Collaborative adsorption and photocatalytic degradation of high concentration pharmaceutical pollutants in water using a novel dendritic fibrous nano-silica modified with chitosan and UiO-66.

This study presents a novel hybrid mesoporous material for degrading drug pollutants in water. The hybrid materials, derived from UiO-66 metal-organic framework and chitosan, coated on nano-silica, showed excellent drug adsorption through hydrogen-bonding interactions and efficient photodegradation of antibiotics. The hybrid material's enhanced conductivity and reduced band gap significantly improved pollution reduction by minimising electron-hole recombination. This allows for more efficient charge transport and better light absorption, boosting the material's ability to break down pollutants. Structural and morphological analyses were conducted using various techniques, including scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Optimising the adsorption-photodegradation process involved investigating pH, catalyst dose, and radiation time. Non-linear optimisation revealed an efficiency exceeding 85 % for 400 mg/L tetracycline and doxycycline, the model antibiotics. The optimal parameters for maximal elimination were determined as pH = 4.3, hybrid mesosphere dose = 4.0 mg/mL, and radiation time = 10 min. Kinetic studies favored pseudo-second-order diffusion models over pseudo-first-order models. The hybrid mesosphere showed sustained efficiency after three cycles and performed well in real aqueous samples, removing over 80 % of each antibiotic. This study demonstrates the potential of the hybrid mesoporous material for removing pharmaceutical pollutants in water systems.

The effect of the number of SO3- groups on the adsorption of anionic dyes by the synthesized hydroxyapatite/Mg-Al LDH nanocomposite.

In this study, a new nanocomposite of hydroxyapatite (HA)/Mg-Al layered double hydroxide (LDH) was successfully formed via a facile co-precipitation method and applied to adsorb three anionic dyes of alizarin red S (ARS), Congo red (CR), and reactive red 120 (RR120) differing in the number of SO3- groups from aqueous solution. Based on a combination of characterization analysis and adsorption experiments, HA/Mg-Al LDH nanocomposite showed better adsorption performance than HA and Mg-Al LDH. Using XRD and TEM analyses, the crystallinity and the presence of nanoparticles were confirmed. According to the SEM investigation, the Mg-Al LDH layers in the nanocomposite structure were delaminated, while HA nanorods were formed at the surface of Mg-Al LDH nanoparticles. The higher BET surface area of the novel HA/Mg-Al LDH nanocomposite compared to HA and Mg-Al LDH provided its superior adsorption performance. Considering an effective amount of adsorbent dosage, pH 5 was selected as the optimum pH for each of the three dye solutions. According to the results from the study of contact time and initial concentration, the pseudo-second-order kinetic (R2 = 0.9987, 0.9951, and 0.9922) and Langmuir isotherm (R2 = 0.9873, 0.9956, and 0.9727) best fitted the data for ARS, CR, and RR120, respectively. Anionic dyes with different numbers of SO3- groups demonstrated distinct adsorption mechanisms for HA and Mg-Al LDH nanoparticles, indicating that the adsorption capacity is influenced by the number of SO3- groups, with HA/Mg-Al LDH nanocomposite offering superior performance toward dyes with higher numbers of SO3- groups. Furthermore, ΔH° less than 40 kJ/mol, positive ΔS°, and negative ΔG° accompanied by the mechanism clarifying show physical spontaneous adsorption without an external source of energy and increase the randomness of the process during the adsorption, respectively. Finally, the regeneration study demonstrated that the nanocomposite could be utilized for multiple adsorption-desorption cycles, proposing the HA/Mg-Al LDH as an economically and environmentally friendly adsorbent in the adsorption of anionic dyes in water treatment processes.

Design and synthesis of high performance magnetically separable exfoliated g-C3N4/γ-Fe2O3/ZnO yolk-shell nanoparticles: a novel and eco-friendly photocatalyst toward removal of organic pollutants from water.

