UV Diffuse Reflectance Spectroscopy Research Articles

Influence of PVP on the properties of solvothermally synthesized famatinite nanoparticles: Structural, morphological and optical insights

Famatinite (Cu3SbS4) nanoparticles were synthesized through a solvothermal approach using various polyvinylpyrrolidone (PVP) ratios as a capping agent with a binary solvent of ethylene glycol and water in equal parts. Incremental additions of PVP, ranging from 0 to 1.5 g, exerted significant influence on the material's characteristics. Through comprehensive analysis involving X-ray diffraction, Raman spectroscopy, Scanning electron microscopy (SEM) with Energy dispersive spectrometer (EDS), and UV diffuse reflectance spectroscopy, critical insights were obtained. XRD analysis confirmed the tetragonal crystal structure and revealed reduced crystallite sizes due to the incorporation of PVP. Raman spectroscopy validated the presence of pure famatinite phase with 0.5 g and 1.0 g PVP. SEM analysis uniformly depicted a spherical morphology in all samples, emphasizing PVP's role in mitigating nanoparticle agglomeration. UV diffuse reflectance spectroscopy disclosed direct bandgaps falling within the 0.88 – 0.97 eV range. The collective findings highlighted the substantial impact of PVP in the binary solvent on the structural, morphological, and optical properties of Cu3SbS4 nanoparticles. These results underscore the potential application of these tailored nanoparticles as promising candidates for advanced photovoltaic absorber materials.

Hollow cubic TiO2 loaded with copper and gold nanoparticles for photocatalytic CO2 reduction

A simple photodeposition method is used to prepare Cu and Au nanoparticles modified TiO2 nanocomposites. The phase composition of the catalyst is determined by x-ray diffraction. The mutual synergistic effects of Cu and Au are analyzed using x-ray photoelectron spectroscopy, photoluminescence spectroscopy and UV diffuse reflectance spectroscopy. The results indicate that the TiO2 is anatase structure with hollow cubic morphology, which enhances the utilization of visible light and improves the photocatalytic performance compared with P25. The Cu0.7Au0.3/TiO2 has the highest carrier separation efficiency and the best photocatalytic performance with a CO yield of 6.08 umol g−1 h−1, which is about four times higher than that of TiO2 (1.56 umol g−1 h−1). The aforementioned results indicate that the photocatalytic activity for CO2 reduction is greatly enhanced by the addition of modest quantities of Cu and Au NPs. During the photocatalytic process, the presence of Au NPs absorbs visible light and modulates the surface structure of electrons, while Cu serves as an electron sink, hence promoting efficient separation of electron-hole pairs. Utilizing the distinct benefits of bimetal and their robust interactions is a viable and efficacious approach for boosting the photocatalytic activity.

Multifunctional CoFe2O4/ZnO nanocomposites: probing magnetic and photocatalytic properties

Developing nanocomposites as efficient photocatalysts for eliminating hazardous contaminants is essential because of growing severity of water pollution. In this study, we have analysed the morphological, structural, magnetic, and optical properties of cobalt ferrite (CoFe2O4), and zinc oxide (ZnO) nanocomposites synthesized via hydrothermal approach and used for removal of rose bengal (RB) dye from contaminated water. X-ray diffraction (XRD) analysis of synthesized nanocomposite revealed two distinct phases that matched with CoFe2O4 and ZnO. Fourier transform infrared (FTIR) spectra enlightened Co–O, Fe–O, and O–Zn–O binding peaks in synthesized nanocomposites. The band gap of nanocomposite, as determined by UV diffuse reflectance spectroscopy (UV-DRS), varies from 1.53 to 3.29 eV. The wide band gap semiconductor (ZnO) is believed to be responsible for this transformation by introducing new sub-bandgap energy levels. X-ray photoelectron spectroscopy has shown the roles of various ions. High-resolution transmission electron microscopy analysis revealed spherical morphology of synthesized samples. The highest magnetism of pure CoFe2O4 was 34.6 emu g−1, making it the most magnetic among all the synthesized materials. Furthermore, CoFe2O4/ZnO (1:4) nanocomposite exhibited the highest degradation of RB dye. The recombination of electron-hole pairs is inhibited by interfacial charge transfer provided by CoFe2O4 and ZnO. The results showed that CoFeZn14 nanocomposite is a promising candidate for wastewater treatment. CoFeZn14 demonstrated remarkable stability, showcasing its ability to be reused up to four times without compromising its efficiency.

