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Solar photocatalytic hydrogen production is considered as a potential solution to alleviate the current global energy situation. In this work, a novle CdS spherical nanoparticles/Ti3C2 MXene nanosheet (CM) heterostructure photocatalyst was prepared by in situ growth method, which has the characteristics of high efficiency and stability. The results showed that the CM sample has regular morphology and size. When compared with pure CdS, its specific surface area increased and the hydrogen evolution performance also greatly improved. Among them, the hydrogen evolution of CM-0.06 is 1295 μmol·g−1·h−1 (λ > 420 nm), which is 7 times that of spherical CdS, and it also showed stronger stability. Tight interface contact can promote the transfer and migration of photo-generated carriers, and the effective separation of electron hole pairs can enhance the absorption of visible light. In addition, Ti3C2 MXene acts as an electron trap can further accelerate the separation of photogenerated electrons and holes. The synergistic effect between semiconductor CdS and Ti3C2 MXene nanosheets, which provides a new idea for the design of more stable and efficient CdS-based photocatalysts.

In this research, a novel LaCdSe-GO-TiO2 (LCS-G-T) has been synthesized by utilizing a high powersonic method under controlled condition. From the structural morphology, it is apparent that the composite is a good example of size control and low-cost synthesis with an ultrasound and scavenger effect. The synthesized LaCdSe-GO-TiO2 (LCS-G-T) composite has given a good efficiency for photocatalytic water splitting for hydrogen evolution. The implementation of high ultrasonic power has increased, the surface area decreased the particle size, due to the collapse by micro-bubbles occurred and formation of crystal enhancement. Different characterizations have been carried out for “as-prepared” composites, such as X-ray diffraction (XRD) for checking the crystallinity, scanning electron microscopy (SEM) for structural morphology, energy-dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectra (DRS), and photoluminescence (PL) spectra, and a standard three-electrode system has been used in a cyclic voltammetry test. The LaCdSe-GO-TiO2 has exposed a good photocatalytic activity in the presence and absence of several scavengers. Moreover, the applied high powersonic for hydrogen production can significantly influence the photocatalytic activity of LaCdSe-G-T. The implemented high powersonic produces electric field bridge and helps the conversion of electron from photon.

In this investigation, 3D shaped BiVO4-GO composites have been set up with various proportions of BiVO4 by an altered hydrothermal strategy. This example is described by X-ray diffraction (XRD), Scanning electron microscopy (SEM), FT-IR, UV–Vis diffuse reflectance spectra (DRS), Raman spectroscopy, transmission electron microscopy (TEM) procedures and UV–Vis spectroscopy. BiVO4 could cover well on the outside of graphene sheets. BiVO4-GO composites with a reasonable expansion measure of BiVO4 indicated higher photocatalytic movement than plain BiVO4 toward fluid stage corruption of methylene blue (MB), texbrite BAC-L and texbrite NFW-L under obvious light illumination.

The potential application of MoS2 as a potential H2 precipitation photocatalyst has received widespread attention and is considered a promising alternative to precious metal cocatalysts due to its richness and low cost. However, the catalytic active center of MoS2 is only along the edge of the MoS2 layer. Both theoretical and experimental studies have shown that defect engineering can increase the active site of MoS2 and has superior activity in catalytic reactions. Therefore, this review describes the nature, defect types, and preparation of defective MoS2. Due to the recombination of MoS2 and semiconductor has specific interface characteristics, Schottky heterojunctions can provide accelerated charge separation and lower Schottky barriers for photocatalytic applications, they are effective photocatalysts. Therefore, the preparation of the defect MoS2-supported semiconductor photocatalyst and its application in the photocatalytic water splitting reaction are also introduced. This article’s profound understanding of defects can consolidate basic photocatalysis theory and provide new insights for the rational design of satisfactory defect engineering photocatalytic materials.

