BiVO4 powder was synthesized by a simple hydrothermal method. The nanobelts with well dispersed and uniform morphology were synthesized by controlling the temperature. The structure of BiVO4 powder was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The diameter of the nanobelts was about 50 nm. The structure and composition of the nanobelts were studied by X-ray diffraction (XRD), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). The absorption intensity of BiVO4 powder in UV-Vis region was compared by UV–vis diffuse reflectance spectroscopy. As a photocatalyst, BiVO4 nanobelts have good photocatalytic ability under visible light irradiation, which is very useful for the treatment of environmental wastewater. The synthesized nanobelts photocatalyst can be reused without destroying its structure. The reusability and chemical stability of photocatalysts are of great significance for practical application.

Practical applications of CsPbX3 nanocrystals (NCs) are limited by their poor stability. The formation of heterojunction between CsPbX3 NCs and oxides is an effective means to protect perovskite from polar solvents and other external factors. Significantly improving the stability and photocatalytic properties of the core/shell perovskite is very important for its application in photoelectric and photocatalytic technology. Here, we report the synthesis of asymmetrical CsPbBr3/TiO2 core-shell heterostructure NCs at single particle level by hot injection liquid phase synthesis and sol-gel method, where each CsPbBr3 NCs is partially covered by titanium dioxide. It is shown that the type II arrangement is generated at the heterogeneous interface, which greatly facilitates the separation of electron-hole pairs and increases the carrier transport efficiency. More crucial, due to the protection of titanium dioxide shell, the product has higher long-term stability in humid air compared with bare CsPbBr3 NCs. The asymmetrical core-shell heterostructure prepared in this study not only improves the stability of CsPbX3 NCs, but also provides some ideas for optoelectronic device applications and TiO2-based photocatalysts.

The development of oxidation processes with generating powerful radicals is the most interesting and thought-provoking dimension of peroxymonosulfate (PMS) activation. In this study, a magnetic spinel CuFe2O4 was successfully prepared by a facile, non-toxic, cost-efficient co-precipitation method with the synergetic effect of photocatalytic PMS oxidation against recalcitrant benzotriazole (BTA) pollutant. The high particle dispersion and large surface area (201.898 m2/g) provided a high photocatalytic activity with CuFe2O4. The obtained results from the central composite design (CCD) analysis confirmed the optimum degrading rate of BTA reached 81.4% at the optimum operational condition of CuFe2O4= 0.4 g/L, PMS= 2 mM, BTA= 20 mg/L after 70 min irradiation time. As such, the active species capture experiments revealed the presence of •OH, SO4•‒, O2•‒ and h+ species in CuFe2O4/UV/PMS system where SO4•‒ was dominated for BTA photodegradation. The combination of photocatalysis and PMS activation enhanced the consumption of metal ions in redox cycle reactions, thus preventing metal leaching and maintain the recyclability with reasonable mineralization efficiency which achieved more than 40% total organic carbon removal after four batch experiments. A retardant effect on BTA oxidation was observed with comparing the water’s common anion constituents as HCO3‒ > Cl‒ > NO3‒ > SO2‒. Results from intermediates identification showed that the transformation pathway of BTA developed as the deprotonation, hydrolysis and ring cleavage processes promoting the practical potential of photo-absorbing CuFe2O4 catalyzed PMS which can be a promising method due to convenient magnetic separation form the solution.

The present study focuses on the synthesis, characterization, and investigation of a p-n heterojunction photocatalysis. Titanium dioxide (TiO2) can’t alone induce the photocatalytic water splitting due to its wide bandgap, which decreases its catalytic activity in the visible light. To make redshift of absorptivity for the TiO2, Nickel (Ni)-doped Graphene (rGO) supported TiO2 was synthesized. Several characterization techniques have been employed to validate the composition and the light absorption ability of the prepared photocatalysts including TEM, SEM, EDS, XRD, XPS, and UV-Vis spectroscopy. The characterization revealed successful doping of the Ni and TiO2 on the rGO nanosheet. Moreover, the UV-Vis spectroscopy indicated a significant shift of light absorption toward the visible spectrum. The photon-induced evolution of H2 was remarkably enhanced using the prepared Ni-rGO/TiO2 nanocomposite. Furthermore, the optimum ratio of rGO: TiO2: Ni in the hybrids was 10:1:4, while the higher Ni ratio would decrease the photocatalytic activity. The stability of the photocatalyst was also verified during 8 cycles of photocatalytic reactions. The kinetic study revealed the nature of the integrated reaction and the controlling step governing the reaction sequence. .