Hybrid calcium magnesium ferrite: A multifaceted nanomaterial for energy, sensing, and environmental applications

The current work employs the urea aided conventional sol–gel procedure to synthesize hybrid calcium magnesium ferrite (CMF – CaO/MgFe2O4) nanomaterial. To verify the existence of synthesized nanomaterials, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and UV diffuse reflectance spectroscopy (UV-DRS) are employed. The observed crystalline size of the nanomaterials is 44.14 nm. The estimated band gap is 2.36 eV, which is validated using UV-DRS equipment. The investigation's findings are supported by actual applications in electrochemical studies and photocatalytic degradation of synthesized hybrid CMF. It was also investigated how to modify the working electrode's surface to detect heavy metals, drugs, and biomolecules like uric acid, paracetamol, creatinine, cadmium and mercury. Electrochemical research was done to determine the ideal properties of CMF as an electrode material for use in batteries, supercapacitors, and sensors applications. Furthermore, synthesized hybrid CMF exhibits excellent photocatalytic activity, employed as a catalyst to decolorize acid red 88(AR-88) dyes at room temperature under visible light illumination, with a 120-minute photocatalytic activity with the degradation efficiencyof 60.40 %.

Ag-loaded BiFeO3/CuS heterostructured based composite: an efficient photocatalyst for removal of antibiotics and antibacterial activities.

The performance of advanced materials in environmental applications using green energy is the tremendous interest among researchers. The visible light responsive BiFeO3 (BFO), BiFeO3/CuS (BFOC), and Ag-loaded BiFeO3/CuS (Ag-BFOC) heterostructures have been synthesized by reflux method followed by hydrothermal and wetness impregnation method. These synthesized composites are well characterized through X-ray diffraction, UV diffuse reflectance spectroscopy, scanning electron microscope, and Fourier transfer infrared spectroscopy techniques. Compared with BFO and BFOC, Ag-BFOC exhibits the highest photocatalytic performance towards the degradation of antibiotics ciprofloxacin (76%) within 120-min time and also showed better antibacterial performance towards gram-negative (Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii) bacteria. Moreover, the novelty of the present work is the addition of CuS on the surface of BiFeO3 from heterojunction type II and facilitates the electron-hole channelization at the interfaces between BiFeO3 and CuS. Again, the loading of Ag on BiFeO3/CuS helps in shifting the absorption band towards the red end, is eligible to absorb more sunlight due to surface plasmon resonance effect, improves the separation efficiency of photo-generated charge carriers, and enhances the photocatalytic degradation of ciprofloxacin. The antibacterial property of Ag gives a best result towards antimicrobial activity. The prepared composites have proved their durability and stability by four successive cycles and prove the versatility of the composite.

Assessment of solar light sensitive Chitosan integrated CeO2-CuO ternary composites for the efficient degradation of Malachite Green, Acid Blue 113 dyes and microbial studies

Ternary chitosan integrated CeO2-CuO composites were prepared via a facile co-precipitation technique and thoroughly characterized using FTIR spectroscopy, X-ray diffraction, UV-diffuse reflectance spectroscopy, Thermo gravimetric analysis, Scanning emission microscopy, Transmission electron microscopy and X-ray Photoelectron spectroscopy. The composite with 10 wt% CeO2-CuO on chitosan exhibited the highest efficiency of 92 % and 91 % in degrading malachite green (MG) and acid blue 113 (AB 113) respectively. This composite demonstrated efficient generation of electron-hole pairs, minimized recombination rates and facilitated rapid dye degradation under solar light illumination. Additionally, the composites displayed effective antibacterial activity against Serratia marcescens and Bacillus subtilis at a concentration of 100 µl, and exhibited promising anti-fungal activities against Candida albicans and Aspergillus niger. These findings suggest the potential of these composites for efficient dye degradation and demonstrate their promising antimicrobial properties, offering possibilities for diverse environmental and biomedical applications.