Herein, a new visible-light active exfoliated g-C3N4/γ-Fe2O3/ZnO yolk-shell nanoparticles (NPs) was synthesized as a magnetically separable photocatalyst. For an in-depth understanding of the magnetic photocatalyst's structural, morphological, and optical properties, the products were extensively characterized with FT-IR, XRD, TEM, HRTEM, FESEM, EDS, EDS-mapping, VSM, DRS, EIS, and photocurrent. The photocatalyst was then utilized to degrade Levofloxacin (LEVO) and Indigo Carmine (IC) by visible light at room temperature. The exfoliated g-C3N4/γ-Fe2O3/ZnO yolk-shell NPs photocatalyst revealed 80% and 95.6% degradation efficiency for Levofloxacin and Indigo Carmine within 25 and 15 min, respectively. In addition, the optimal factors such as concentration, loading of photocatalyst, and pH were also assessed. Levofloxacin degradation mechanistic studies showed that electrons and holes significantly contribute to the photocatalytic process of photocatalyst degradation. In addition, after 5 times regeneration, exfoliated g-C3N4/γ-Fe2O3/ZnO yolk-shell NPs remained as an excellent magnetic photocatalyst for the eco-friendly degradation of Levofloxacin and Indigo Carmine (76% and 90%), respectively. The superior photocatalytic performance of exfoliated g-C3N4/γ-Fe2O3/ZnO yolk-shell nanoparticles (NPs) was mostly ascribed to the synergistic advantages of stronger visible light response, larger specific surface area, and the more effective separation and transfer of photogenerated charge carriers. Based on these results, the highly effective magnetic photocatalyst achieved better results than numerous studied catalysts in the literature. The degradation of Levofloxacin and Indigo Carmine under environmentally friendly conditions can be achieved using exfoliated g-C3N4/γ-Fe2O3/ZnO yolk-shell NPs (V) as an efficient and green photocatalyst. The magnetic photocatalyst was characterized by spectroscopic and microscopic methods, revealing a spherical shape and particle size of 23 nm. Additionally, the magnetic photocatalyst could be separated from the reaction mixture by a magnet without significantly reducing its catalytic activity.

A new simple protocol for the synthesis of nanohybrid catalyst for oxidative desulfurization of dibenzothiophene.

This study offers an investigation of the catalytic activity of TiO2/SiO2 during oxidative desulfurization (ODS) of a model fuel that includes dibenzothiophene (DBT), using hydrogen peroxide (H2O2) as a green oxidant in the absence of UV irradiation. For the first time, though a novel and simple protocol, TiO2/SiO2 nanohybrid was synthesized using ascorbic acid and glycerol as green complexing and polymerizing agents, respectively. The TiO2/SiO2 catalyst was thoroughly characterized by XRD, FT-IR, nitrogen adsorption-desorption measurements, TEM, FESEM, and TGA. Results revealed a high catalytic oxidative activity for the catalyst in the removal of DBT regarding sulfur removal up to 99.4% within 20 min under optimum reaction conditions. The main factors affecting the ODS process, including catalyst dosage, temperature, O/S molar ratio, and different oxidizing agents, were evaluated to identify optimum conditions. The desulfurization efficiency of the recoverable catalysts showed no loss in activity after four times. The present article suggests a new and green method for the synthesis and characterization of an efficient catalyst (TiO2/SiO2) in deep oxidative desulfurization at 25 °C and removal of refractory organosulfur compounds that yield ultra-low sulfur fuels. Also, it proved to have a much higher catalytic oxidation capacity when compared to pure TiO2.

Does the addition of a heteropoly acid change the water percolation threshold of PFSA membranes?

A large system containing heteropoly acids (HPAs) and Nafion® 117 was simulated and studied to verify whether the additive particles affect the formation of the water percolating network or not. Two structures of HPA particles were considered as dopants, i.e. H9AlW6O24 and H3PW12O40. The SAXS simulation revealed that HPA particle addition to the membrane matrix leads to an increased order in the abundance and size of the hydrophilic region beside an expansion of the distance between the ionic domains. The morphological assessment shows that the hydrophilic phase domains in the HPA-doped Nafion® were spaced further apart than in the undoped membrane. These results show that adding HPA particles to the PFSA membrane reduces the so-called dead-pockets and makes the water channels more interconnected. For undoped Nafion®, the so-called percolating hydration level (λp) was 5.63. In other words, according to these results, approximately 8 wt% of water molecules are required to establish a spanning water network. The H9AlW6O24 and H3PW12O40 particles directly influence the morphology of water clusters and reduce by 10.12% and 17.41% the required hydration level to reach the percolation threshold, respectively.

The Study on Titanium Dioxide-Silica Binary Mixture Coated SrAl2O4: Eu2+, Dy3+ Phosphor as a Photoluminescence Pigment in a Waterborne Paint.

