a typical type‐IV behavior displaying an H1 type hysteresis loop at high pressures whereby authorizing the open meso‐porous characteristics. The resulting Cd, Ba co‐doped ZnO nanorods disclose integrated performances of widespread polychromatic UV–visible luminescent emission, wide band gap, and enhanced UV absorbance. In particular, Cd, Ba co‐doped ZnO nanorods impart a positive UV‐blocking execution of 97% for UVA at 360 nm and 88% for UVB at 320 nm, which is found to be higher than most of the reported ZnO‐related materials. Besides these intriguing aforementioned properties, co‐doping is also appropriate for imparting better bacterial inhibition against the two tested strains (Escherichia coli and Staphylococcus aureus). Altogether, these results indicate that the co‐doped ZnO nanorods developed in the current investigation could potentially serve as a propitious alternative UV‐blocking material, especially for biomedical applications.

A Z-scheme BiYO3/g-C3N4 heterojunction photocatalyst for the degradation of organic pollutants under visible light irradiation.

Photocatalysis is one of the fascinating fields for the wastewater treatment. In this regard, the present study deals with an effective visible light active BiYO3/g-C3N4 heterojunction nanocomposite photocatalyst with various ratios of BiYO3 and g-C3N4 (1:3, 1:1 and 3:1), synthesised by a wet chemical approach. The as-synthesised nanocomposite photocatalysts were investigated via different physicochemical approaches like Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electrons microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and photoelectrochemical studies to characterise the crystal structure, morphology, optical absorption characteristics and photoelectrochemical properties. The photocatalytic degradation ability of the prepared photocatalytic samples was also analysed through the degradation of RhB in the presence of visible light irradiation. Of all the synthesised photocatalysts, the optimised CB-1 composite showed a significant photocatalytic efficiency (88.7%), with excellent stability and recyclability after three cycles. O2•- and •OH radicals were found to act a major role in the RhB degradation using optimised CB-1 composite, and it possessed ~ 1 times greater photocurrent intensity than the pristine g-C3N4 and BiYO3. In the present work, a direct Z-scheme heterojunction BiYO3/g-C3N4 with a considerably improved photocatalytic performance is reported.

Orange Peel Biomass-derived Carbon Supported Cu Electrocatalysts Active in the CO2 -Reduction to Formic Acid.

We report a green, wet chemistry approach towards the production of C-supported Cu electrocatalysts active in the CO2 reduction to formic acid. We use citrus peels as a C support precursor and as a source of reducing agents for the Cu cations. We show that orange peel is a suitable starting material compared to lemon peel for the one-pot hydrothermal synthesis of Cu nanostructures affording better Cu dispersion as well as productivity and selectivity towards formic acid. We rationalize this finding in terms of the beneficial chemical composition of the orange peel, which favors both the reduction of the Cu precursor as well as the carbon matrix. This work demonstrates new viable opportunities for the reuse of citrus waste on a rational basis.

Facile synthesis of a multifunctional ternary SnO2/MWCNTs/PANI nanocomposite: Detailed analysis of dielectric, electrochemical, and water splitting applications

Herein, a SnO2/MWCNTs/PANI nanocomposite was synthesized using a wet chemical approach which acts as a multifunctional electrode for supercapacitor and hydrogen evolution reaction. The dielectric properties were studied using the Maxwell-Wagner model of space charge polarization. The increasing dielectric constant indicated the suitability of synthesized NPs for telecommunication, electronics, and other high-frequency applications. The dependence of impedance and dielectric behavior on grains and grain boundaries was further investigated via impedance spectroscopy and complex electric modulus. Based on a 6 M KOH aqueous electrolyte, the SnO2/MWCNTs/PANI as an electrode material for supercapacitors displays a capacity of 211 C g−1 at 1 A g−1 and exhibits excellent cycling stability with a capacitance retention ratio of 98% after 5000 cycles at a current density of 2 A g−1. For hydrogen evolution reaction in 0.5 M KOH, SnO2/MWCNTs/PANI electrode achieves a benchmark of 10 mA cm−2 at overpotentials of 524 mV. The results reveal that the SnO2/MWCNTs/PANI nanocomposite act as multifunctional material that can be used for both energy storage and conversion.