A Comparative Study of Green and Chemical Approaches for Photocatalytic Activity of Novel Hybrid Bismuth Magnesium Ferrites (BiMgFe2O4) Nanoparticles for Acid Red-88 Dye Degradation

Uncontrolled release of several dangerous pollutants had negatively impacted the environment causing water pollution and retarded plant growth. Recently, nanoferrites utilized as photocatalyst to eliminate water pollutants. The benefitsofhybrid photocatalyst have significantly improved separating and charge transfer capabilities. In the present investigation novel bismuth magnesium ferrites (BMF - BiMgFe2O4) are synthesized via conventional solution combustion method using green and chemical approach. The particles are confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM),Energy disperse X-ray diffraction analysis (EDX), UV-DRS (UV diffuse reflectance spectroscopy). The observed crystalline size for the nanoparticles synthesized by green and chemical approach is 25.15 nm and 18.55 nm respectively. Analyzed band gap observed is 2.89 eV and 1.98 eV for green and chemical approach that are confirmed by employing UV-DRS technique. The outcomes obtained from studies are verified with capable applications in photocatalytic degradation. The application of BiMgFe2O4 as catalyst for decolourisation of acid red 88 (AR-88) dyes under visible irradiation at room temperature exhibits superior photocatalytic activity for BiMgFe2O4 is 74.22% and 85.27% using green and chemical approach for 120 minutes respectively. It's significant that the environmental impact of the whole procedure has been assessed with regard to the development of green gramplants utilizing the treated wastewater exhibiting effective plant growth. The overall feasibility of the research presented here provides the opportunity to apply chemically synthesized BMF acts as superior photocatalyst for pollutants from particles in practical applications related to wastewater treatment and other applications in daily life. Using degradedwater yields productive plant growth.

ZIF-8 incorporated CeO2-CdS quantum dots @ 2D g-C3N4 nanosheets as a staggered type II heterojunction for decolouration of a set of dyes

Dye toxins, emitted by industries, pose a significant threat to living beings and aquatic life by absorbing light radiation and inhibiting the growth of essential bacteria and microbes, making their removal crucial for health of living beings and flora and fauna. This research endorsed a hydrothermal synthetic route for the photocatalyst CeO2/CdS/g-C3N4 @ZIF8 (or CCdGZ) fabrication to remove a set of hazardous dyes from wastewater streams. Corresponding Analytical methods evaluated the successfully developed CCdGZ photocatalyst's structural, morphological, and compositional properties. Powder X-ray photoelectron (PXRD) analysis showed the structural properties of CCdGZ and the quantum dot nature of the CeO2-CdS hybrid in the heterostructure with a crystallite size of 0.16 nm. The photocatalyst's optical responses were examined using UV–vis spectrophotometry and the UV-diffuse reflectance spectroscopy (UV-DRS) technique. Tauc's plot determined the energy band gap of the CCdGZ to be ∼2.64 eV, confirming a slight modification of the valence band (VB) and conduction band (CB) edges of the moieties CeO2, CdS, and g-C3N4. Thus, the heterostructure's moieties synergised to produce photocatalytic degradation. Under visible light irradiation, the photocatalyst CCdGZ photodegraded Victoria blue R (VBR) dye by 96.54% in 55 min. Photodegradation followed pseudo-first-order kinetics with a specific reaction rate of 0.06159 min−1 {coefficient of determination (R2) = 0.99847}. The corresponding TOC removal was 83.27%, while COD got reduced to 78.98% of its initial magnitude. Multiple reaction parameters, heterostructure reusability (over 89% efficient till the 5th run), the scavengers' experiment, inorganic ion effects, and water matrices were also evaluated. The study concludes with a photocatalytic reaction mechanism that explains the moieties' roles. This study designs a heterostructure photocatalyst that disintegrates emerging non-degradable organic pollutants in the UV–visible range, is recoverable, and has better photostability.

Synthesis and Luminescent Properties of Barium Molybdate Nanoparticles.

BaMoO4 was obtained via facile mechanochemical synthesis at room temperature and a solid-state reaction. An evaluation of the phase composition and structural and optical properties of BaMoO4 was conducted. The influence of different milling speeds on the preparation of BaMoO4 was explored. A shorter reaction time for the phase formation of BaMoO4 was achieved using a milling speed of 850 rpm. A milling speed of 500 rpm led to partial amorphization of the initial reagents and to prolongation of the synthesis time of up to 3 h of milling time. Solid-state synthesis was performed via heat treatment at 900 °C for 15 h. X-ray diffraction analysis (XRD), infrared (IR) and UV diffuse reflectance (UV-Vis) and photoluminescence (PL) spectroscopy were carried out to characterize the samples. Independently of the method of preparation, the obtained samples had tetragonal symmetry. The average crystallite sizes of all samples, calculated using Scherrer's formula, were in the range of 240 to 1540 Å. IR spectroscopy showed that more distorted structural MoO4 units were formed when the compound was synthesized via a solid-state reaction. The optical band gap energy of the obtained materials was found to decrease from 4.50 to 4.30 eV with increasing crystallite sizes. Green- and blue-light emissions were observed for BaMoO4 phases under excitation wavelengths of 330 and 488 nm. It was established that the intensity of the PL peaks depends on two factors: the symmetry of MoO4 units and the crystallite sizes.