A facile microwave assisted solvothermal process is designed for fabricating SnS nanoparticles decorated on graphene nanosheet, which used as visible light driven photocatalyst. Some typical characterization techniques such as XRD, FT-IR, SEM with EDX analysis, and TEM and BET analysis are used to analyse the physical characteristics of as-prepared samples. Spherical SnS nanoparticles are uniformly dispersed on the surface of graphene nanosheet due to ammonia, which can prevent the aggregation of graphene oxide. Meanwhile, microwave radiation provides fast energy that promotes the formation of spherical SnS nanoparticles within a short time. The visible light photocatalytic activity of as-prepared SnS-GR nanocomposites is analysed through photodegradation efficiency of methylene blue with high concentration. According to the higher photocatalytic property, the as-prepared SnS-GR nanocomposites can be expected to be an efficient visible light driven photocatalyst. After five cycles for decolorization, the rate decreases from 87 % to 78 % (about 9 %). It is obvious that the photocatalytic activity of SnS-GR nanocomposite has good repeatability.

Reducing CO2 into high value fuels and chemicals is considered a great challenge in the 21st century. Efficiently activating CO2 will lead to an important way to utilize it as a resource. This article reviews the latest progress of g-C3N4 based catalysts for CO2 reduction. The different synthetic methods of g-C3N4 are briefly discussed. Article mainly introduces methods of g-C3N4 shape control, element doping, and use of oxide compounds to modify g-C3N4. Modified g-C3N4 has more reactive sites, which can significantly reduce the probability of photogenerated electron hole recombination and improve the performance of photocatalytic CO2 reduction. Considering the literature, the hydrothermal method is widely used because of its simple equipment and process and easy control of reaction conditions. It is foreseeable that hydrothermal technology will continue to innovate and usher in a new period of development. Finally, the prospect of a future reduction of CO2 by g-C3N4-based catalysts is predicted.

Photocatalytic CO2 reduction into hydrocarbon fuels over photocatalysts has hypothetical and reasonably developed into a trendy exploration topic. In this study, the progress of the quaternary nanocomposite containing a graphene-based catalyst was reported; this was fabricated using the hydrothermal technique. The analysis of physical characteristics of the nanocomposite confirmed the interaction between all parts. The quaternary nanocomposite containing the graphene-based catalyst was utilized for carbon dioxide reduction to methanol (CH3OH) under light irradiation. Titanium dioxide (TiO2) and the quaternary nanocomposite of AgCuInS2 were monotonously spread on the graphene exterior. This nanomaterial showed superior activity compared with TiO2 and the binary composite for CO2 conversion, and the obtained result indicates that the synthesized ternary composite enhaces the properties of the photocatalyst in the reduction process.

In this work, a carbon-doped carbon nitride photocatalyst is successfully synthesized through a simple centrifugal spinning method after heat treatment. The morphology and properties of the prepared photo catalyst are characterized by Xray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis spectrophotometer (UV-vis), and specific surface area. The results show that the band gap of the prepared sample, g-CN-10 is 2.1 eV, is significantly lower than that of pure carbon nitride, 2.7 eV. As the amount of cotton candy increased, the absorption capacity of the prepared catalyst for visible light is significantly enhanced. In addition, the degradation efficiency of Rhodamine B (RhB) by sample g-CN-10 is 98.8 % over 2h, which is twice that value of pure carbon nitride. The enhancement of photocatalytic ability is attributed to the increase of specific surface area after the carbon doping modifies carbon nitride. A possible photocatalytic degradation mechanism of carbon-doped carbon nitride is also suggested.

Novel BiOCl/g-C3N4 thin film photocatalysts were synthesized via a simple two-step spin coating method. The prepared photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, and ultraviolet–visible spectroscopy. The photocatalytic activity of the thin films for the degradation of rhodamine B under visible light (λ ≥ 400 nm) was investigated. The results showed that the BiOCl/g-C3N4 thin film photocatalysts exhibited significantly improved visible light absorption compared to the pure BiOCl thin film. The BiOCl/g-C3N4 film showed a rhodamine B degradation efficiency of 81.0% under visible light, which is 23.8 times higher than that of the pure BiOCl thin film. This excellent photocatalytic activity of the BiOCl/g-C3N4 film can be attributed to its efficient electron–hole separation due to the presence of g-C3N4.