Nucleophilic aromatic substitution (SNAr) reactions can provide metal-free access to synthesize mono-substituted aromatic compounds. We have developed efficient SNAr conditions for p-selective substitution of polyfluoroarenes with phenothiazine in the presence of a mild base to afford the corresponding 10-phenylphenothiazine (PTH) derivatives. The resulting polyfluoroarene-bearing PTH derivatives were subjected to a second SNAr reaction to generate highly functionalized PTH derivatives with potential applicability as photocatalysts for the reduction of carbon–halogen bonds.

Heavy metals are non-biodegradable and have a high toxicity effect to living things which makes their presence in the environment extremely dangerous. The method of handling heavy metals waste by photocatalysis techniques using TiO2/SiO2 composite showed a good performance in reducing harmful pollutants. In this study, SiO2 from Bengkulu beach sand was used as a support material for TiO2 photocatalyst to reduce Cr(VI) and Pb(II) concentrations. SiO2 was obtained through leaching techniques using NaOH as a solvent. The TiO2/SiO2 composite photocatalyst were synthesized using a solvothermal method at 130 °C and then characterized using XRD, FTIR, SEM and PSA. Based on the XRD diffractogram, the synthesized TiO2 showed the anatase structure while the SiO2 showed the amorphous structure. Ti-O-Si bond is defined in the IR spectra, which indicates that the relationship between TiO2 and SiO2 is a chemical interaction. The results of SEM and PSA characterizations show agglomerated spherical (round) particles with a mean particle size of 616.9 nm. The TiO2/SiO2 composite of 7:1 ratio showed the highest photocatalytic activity after 180 minutes of UV irradiation, with a concentration-decrease percentage of 93.77% and 93.55% for for Cr(VI) and Pb(II), respectively.

The TiO₂ nanostructures resulted by pyrolysis of TiCl₄ at low temperature of 80 ^oC are found to be a mixture of amorphous TiO₂ complexes and anatase nanostructure whose ratio depends on the pH of the pyrolysis medium. At low pH level, the resulting TiO₂ nanostructure is predominant anatase and gradually shifts to the amorphous TiO₂ complexes with pH level increasing. By means of heat treatment, the amorphous TiO₂ complexes can be converted back to the anatase nanostructure and then transform to rutile with the elevating temperature. Amongst of the TiO₂ nanostructure recovered from amorphous TiO₂ complexes, the anatase shows to be the most effective photocatalyst in decomposition of methylene blue.

Semiconductor materials have been shown to have better photocatalytic behavior and can be utilized for the photodegradation of organic pollutants. In this work, three-dimensional flower-like SnS₂ were synthesized by a facile hydrothermal method. Core-shell structured SiO₂@α-Fe₂O₃ nanocomposites were then deposited on the top of the SnS₂ flowers. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET) and photoluminescence spectroscopy (PL). The photocatalytic behavior of the SnS₂-SiO₂@α-Fe₂O₃ nanocomposites was observed by observing the degradation of methylene blue (MB). The results show an effective enhancement of photocatalytic activity for the degradation of MB especially for the 15 wt. % SiO₂@α-Fe₂O₃ nanocomposites on SnS₂ flowers.

The photocatalytic biohydrogen generation using ZnO with the aid of simultaneous deposition of copper from an aqueous biomass-derivative glycerol solution was investigated. The effects of concentration of glycerol solution, Cu ion concentration and reaction temperature on biohydrogen generation were investigated. The photocatalytic biohydrogen production rate increased with increasing the concentration of aqueous glycerol solution, and the observed data could be fitted to the Langmuire-Hinshelwood kinetic models. The photocatalytic H2 production efficiency with ZnO could be significantly improved by simultaneous Cu deposition. The photocatalytic biohydrogen production rate was dependent on temperature, and increased with the increasing temperature. The possible mechanisms for oxidation of glycerol solution and photocatalytic hydrogen generation were proposed.

In this study, functionalized-MWCNTs with 3-aminopropyltriethoxysilane (APTES) loaded titania nanoparticles (MWCNTs-APTES-TiO₂) were prepared to investigate their physicochemical properties and photocatalytic activity for methyl orange (MO) degradation. The TiO₂ nanoparticles, functionalized-MNCNT and composite powders were characterized by XRD, raman, and TEM. The results obtained proved that titania (TiO₂) nanoparticles was successfully loaded on APTES-MWCNTs. The best photocatalytic degradation of methyl orange solution under UV light irradiation was recorded over MWCNTs-APTES-TiO₂ (1:2), with 87% after 180 min. Kinetic analysis indicated that photocatalytic degradation of MO solution by MWCNTs-APTES-TiO₂ obeyed second-order kinetic model (R² > 0.95), supported by half-life equations and graph. The presence of carbon nanotubes accelerated the degradation of methyl orange due to inhibition of electron-hole recombination, the formation of additional hydroxyl radicals and functional groups of the latter had an inhibitory effect on the degradation of methyl orange. This study shows that the MWCNTs-APTES-TiO₂ nanocomposites exhibit promising photocatalytic degradation against methyl orange.