Efficient photocatalytic degradation of water pollutant Brufen using lutetium doped cerium oxide nanoparticles synthesized by chemical precipitation method

BackgroundPlants act the foremost source of molecules for the advancement of new drugs regarding anti-inflammatory action. In recent years, pharmaceutical compounds have been categorized as the emerging pollutants and have grabbed the attention of the researchers due to their existence in wastewater. They have been detected in drinking water which shows that the wastewater treatment plants are always not efficacious. These contaminants are pernicious if present in higher dosage and cause several risk factors to humans, animals, and aquatic systems. Ibuprofen, one of the most prescribed analgesics found to cause severe damage to stomach and intestine has been subjected to photocatalytic degradation using Lutetium doped Cerium oxide nanoparticles. The nanoparticles were synthesized using chemical precipitation method which is cost effective, simple, and ecofriendly. MethodsThe synthesized nanomaterial was characterized and confirmed using several analytical techniques like X-Ray Diffraction studies (XRD), Fourier Transform-Infrared Spectroscopy (FT-IR), UV-Diffuse Reflectance Spectroscopy (UV-DRS), High Resolution Scanning Electron Microscopy (HRSEM), X-Ray energy dispersive spectroscopy (EDAX), High Resolution Transmission Electron Microscopy (HRTEM), and X-ray Photoelectron Spectroscopy (XPS). Significant findingsXRD data revealed the cubic shape of the nanoparticles with approximate size of 6–12 nm. FT-IR study confirmed the presence of metal oxide peak at 550 cm−1 along with the peaks of other functional groups. HRSEM and HRTEM images confirmed cubic structure validating the XRD results. The band gap of the synthesized nanoparticles decreased from 3.25 eV to 2.90 eV in comparison with the pristine CeO2 with LuCeO2. XPS results revealed the oxidation state of lutetium as +3. The photocatalytic conditions were optimized and the optimization study confirms that the catalyst effectively degrades the drug. The degradation efficiency was calculated and was observed to be 92%. Real sample analysis was also performed using Brufen 200 tablet which confirms the practical application of the photocatalyst.

Synthesis and photocatalytic evaluation of 2D MoS2/TiO2 heterostructure photocatalyst for organic pollutants degradation

This study presents a successful method for synthesizing a 2D MoS2/TiO2 nanocomposite through hydrothermal synthesis. The amount of MoS2 in the composite was 5–10 wt% to optimize the heterojunction formation to enhance the photocatalytic degradation of the organic rhodamine under visible light. The prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDX), UV-diffuse reflectance spectroscopy (UV-DRS), and Fourier transforms infrared spectroscopy (FTIR) techniques. High-resolution TEM imaging confirmed the successful exfoliation of few-layer MoS2 nanosheets with lateral sizes ranging from 200 to 800 nm. Based on the results obtained, it was determined that the most effective loading of MoS2 was 5.0 wt% for achieving efficient rhodamine photodegradation under UV–visible light, outperforming both the ten wt. % MoS2 loading and pristine TiO2. The present study highlights the superior photocatalytic performance of the 5.0 wt% MoS2-TiO2 nanocomposite can be attributed to proper heterojunction formation and enhanced charge transfer leading to delayed recombination.

Photocatalytic degradation of bisphenol A by temperature-sensitive magnetic hydrogel with enhanced service life