The present study reported biofabrication of flower-like SnO2 nanoparticles using Pometia pinnata leaf extract. The study focused on the physicochemical characteristics of the prepared SnO2 nanoparticles and its activity as photocatalyst and antibacterial agent. The characterization was performed by XRD, SEM, TEM, UV-DRS and XPS analyses. Photocatalytic activity of the nanoparticles was examined on bromophenol blue photooxidation, meanwhile, the antibacterial activity was evaluated against Klebsiella pneumoniae, Escherichia coli Staphylococcus aureus and Streptococcus pyogenes. XRD and XPS analyses confirmed the single tetragonal SnO2 phase. The result from SEM analysis indicates the flower like morphology of SnO2 nanoparticles, and by TEM analysis, the nanoparticles were seen to be in uniform spherical shapes with a diameter ranging from 8 to 20 nm. SnO2 nanoparticles showed significant photocatalytic activity in photooxidation of bromophenol blue as the degradation efficiency reached 99.93%, and the photocatalyst exhibited the reusability as the degradation efficiency values were insignificantly changed until the fifth cycle. Antibacterial assay indicated that the synthesized SnO2 nanoparticles exhibit an inhibition of tested bacteria and showed a potential to be applied for further environmental and medical applications.

Copper oxide (CuO) nanoparticles (NPs) were decorated on reduced graphene oxide (rGO) through the effective synthetic route method. Powder X-ray diffraction, Fourier transform infrared, ultraviolet-visible absorption, and scanning electron microscopy techniques were used to analyze the chemical structure, functional groups, absorbance, and morphology. Under visible light illumination, the CuO/rGO nanocomposites have higher catalytic activity compared to the bare CuO NPs which were suitable for degradation of methylene blue (MB) and Congo red (CR) dyes. According to the findings, the CuO/rGO nanocomposites possess excellent photocatalytic efficiency. Thus, the synthesized CuO/rGO nanocomposite is a promising photocatalyst for the deterioration of organic pollutants in water and wastewater treatment.

The present study deals with the synthesis, characterization, and testing of photocatalytic activity towards the degradation of organic dyes and for that, nitrogen-rich graphitic carbon nitride/cuprous oxide (g-C3N4@Cu2O) composite was synthesized with improved photocatalytic performance using the hydrothermal method. For the characterization of composite, many different techniques are employed such as Fourier transform infrared spectroscopy for the chemical functionality and bonding, diffused reflectance ultraviolet-visible spectroscopy for the optical properties, powdered X-ray diffraction patterning for the phase purity and crystal orientations, field emission scanning electron microscopy for the surface morphology, thermogravimetric analysis for the thermal stability, and dynamic light scattering spectroscopy for the zeta-potentials. On testing, we observed significant effects of photocatalytic activity in terms of the degradation of various dyes like methylene blue, rhodium-B, thymol blue, and blue ink solution under the UV light irradiation using 8 W xenon lamp. Such a significant activity of the composite can be linked to the increased light absorption, charge separation efficiency, and specific surface area as indicated by the UV–vis DRS analysis. Further, the mechanistic analysis confirmed the active role played by the holes (h+) and superoxide radicals (·O2−) for photocatalytic dye degradation.

In this study, we describe the structure of bismuth vanadate (BiVO4)/graphene oxide/polyaniline (PANI) compound with exploited interfacial coupling, their use as visible-light photocatalysts and safety property. Thin graphene oxide sheets could completely cover BiVO4 polyhedrons with vastly conductive polymer PANI through an evaporation-induced hydrothermal process. The enhanced surface adsorption outcome of GO, a huge improvement in the photoactivity of BiVO4, has been proved through the degradation of methylene blue (MB) and safranin O (SO) upon the covering of polyaniline. The improved photocatalytic activity is recognized for the development of well-defined BiVO4/GO/PANI interfaces which considerably increases the charge separation efficacy. Conversely, safety aspects are investigated for identifying the toxicity of samples on the different kinds of bacteria. Our study found that in the existence of every sample the bacteria could not be killed throughout the culture medium. Considering its ease of preparation and excellent performance, BiVO4/GO/PANI could be a promising, competitive and safe visible-light-driven photocatalyst in the field of environmental remediation.