After proper stimulation, long afterglow phosphors formulated as pigment in waterborne paints can emit light after the removal of the excitation light source. The encapsulation of SrAl2O4: Eu2+, Dy3+ phosphor by TiO2 and SiO2 individually, and in combination by a precipitation method was studied. The water resistance and photoluminescence behavior of the coated phosphors as a pigment for potential use in waterborne photoluminescence paints were evaluated. It revealed that the TiO2- SiO2 content coating layer was precipitated on the studied phosphor successfully. The higher trend of the TiO2 for coating on the phosphor when compared with the SiO2 was observed from EDS spectra. The SEM micrographs showed a continuous and uniform SiO2-TiO2 layer on the coated phosphor. Based on XRD results, the existence of the TiO2 in the coating layer had beneficial effect on the average crystallite size values. The pH solution versus time showed that the availability of the TiO2 in coated layer improved water resistance of the coated phosphor, although, in comparison with SiO2, it was less effective. The coated phosphor with TiO2 had the minimum afterglow brightness decay and consequently, it was recommended as a suitable pigment for waterborne photoluminescence paints.

The effect of the surface coating of a strontium mono-aluminate europium dysprosium-based (SrAl2O4:Eu2+,Dy3+) phosphor by polyethylene (PE), polystyrene (PS) and their dual system on the photoluminescence properties of the pigment.

SrAl2O4:Eu2+,Dy3+ as a known strontium mono-aluminate europium dysprosium-based phosphor is widely used in paints and coating formulations as a photoluminescence pigment. It has two major drawbacks: improper dispersion in organic-based paints and weak water and moisture resistance. To address the above-mentioned drawbacks, the surface coating of phosphors with polyethylene and polystyrene individually and in combination using a solution technique was performed. The FT-IR spectra showed that the used polymers were coated on the phosphor properly. Also, the EDS spectra showed the presence of elemental carbon for the treated phosphors with different amounts. No regular trend was observed for element ratios when the polyethylene content in the coating layer was reduced from 100 to 0%. Based on the XRD patterns, the crystalline structure of the coated phosphors was not affected by the polymeric coated layer. In the SEM micrographs, the sharp and rough edges of the uncoated phosphor changed to a smooth and soft state for the coated phosphors. The brightness of most of the coated phosphors was independent of time and did not change over a period of 5 minutes after UV irradiation. This property makes the polymeric coated phosphors suitable as photoluminescence pigments in all kinds of paints and coatings.

A one-pot route for the synthesis of Au@Pd/PMo12/rGO as a dual functional electrocatalyst for ethanol electro-oxidation and hydrogen evolution reaction.

An in situ one-pot synthetic route for the synthesis of a Au@Pd/PMo12/reduced graphene oxide (rGO) nanocomposite is presented, where the Keggin-type polyoxometalate phosphomolybdic acid (PMo12) is used as both reducing and stabilizing agent. High-angle annular dark-field scanning transmission electron microscopy (HAADT-STEM), transmission electron microscopy (TEM), and X-ray diffraction analysis were applied to fully characterize the core-shell structure of Au@Pd/PMo12 on the rGO matrix. Electrochemical studies showed how this nanocomposite acts as a dual electrocatalyst for the ethanol electro-oxidation reaction (EOR) and the hydrogen evolution reaction (HER). For the EOR, the Au@Pd/PMo12/rGO electrocatalyst offers a low onset potential of -0.77 V vs. Ag/AgCl and a high peak current density of 41 mA cm-2 in alkaline medium. This feature is discussed via detailed cyclic voltammetry (CV) studies illustrating how the superior performance of the synthetic nanocomposite could be attributed to the synergistic effect of Au, Pd, PMo12 and rGO. Moreover, it has been confirmed that the proposed electrocatalyst exhibits low overpotentials for 10 mA cm-2 current density (η 10) in different pH media. The values of η 10 were -109, 300 and 250 mV vs. RHE in acidic, basic and neutral media, respectively. Also, the ability of the electrocatalyst to provide high HER current density and its remarkable stability have been confirmed.

Effect of Adding Nano Size Silica on Setting Time and Porosity of Mineral Trioxide Aggregate.