Easy diffusion and low reusability limit the practicality of photocatalysts. In this study, a hollow sphere (HS) heterojunction was synthesized based on oxygen-doped carbon nitride (OCN) and layered double hydroxides (LDHs). A thermosensitive HS hydrogel (HS Gel) was prepared by mixing HS with N-isopropylacrylamide. Bisphenol A (BPA), being widely manufactured and used in commercial and domestical products and its high toxicity, was chosen as the target pollutant to demonstrate the photocatalytic ability and practicality of the HS Gel. HS Gel presented effective BPA degradation (95% degradation in 70 mins, 4.2 × 10−2 min−1 of kobs) at ambient temperature which is much better than kobs = 1.8 × 10−2 min−1 of OCN and kobs = 0.08 × 10−2 min−1 of LDH), and increased by two-fold the recycling service life (retention of >80% degradation efficiency after 13 usage cycles) compared to other carbon-based photocatalysts (retention of >80% degradation efficiency after 5–6 usage cycles). This is due to its multifunctional characteristics (magnetic property and thermal sensitivity). Under ambient temperature, the hydrophilic HS Gel swelled in the aqueous solution, which promoted the photocatalytic reaction between HS and BPA in the gel state. After the reaction, the HS Gel was subjected to shrinkage by high temperature heating to enhance the mechanical strength for recovery. The magnetic recovery was realized by the paramagnetic properties of layered double oxide to reduce environmental interference. Detailed studies of HS gel related to enhanced service life were conducted including structural changes, catalyst leaking and magnetic changing. A new kind of type Ӏ plus Z-scheme mechanism was also proposed based on the Kubelka-Munk equation, UV diffuse reflectance spectroscopy and Mott-Schotty technique.

Comparative study between Ni–Co ferrite and multi rare earth element doped Ni–Co ferrite

This paper reports the synthesis and analysis of structural, spectral, dielectric and magnetic properties of nano sized multi rare earth (RE) element doped Ni0.5Co0.5Gd0.002Tb0.002Dy0.002Ho0.002Er0.002Fe1.99O4 (NCFR5). The structural and functional properties of this compound was compared with the parent Ni0.5Co0.5Fe2O4 (NCF). Ni0.5Co0.5Fe2O4 and Ni0.5Co0.5Gd0.002Tb0.002Dy0.002Ho0.002Er0.002Fe1.99O4 with five different heavy rare earth elements at octahedral B-site were successfully synthesized by sol–gel method. X-ray diffraction measurements supported the spinel ferrites' single-phase formation. With doping, the lattice parameter was increased from 8.218 Ao to 8.243 Ao. Evaluation of Rietveld refinement of NCF and NCFR5 samples was done. Scanning electron microscopy surface morphology studies revealed the existence of nanoscale grains for both compositions. The existence of five RE elements in NCFR5 was proved by ICP MS analysis. Room temperature UV Diffuse Reflectance Spectroscopy was performed on NCF and NCFR5, and it was discovered that NCFR5 had a greater direct bandgap than NCF. To comprehend the distribution of ions in A and B sites, Raman and Mossbauer spectroscopy were used. It was discovered that rare earth doping significantly affected the magnetic and dielectric characteristics. Multi RE element doping increased strain sensitivity in NCFR5.

Photocatalytic and bactericidal behaviors of Ag/TiO2 doped biochar through Ball–milling approach

Biochar materials derived from various biomass feedstocks have attracted considerable interest as high-performance sorbents for a wide range of contaminants in wastewater. However, the diligence and preoccupation in developing multifunctional materials with interesting properties has prompted researchers worldwide to consider the functionalization of pure biochar for more beneficial applications. In this study, for the first time, a novel ternary photocatalyst was successfully prepared from date palm rachis biochar (BDPR) and silver-doped titanium dioxide (Ag/TiO2) nanoparticles with different Ag/Ti weight ratios using a simple and environmentally friendly ball milling technique. The structural and physicochemical properties of the resulting photocatalysts were investigated by various characterization methods, namely X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA) and UV-diffuse reflectance spectroscopy (UV-DRS). The photocatalytic property of the photocatalysts was evaluated through the degradation of organic dyes, namely, methylene blue (MB) and Congo red (CR). The results show that the photocatalytic activity was greatly enhanced with increasing silver content compared to the neat and TiO2-doped biochars. Complete removal of methylene blue was achieved after 90 and 75 min for 5 %Ag/TiO2-BDPR and 10 %Ag/TiO2-BDPR, respectively, while it took 150 min for 100% photodegradation of Congo red. This was due to the synergistic effect of biochar, silver and TiO2 in trapping electrons and reducing the recombination of e-/h+ pairs. In addition, the photocatalysts could be regenerated and reused for up to 5 cycles without significant degradation of their properties. Furthermore, both 5% and 10% Ag/TiO2 BDPR photocatalysts exhibited high antibacterial activity against E. coli and S. aureus bacteria due to the combined effect of biochar as a sorbent, reactive oxygen species (ROS) and silver.