Various combinations of mesoporous silica and cadmium oxide–graphene have been prepared using a self-assembly method under catering of cetyltrimethylammonium bromide (CTAB) as the surfactant template at ambient conditions. The structural and optical properties of the obtained nanocomposites were investigated by many different techniques. The results of photocatalytic measurements revealed that almost 100% of MB organic dye was removed with the presence of SiO2/CdO–graphene composite under visible light irradiation. Moreover, the initial pH also plays an important role in the photodegradation processes. On the other hand, this work opens a way to enhance the photocatalytic activity of gallic acid at ambient condition without any further different oxidation processes. From the evolutionary aspect, SiO2/CdO–graphene composite revealed better H2 generation than that of binary photocatalyst (CdO–graphene nanocomposite). The results of characterization and photodegradation suggest that SiO2/CdO–graphene material constitutes a new photocatalyst for the degradation of organic contaminants, as well as the development of an efficient hetero-system for hydrogen production.

Progressive WO3-G composites with various WO3 contents were prepared using an easy CVD method, and showed notably enhanced visible-light driven photocatalytic H2 - evolution activities, wit...

In this study, we describe the special properties of LaNiSbWO4-G-PANI (LNSWGP) polymer composites with exploited interfacial coupling and their use as visible light photocatalysts. These quaternary composites are newly designed materials by easiest hydrothermal method. Thin graphene (G) sheets could completely cover LaNiSbWO4 (LNSW) with highly conductive polyaniline by means of an evaporation-induced hydrothermal process. The increased surface adsorption outcome of G, a huge improvement of the photoactivity of LNSW, has been proved by the degradation of anionic methylene orange (MO) and trihydroxybenzoic acid (a type of phenolic acid) upon the covering of polyaniline. The improved photocatalytic activity is recognized as developing from the well-defined LNSWGP interfaces, which considerably increase the charge-separation efficacy. The efficiency of degradation was obtained MO (85%) & trihydroxybenzoic acid (92%). Our study found that the photocatalytic performance of LNSWGP in the existence of polymer was better than that of any other composite in an aqueous medium. Considering its ease of preparation and excellent performance, LNSWGP could be a promising, competitive, and safe visible-light-driven photocatalyst in the field of battery separators, solar cells, and environmental remediation.

Novel nano needle-like Cu2O-GO-TiO2 (Cu2OGT-A) and CuO–GO-TiO2 (CuOGT-B) composites with superior photocatalysis were successfully synthesized via a self-assembly process at a low temperature. The structural and morphological characterizations of the synthesized compounds were analyzed using a series of analytical techniques. The photocatalyst showed excellent activity under visible light and was used for the photodegradation of safranine O (SO), reactive black B (RBB), and gallic acid (GA) as target anionic and cationic pollutants. The removal capacity of CuOGT-B is slightly higher than that of Cu2OGT-A, and the removal rates of SO, RBB, and GA reach up to 82.91%, 81.51%, and 83.87%, respectively. Furthermore, the excellent morphologies of Cu2OGT-A and CuOGT-B composites, e.g., needle-like structure, monodisperse, and graphene sheets drastically improve their dispersion in solution, light harvesting, charge separation and transportation, which might do some contributions to improve their photocatalytic activities accordingly. The Cu2OGT-A and CuOGT-B prepared under the conditions reported herein could be promising materials in water purification.

In this study, mesoporous CdO–graphene and mesoporous TiO2 were successfully synthesized using a facile method. The results indicated that photocatalytic activity can be enhanced with the combinati...