Introduction: The aim of this study was to evaluate the effect of addition of nano-silica (SiO2) to mineral trioxide aggregate (MTA) on its setting time and porosity. Methods and Materials: The concentration 8% of nano-silica were prepared and added to the MTA powder. After mixing with water the setting time and porosity were evaluated and compared with pure MTA. Statistical analysis was performed using the t-test. The level of significance was set at 0.001. Results: The mean setting time of MTA+8% nano-silica (9.8±0.78) was significantly lower than MTA (23.3±2.16) ( P<0.001). Also the mean porosity by imbibition method in MTA+8% nano-silica (23.49±0.48) was significantly higher than MTA (15.69±2.10) (P<0.001). There was no significant difference in mean porosity by scanning electron microscope (SEM) method in MTA+8% nano-silica (31.26±10.73) and MTA (32.74±5.26) (P>0.001). Conclusion: This in vitro study showed us an addition of 8% of nano-silica to MTA reduced the setting time. Although evaluation by imbibition test showed increasing of porosity in nano-silica MTA compared with pure MTA.

Elucidating the morphological aspects and proton dynamics in a hybrid perfluorosulfonic acid membrane for medium-temperature fuel cell applications.

A perfluorosulfonic acid (PFSA) membrane, i.e. Nafion® 117, was doped with the heteropoly salts (HPS) Cs3PW12O40, Rb3PW12O40, and (NH4)3PW12O40. Also, composite membranes with CsxH3-xPW12O40 (x = 1, 2, and 3) as dopants were investigated, which were rendered insoluble by substituting protons with larger cations. Morphological assessment and a detailed analysis of the hopping events via SAXS measurement and analysis of the hydrogen bond networks were performed using classical and quantum hopping molecular dynamics simulation. The phase segregation decreased by increasing the extent proton substitution in HPA. HPS containing cations with a larger ionic radius induced smaller phase segregation in the membrane, as confirmed by the RDF plots. SAXS simulation revealed that the hydrophilic phase domains in the HPS-doped Nafion® membrane were spaced further apart than that in the HPA-doped membrane. Although there was a greater number of isolated clusters for the Cs3PW12O40-doped Nafion®, the average number of cluster decreased with an increase in the substitution cation/proton ratio and ionic radius of the cation. The analysis of the H-bond network stability revealed that the proton hops slower when the membrane contains HPS particles and the mean residence time of a proton on water molecules increases with an increase in the extent of proton substitution in H3PW12O40. Indeed, for the HPA-doped membrane, the diffusion of water molecules is lower than that in the HPS-doped system.

Solar energy harvesting by magnetic-semiconductor nanoheterostructure in water treatment technology.

Photocatalytic degradation of toxic organic pollutants in the wastewater using dispersed semiconductor nanophotocatalysts has a number of advantages such as high activity, cost effectiveness, and utilization of free solar energy. However, it is difficult to recover and recycle nanophotocatalysts since the fine dispersed nanoparticles are easily suspended in waters. Furthermore, a large amount of photocatalysts will lead to color contamination. Thus, it is necessary to prepare photocatalysts with easy separation for the reusable application. To take advantage of high photocatalysis activity and reusability, magnetic photocatalysts with separation function were utilized. In this review, the photocatalytic principle, structure, and application of the magnetic-semiconductor nanoheterostructure photocatalysts under solar light are evaluated. Graphical abstract ᅟ.

Facile Synthesis of BiOI Nanoparticles at Room Temperature and Evaluation of their Photoactivity Under Sunlight Irradiation.

In this study, highly photoactive BiOI nanoparticles (NPs) under sunlight irradiation were synthesized by a facile precipitation method using polyvinylpyrrolidone (PVP) at room temperature. The as-prepared catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) and UV-vis diffuse reflectance spectra (UV-vis DRS). The results of XRD showed that PVP did not have any significant effect on tetragonal crystalline structure of BiOI. Also, using different amounts of PVP in the synthesis led to different morphologies and sizes of BiOI particles. It was found that using 0.2 g of PVP in the synthesis method changed morphology from 1-µm platelets to NPs with size under 10 nm. In addition, the photocatalytic performance of prepared photocatalysts was evaluated in the photodegradation of reactive blue 19 (RB19) dye under sunlight irradiation. The BiOI synthesized using 0.2 g PVP (BiOI0.2) showed higher degradation efficiency compared to BiOI prepared without any additive. Excellent visible light photocatalytic properties of nano-scaled BiOI0.2 samples compared to BiOI platelets could be attributed to higher surface-to-volume ratio and narrow band-gap energy of as-prepared BiOI0.2 NPs.