Bifunctional WO3-AgInS2 nanocomposite material: Enhanced electrical property and photocatalytic activity for degradation of methylene blue dye under visible-light irradiation

Nanocomposite material based on WO3-AgInS2 with different weight percentages of AgInS2 is synthesized using solid-state reaction method. Several analytical methods confirm that the heterostructure WO3-AgInS2 nanocomposite can be used as an electric material as well as a photocatalyst for the degradation of methylene blue (MB) dye under visible light. X-Ray diffraction, Scanning Electron Microscopy-Energy Dispersive X-ray, Transmission Electron Microscopy, and UV-Diffuse Reflectance spectroscopy were used to characterize the synthesized nanocomposites. AC Impedance measurements show that the addition of the semiconductor AgInS2 suppresses electronic conductivity and increases the ionic conductivity compared to pure WO3. Nanocomposite containing 20 wt. % AgInS2 (20-WAIS) was found to have higher ionic mobility, with ionic conductivity of 1.00×10−2 Scm−1 at ambient temperature and bulk resistance of 7.50 Ω. The most effective photocatalytic activity for MB decolorization was shown by 20-WAIS nanocomposite and 97 % degradation of MB was achieved within 50 min of visible-light illumination. The enhanced photocatalytic activity might be the result of a direct Z-Scheme mechanism that maintains charge separation ability throughout time. 20-WAIS nanocomposite exhibits structural and morphological changes that are very significant to the increase of conductivity and outstanding photocatalytic activity. Energy and environmental concerns may be addressed and alleviated as a result of the research undertaken in the present study.

Fabrication of BrO3- bridged Cr2Bi3O11 for enhanced photocatalytic degradation of phenol under visible light

Water pollution caused by organic pollutants seriously affects the ecosystem and human health, and photocatalytic oxidation is considered as a promising method for organic pollutant degradation. In this work, different amount of BrO3- is introduced into Cr2Bi3O11 (Br-Cr2Bi3O11), which was confirmed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). UV diffuse reflectance spectroscopy (DRS) demonstrates that Br-Cr2Bi3O11 has a narrower band gap. In-situ X-ray photoelectron spectroscopy demonstrates that BrO3- can act as an electron bridge to capture electrons under light, and the captured electrons reacted with dissolved oxygen to form ·O2−, which improved the oxidation activity of the catalyst. In addition, the separation of photogenerated carriers of the catalyst is investigated using photoelectron tests. Based on radical capture experiments and electron spin resonance (ESR), it is demonstrated that the main active species was ·O2−. The experimental results show that BrO3- electron bridge can promote the separation of photogenerated carriers and improve the activity of the catalyst. According to all the experimental and characterization results, a mechanism for the separation and transfer of photogenerated charges is proposed.

Mechanism of Extracting Germanium from Ge-Containing Solution with Tannins

The process of germanium–tannin complex is the oldest form of technology for extracting germanium from Ge-containing solutions. This reaction mechanism is relatively controversial as it imposes restrictions on ideas and methods for reducing the amount of tannin. In this paper, using SEM, TEM, FT-IR, XPS, NMR, TOF-SIMS and UV diffuse reflectance spectroscopy for a deep analysis of germanium–tannin complex, the mechanism of extracting germanium from Ge-containing solutions with tannins is investigated. The results show that the theoretical tannin complex mass is 30 times that of tannin mass, and the complex rate reaches 98.84%. The changes of -OH stretching band in FT-IR spectra, the emergence of C3H3GeO7, C2H3GeO6, and C8H7GeO7 in TOF-SIMS images, and the shift of Ge and O banding energy in XPS detail spectra provided definitive evidence for the germanium–tannin complex process, highlighting that the formed complexes of tannins with germanium involve six coordinate Ge-O bonds, which are obtained through orthophenol hydroxyl groups in tannins reacting with Ge4+. Furthermore, the complex mode of germanium–tannins is layer polymerization, which finally forms an agglomeration of complex flocs. The findings of this research is innovative, and can have a profound impact on the future introduction of various methods to reduce the mass of tannins.