Zinc nanoparticles (ZnNPs) open new opportunities for biomedical applications as a strategy against microbes and dye removal in an efficient way. The composite ZnNPs using Rhododendron arboreum (R. arboreum) stem bark were synthesized and characterized for UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The synthesized nanoparticles showed zones of inhibition of 23±0.09, 18±0.1 and 16±0.05 mm, against the Klebsiella pneumoniae (K. pneumoniae), Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against K. pneumoniae, S. aureus, and E. coli were found to be 34±0.21 and 72.71±0.47, 47±0.11 and 94.86±0.84 and 94±0.18 and 185.43±0.16 µg/mL, respectively. The biosynthesized ZnNPs resulted in significant eradication of the outer and inner membranes of the bacterial cells. Likewise, the synthesized ZnNPs showed time-dependent photocatalytic degradation activity and revealed 65% methyl orange dye degradation with an irradiation period of 6 hours. The findings of this study suggest the suitability of the novel R. arboreum stem bark-based ZnNPs as an effective ameliorant against bactericidal activities and photocatalysts for the removal of hazardous water contaminants.

Nanocomposites of TiO₂ Degussa P25 nanoparticles/activated carbon (TiO₂/AC ) were prepared at various mass ratios of (4:1), (3:2), (2:3), and (1:4) by a facile process. The effects of TiO₂/AC mass ratios on the structural, morphological, and photocatalytic properties were systematically studied in comparison with bare TiO₂ and bare AC. TiO₂ nanoparticles exhibited dominant anatase and minor rutile phases, and a crystallite size of approximately 21 nm; while AC had XRD peaks of graphite and carbon, and a crystallite size of 49 nm. The composites exhibited tight decoration of TiO₂ nanoparticles on micron-/submicron AC particles, and uniform TiO₂/AC composites were obtained as evidenced by the uniform distribution of Ti, O, and C in an EDS mapping. Moreover, Raman spectra show the typical vibration modes of anatase TiO₂ (e.g., E_1g⁽¹⁾, B_1g⁽¹⁾, E_g⁽³⁾) and carbon materials with D and G bands. The TiO₂/AC with (4:1), (3:2), and (2:3) possessed higher reaction rate constants (k) in photocatalytic degradation of methylene blue (MB) than that of either TiO₂ or AC. Among the investigated materials, TiO₂/AC = 4:1 achieved the highest photocatalytic activity with a high k of 55.2×10^-3 min^-1 and an MB removal efficiency of 96.6% after 30 min treatment under UV-Vis irradiation (120 mW/cm²). The enhanced photocatalytic activity for TiO₂/AC is due to the synergistic effect of the high adsorption capability of AC and the high photocatalytic activity of TiO₂. Furthermore, TiO₂/AC promotes the separation of photoexcited electron/hole (e^-/h⁺) pairs to reduce their recombination rate and thus enhance photocatalytic activity. The optimal TiO₂/AC composite in this study can be used for treating industrial or household wastewater with organic pollutants.

Phosphorus, an essential rare element in aquatic ecosystems, plays a key role in maintaining ecosystem balance. However, an excess of phosphorus will lead to eutrophication and algal pro-liferation. To prevent eutrophication, it is crucial to pretreat and measure the concentration of total phosphorus (TP). Compared with conventional TP pretreatment equipment (autoclave), a lab-on-a-chip detection device fabricated through micro-electromechanical system technology using titania (TiO2) as a photocatalyst is more convenient, efficient, and cost-effective. However, the wide bandgap of TiO2 (3.2 eV) limits the photocatalytic activity. To address this problem, this paper describes the preparation of a TiO2/Au nanocomposite film by electron-beam evaporation and atomic layer deposition, based on the introduction of a gold film and TiO2 on a quartz substrate. The photocatalytic degradation properties of TiO2/Au nanocomposite films with thicknesses of 1, 2, 3, and 4 nm are assessed using rhodamine B as a pollutant. Experimental results demonstrate that the deposition of a gold film with different thicknesses can enhance the photocatalytic degradation efficiency through synergetic reactions in the charge separation process on the surface. The optimal photocatalytic efficiency is achieved when the deposition thickness is 2 nm, and it decreases with further increase in the thickness. When the photocatalytic reaction time is 15 min, the LOC device with a 2-nm-thick gold layer and autoclave exhibit similar TP pretreatment performance. Therefore, the proposed LOC device based on photocatalysis technology can address the limitation of conventional autoclave equipment, such as large volume, long processing time, and high cost, thereby satisfying the growing demand for on-site evaluation.