Water Dynamics and Proton-Transport Mechanisms of Nafion 117/Phosphotungstic Acid Composite Membrane: A Molecular Dynamics Study.

The use of a Nafion/phosphotungstic acid composite membrane and the impact of varying concentration of heteropoly acid (HPA) on the well-known effective mechanisms of proton transport were investigated by using classical and quantum hopping molecular dynamics simulation. Our simulations demonstrated that the HPA particles have a favorable influence on the Grotthuss mechanism in proton transportation at low hydration levels. From radial distribution function examinations, it was found that HPA particles were solvated with water and also exhibited stronger affinity toward hydronium ions. It can be concluded that addition of hydrophilic particles such as HPA improved proton conductivity. To assess this effectiveness, lifetime and half-life of the hydrogen bond (H-bond) network in the formed water clusters were investigated at different HPA concentrations. The analysis of H-bond network stability revealed that the lifetime of H-bonds between water molecules and protons decreased with increasing HPA concentration. Moreover, we found that the H-bond network between water molecules was more stable, and the mismatch between simulated bulk water and those formed water clusters in the considered systems decreased upon HPA addition. Indeed, for HPA doped membrane, the activation energy of proton transfer process from a hydronium ion to a water molecule was lower than for the undoped system. The water diffusion coefficient decreased and that of the hydronium ion enhanced with an increase in HPA doping level.

Biodegradable blend membranes of poly (butylene succinate)/cellulose acetate/dextran: Preparation, characterization and performance.

The aim of this study is to prepare biodegradable blend membranes of poly (butylene succinate) (PBS)/cellulose acetate (CA)/dextran (DEX). The effect of DEX concentration as an additive on morphology, porosity, hydrophilicity, mechanical strength, biodegradability, antifouling properties, and performance of dairy wastewater treatment of the membranes was investigated. Results demonstrated that larger pores were formed in the membrane structure and the porosity of the membranes was remarkably increased by adding DEX concentration. Moreover, contact angle was reduced up to 16% with the increase in the DEX concentration from 0 to 2wt.%. The presence of a larger amount of DEX increased the membrane degradation. Furthermore, the results of filtration tests showed that the amounts of pure water flux and permeate flux of wastewater was improved by 154% and 1543%, respectively, by increasing the additive concentration to 2wt.%. The PBS/CA/DEX membranes displayed a superior antifouling performance compared to the PBS/CA membrane.

ZnO-Nanorods as an Efficient Heterogeneous Catalyst for the Synthesis of Thiazole Derivatives in Water.

Aims & Scope: Thiazole derivatives are produced using one-pot multicomponent reactions of acid chlorides, potassium thiocyanate, amino acids, alkyl bromides and ZnO nanorods (NR-ZnO) as the catalyst in water at ambient temperature. These reactions were no't performed without using NR-ZnO as the catalyst. Nanorods of ZnO have been prepared by reflux procedure using sodium dodecylsulfate (SDS). Nanorods of ZnO showed a considerable improvement in the yield of the product and displayed significant reusable activity. MATERIALS AND METHODS: In these reactions, all chemicals were prepared from Fluka (Buchs, Switzerland). Nanorods of ZnO were synthesized in the laboratory according to literature report. By using an electrothermal 9100 apparatus, melting points of synthesized compounds were determined. Heraeus CHN-O-Rapid analyzer was employed for elemental analyses for C, H, and N. FINNIGANMAT 8430 spectrometer operating at an ionization potential of 70 eV was used for mass spectra. Shimadzu IR-460 spectrometer was employed for IR spectra. BRUKER DRX-500 AVANCE spectrometer at 500.1 and 125.8 MHz was used for 1H, and 13C NMR spectra for solutions in CDCl3 with TMS as internal standard or 85% H3PO4 as external standard, respectively. RESULTS: We describe a facile and green synthetic method for the synthesis of thiazole derivatives 5 from acid chlorides, potassium thiocyanate, alkyl bromides and amino acids using NR-ZnO- as the catalyst in water at room temperature. CONCLUSION: In conclusion, we describe an efficient, green procedure and high yielding synthesis of thiazole derivatives using acid chlorides, potassium thiocyanate, alkyl bromides and amino acids in the presence of NR-ZnO as the catalyst in water at room temperature.