Construction and performance of a novel CuBi2O4/In2O3 Z-scheme heterojunction photocatalyst

A novel all-solid-state Z-scheme visible-light-driven photocatalytic material, CuBi2O4/In2O3 was successfully prepared by loading CuBi2O4 onto flower-like In2O3. The resulting material was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, UV-diffuse reflectance spectroscopy (UV-DRS), Brunauer–Emmett–Teller (BET) surface area, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), Raman spectroscopy, and X-ray diffraction (XRD). Compared with single-phase CuBi2O4 and In2O3, the coupled composite phase of 15% CuBi2O4/In2O3 (15CuIn) showed superior photocatalytic activity. Its decolorization rate of methylene blue (MB) could reach 97% in 80 min under visible light irradiation and could be maintained at 85% after four cycles. The outstanding photocatalytic performance of CuBi2O4/In2O3 was attributed to the formation of a Z-scheme heterogeneous structure, which increased the visible light absorption, enhanced the specific surface area, and improved the interfacial charge transfer efficiency. This study provides a novel approach for the construction of efficient heterojunction photocatalysts for wastewater treatment.

Biosynthetic modulation of carbon-doped ZnO for rapid photocatalytic endocrine disruptive remediation and hydrogen evolution

Pharmaceuticals and industry effluents such as dyes, and organic contaminants in wastewater are being identified among the top endocrine disruptive compounds with inherent recalcitrant and hazardous effects. Herein, microwave-induced coconut shell-activated carbon-doped-zinc-oxide (CSAC-ZnO) nanocomposites at various calcined temperatures were synthesized by hydrothermal techniques, characterized and applied towards photocatalytic degradation of endocrine disruptive compounds (EDC) and green energy generation via photocatalytic hydrogen production. The surface area, structural crystallinity, optical properties, thermal stability, functional group and morphological properties were accessed via Powdered X-ray diffraction, UV-Diffuse Reflectance Spectroscopy, Fourier Transform Infrared, Thermal Gravimetric Analysis, Brunauer-Emmett-Teller, X-ray Photoelectron Spectroscopy, Scanning Electron Microscopy, and Transmission Electron Microscopy. An extremely high surface area of 320.65 m2g-1 was observed from the as-prepared carbon decorated (CSAC-ZnO) and excellent light absorption was shown by all the photocatalysts. The exceptional photo-degradation efficiencies of CSAC-ZnO on methylene blue (MB) cationic dye as well as ibuprofen (IBP) pharmaceutical are reported. Very rapid 91% MB and 94% IBP pharmaceutical degradation efficiency obtained within 60 min and 30 min, respectively were observed. The kinetics of the photocatalytic activities at different pH followed pseudo-first-order kinetics. The Liquid Chromatography-Mass Spectrometry analysis on MB and IBP before and after photodegradation confirmed the formation of intermediate products. The modulated CSAC-ZnO@600 exhibits hydrogen production of 18947μmolg−1h−1. The photocatalysts showed current densities ranging from 0.03 to 0.05 mA/cm2. The Fast charge transfer is supported by electrochemical impedance spectroscopy and −0.3 and −0.49 V versus Ag/AgCl flat band potentials. The relation between the electronic and catalytic properties is revealed from the calculation of density functional theory (DFT). The study revealed the impact of calcination on the properties of the biomass carbon-doped-photocatalysts, excellent photocatalytic degradation efficiency and efficient hydrogen production from water-splitting giving relevance to biomass carbon-doped CSAC-ZnO in environmental remediation and green energy production.

Preparation of Z‐type heterojunction SiCf/g‐C3N4 composites with enhanced photocatalytic degradation of tetracycline under visible light

Novel visible light‐driven silicon carbide‐based composites were prepared via in situ deposition of g‐C3N4 on fibrous SiC. The X‐ray diffractometry, scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectrometer characterization showed that a Z‐type heterojunction was formed. According to the UV diffuse reflectance spectroscopy and (αhv)1/2 versus hv plots, it was demonstrated that the addition of g‐C3N4 extended the light absorption of the sample in visible light, narrowing its band gap. The EIS plots and PL spectra showed an increase in the efficiency of the charge carriers' mobility of the sample and a decrease in the recombination of its photogenerated electron–hole pairs. The photocatalytic degradation experiments showed that using a 0.03‐g·L−1 suspension concentration and a pollutant concentration of 10 mg·L−1, the degradation rate under visible light irradiation was 100 and 3.6 times higher than that of bare SiCf and g‐C3N4, respectively. The possible photocatalytic mechanism was proposed based on reactive species capture experiments and electron paramagnetic resonance showing that ·O2− and e− were the active entities.