Three-Dimensional mesoporous TiO2 scaffolds of anatase phase possess inherent eximious optical behavior that are beneficial in designing photoelectrodes for solar energy conversion applications. However, substantial efforts have been devoted in maximizing the UV and/or visible light absorption efficiency, and suppressing the annihilation of photogenerated charged species in pristine mesoporous TiO2 structure for improved solar illumination conversion efficiencies. This study provides the fundamental insights into Mxene functionalized mesoporous TiO2 as photoelectrode for the first time. This novel combination of Mxene functionalized TiO2 electrodes with and without TiCl4 treatments have been successfully optimized to intensify the process of photon absorption, charge segregation and photocurrent, resulting in superior photoelectrode performance. The photocurrent measurements of prepared photoelectrodes are significantly enhanced upon increased contents of Mxene due to improved absorption efficiency within the visible region as verified by UV–Vis absorption spectroscopy. Moreover, as evident through structural analysis, the anatase phase of TiO2 is well grown due to increased contents of Mxene and post-deposition heat treatments. Consequently, an appreciable coverage of well-developed grains on FTO surface observed in SEM images. Thereby, the newly fabricated conductive mesoporous TiO2 photoelectrodes are potential candidates for photoinduced energy conversion and storage purposes.

Since the photocatalytic reaction is a surface reaction, enhancing the gas movement around photocatalyst would promote photocatalytic CO₂ reduction performance. A new approach to enhance the gas movement around the photocatalyst by the natural thermosiphon movement of gasses around photocatalyst using black body material was proposed and confirmed experimentally, but the heat transfer mechanism on the phenomena was not clarified yet. The purpose of this study is to clarify the heat transfer mechanism of it. This study calculated the temperature of mixed gases of CO₂ and NH₃ around P₄O₁₀/TiO₂ photocatalyst by the heat transfer formula. It is revealed that there was no difference between the increase temperature (T_g) from the temperature at the beginning of the CO₂ reduction experiment (T_ini) and the temperature of mixed gases of CO₂ and NH₃ measured by thermocouple in the experiment (T_e) under the illumination condition with a visible light (VIS) + an infrared light (IR) and IR only. The heat transfer model proposed by this study has predicted T_g well under the illumination condition with VIS + IR and IR only well. On the other hand, it is revealed that the difference between T_g and T_e was as large as 10 ℃ under the illumination condition with an ultra violet light (UV) + VIS + IR.

Fluorinated compounds and co-enzymes are being widely researched and employed throughout research community because of their versatile physical, chemical and biological properties. In this work, we synthesized NiS-NiO/S-g-C3N4, a highly effective photocatalyst for C(sp3)-F bond activation and the regeneration of coenzyme (1,4-NADH) employing a new and ecologically acceptable route. The obtained photocatalyst exhibited important photocatalytic properties, such as good solar light harvesting ability, suitability of the optical band-gap, and facilitating efficient charge migrations. As a result, the newly designed NiS-NiO/S-g-C3N4 photocatalyst shows the excellent yield for regenerations of 1,4-NADH (51%). Further, a method of combining C(sp3)-F bond activation with photocatalysis has been demonstrated that represents a very powerful and sustainable approach, that can be a major breakthrough for the field of pharmaceutical.

The present study investigates the relationship between the local structure, photocatalytic ability, and cathode performances in sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs) using Ni-substituted goethite nanoparticles (Ni_xFe_1-xOOH NPs) with a range of 'x' values from 0 to 0.5. The structural characterization was performed applying various techniques, including X-ray diffractometry (XRD), Thermogravimetry differential thermal analysis (TG-DTA), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray absorption spectroscopy (XANES/EXAFS), both measured at room temperature (RT), and ⁵⁷Fe Mössbauer spectroscopy recorded at RT and at low temperatures (LT) from 20 K to 300 K, Brunauer-Emmett-Teller surface area measurement (BET), and diffuse reflectance spectroscopy (DRS). In addition, the electrical properties of Ni_xFe_1-xOOH NPs were evaluated by impedance spectroscopy. XRD showed the presence of goethite as the only crystalline phase in prepared samples with x ≤ 0.20, and goethite and α-Ni(OH)₂ in the samples with x > 0.20. Sample with x = 0.10 (Ni10) showed the highest photo-Fenton ability with a first-order rate constant value (k) of 15.8×10^-3 min^-1. The ⁵⁷Fe Mössbauer spectrum of Ni0, measured at RT, displayed a sextet corresponding to goethite, with an isomer shift (δ) of 0.36 mm s^-1 and a hyperfine magnetic distribution (B_hf) of 32.95 T. Moreover, the DC conductivity decreased from 5.52×10^-10 to 5.30×10^-12 (Ω.cm)^–1 with 'x' increasing from 0.10 to 0.50. Ni20 showed the highest initial discharge capacity of 223 mAh g^-1, attributed to its largest specific surface area of 174.0 m² g^-1. In conclusion, Ni_xFe_1-xOOH NPs can be effectively utilized as visible-light-activated catalysts and active cathode materials in secondary batteries.