Preparation of magnetic photocatalyst nanohybrid decorated by polyoxometalate for the degradation of a pharmaceutical pollutant under solar light.

Magnetic polyoxometalate nanohybrid was prepared by the surface modification of γ-Fe2O3/SrCO3 nanoparticles with PW 12 O 40 (3 -) polyoxometalate (POM) anions. The results of Fourier transform infrared (FTIR) and energy-dispersive X-ray (EDX) confirm the presence of POM on the surface of γ-Fe2O3/SrCO3 nanoparticles. TEM results revealed the ellipsoid-like structure of nanohybrid which was 23 nm in length and 6 nm in width. The activity of the photocatalyst was investigated by the photocatalytic degradation of ibuprofen (IBP) in an aqueous solution under solar light. It was found that in comparison with the γ-Fe2O3/SrCO3, the degradation of IBP after 2-h exposure to the solar light irradiation was significantly higher for POM-γ-Fe2O3/SrCO3 nanohybrids. The degradation of IBP was enhanced by the addition of H2O2 to the air saturated solution, while the addition of NaHCO3 and isopropanol restricted the degradation process. In the presence of H2O2, the Fenton photocatalyst degradation under solar light irradiation led to relatively complete degradation of IBP. Furthermore, the photocatalytic activity and magnetization properties of this magnetic photocatalyst nanohybrid provide a promising solution for the degradation of water pollutants and photocatalyst recovery. Graphical Abstract Schematic illustration for preparation of POM-γ-Fe2O3/SrCO3 nanohybrid and photocatalytic reaction of IBP on POM-γ-Fe2O3/SrCO3 nanohybrid.

Hybrid molecular simulation of methane storage inside pillared graphene.

In this study, a hybrid molecular dynamics--grand canonical Monte Carlo simulation is carried out to investigate the storage capacity of methane in a new nanostructure adsorbent called pillared graphene. This new nanostructure is composed of graphene sheets in parallel with vertical carbon nanotubes (CNTs), which act as their holders. The adsorption ability of this new structure is compared to graphene sheets to evaluate its potential for methane storage. The results show that in a specific adsorbent volume, applying pillared graphene increases the number of adsorbed methane up to 22% in comparison to graphene sheets. Given the application of various isotherm models such as Langmuir, Freundlich, Sips, and Toth and calculation of their parameters, it is predicted that methane adsorption on pillared graphene displays a heterogeneous behavior. Furthermore, the effects of geometry parameters such as CNTs diameter, the number of CNTs, and graphene sheets layer spacing on the methane uptake are investigated. The results show that the pillared graphene containing 1 CNT per 30 nm(2) graphene sheet areas provides the best configuration for methane adsorption. This optimum structure is characterized by a small diameter of about 0.938 nm and an optimal layer spacing of about 1.2 nm. Finally, our results show that this kind of pillared structure can be suitable for methane storage.

A review on catalytic applications of Au/TiO2 nanoparticles in the removal of water pollutant.

Nanomaterials are showing great potential for the improvement of water treatment technologies. In recent years, catalysis and photocatalysis processes using gold nanoparticles (Au-NPs) have received great attention due to their effectiveness in degrading and mineralizing organic compounds. This paper aims to review and summarize the recently published works and R & D progress in the field of photocatalytic oxidation of various water pollutants such as toxic organic compounds (i.e. azo dyes and phenols) by Au-NPs/TiO2 under solar, visible and UV irradiation. Extensive research which has focused on the enhancement of photocatalysis by modification of TiO2 employing Au-NPs is also reviewed. Moreover, the effects of various operating parameters on the photocatalytic activity of these catalysts, such as size and loading amount of Au-NPs, pH and calcination, are discussed. The support type, loading amount and particle size of deposited Au-NPs are the most important parameters for Au/TiO2 catalytic activity. Our study showed in particular that the modification of TiO2, including semiconductor coupling, can increase the photoactivity of Au/TiO2. In contrast, doping large gold NPs can mask or block the TiO2 active sites, reducing photocatalytic activity. The optimized loading amount of Au-NP varied for each experimental condition. Finally, research trends and prospects for the future are briefly discussed.