This work presents a combination of mesoporous CuO-graphene and mesoporous TiO2 materials, using a hydrothermal method at low temperature. The photocatalytic activity was evaluated for organic dyes decomposition. The high photocatalytic rate is mainly due to the high photogenerated electron-holes transport properties, as well as the mesoporous structure of the as-obtained CuO-graphene-TiO2 photocatalyst. The as-prepared materials were characterized by XRD, nitrogen adsorption/desorption isotherms, SEM, EDX, TEM, HR-TEM, XPS, DRS, and Raman analysis. The highest photocatalytic activity of RBB organic dyes is mainly due to the large adsorption capacity of the as-obtained CuOGT material, as well as the high separation efficient of the photogenerated e—h+ pairs. The as-prepared mesoporous CuO-graphene-TiO2 material is a promising candidate for enhancing the photocatalytic performance of organic dyes, phenol compounds, and industrial wastewater.

A novel non-toxic hybrid BiVO4-GO-TiO2-polyaniline (PANI) (BVGT-PANI) composite with superior photocatalysis was successfully prepared via a one-pot hydrothermal reaction. The structural and morphological characterizations of the synthesized compounds were analyzed by a series of techniques. We found excellent photocatalytic efficiencies for methylene blue (MB) and phenol degradation under visible light irradiation after adhering the PANI to the photocatalyst. The degradation rates of MB and phenol reach up to approximately 85% and 80%, respectively, after 3 h of irradiation. For photodegradation MB, BVGTA exhibit the highest kapp rate constant of about 1.06 × 10−2 min−1, which is about 1.63-fold faster than BVG and 2.94-fold faster than BVGT. For photodegradation of phenol, BVGTA exhibits the highest kapp rate constant, of about 8.86 × 10−3min−1, which is about 1.2-fold faster than BVG and 1.96-fold faster than BVGT. Furthermore, vitro toxicity test against Bacillus subtilis and Staphylococcus aureus demonstrated that the nanophotocatalyst is non-toxic.

The new novel ternary mesoporous SiO2/CdInSe-graphene composites with diameters of approximately 8.08 nm have been fabricated through a self-assembly method. All physical tests demonstrated that the CdInde-graphene was successfully uniformly distributed onto the surface of the ordered mesoporous silica particles. The obtained mesoporous SiO2/CdInSe-graphene composites exhibited good photocatalytic activity for degradation of both cationic-anionic organic dye groups, as well as the decomposition of the representative phenol group of the compound under visible light irradiation. Moreover, the photocatalytic evolution of hydrogen was studied for establishing a wider application of the as-fabricated SiO2/CdInSe-graphene catalyst in the case of energy conversion. This work indicated that the combination of the mesoporous silica and CdInSe-graphene enables achievements such as an enhancement photocatalytic performance, which has potential in industrial waste management and energy conversion.

To promote outstanding qualities of mesoporous silica and enhance photocatalytic activity of CdSe and silica nanoparticles, the combination of SiO2 nanoparticles from silica precursor with CdSe-graphene nanoparticles was processed under catering of cetyltrimethylammonium bromide (CTAB) and sodium lauryl sulfate (SLS) as the surfactant template. The as-synthesized sample exhibited highly efficient photocatalytic effects for treatment of MB and RBB organic dye solutions at optimum conditions for this study, including pH and catalyst dosage, were at pH 11 for MB dye solution case and pH 3 for RBB dye solution case and initial amount was 0.05 g catalyst for both cases. Besides, hydrogen generation of SiO2/CdSe-graphene was markedly higher than that of binary CdSe-graphene nanocomposite under ambient conditions with/without methanol 20% sacrificing reagents at room temperature. The SiO2/CdSe-graphene nanocomposite is capable of photocatalytic degradation of different organic dyes under visible light irradiation as well as for developing efficient hetero-system for hydrogen production.

A combination of mesoporous silica with an LaCuS2-graphene composite has been prepared by a self-assembly method in support of the CTAB surfactant as the structure creator and basic medium. The characterization was investigated using XRD, SEM, TEM, HR-TEM, EDS, XPS, Raman, and DRS analysis. The pore size of the as-fabricated composite was calculated to be 5.83 nm by the nitrogen adsorption/desorption isotherms. In addition, the photocatalytic properties revealed that the mesoporous SiO2/LaCuS2-graphene catalyst presented a good result for the photocatalytic activity of organic dyes and gallic acid under visible light irradiation. Moreover, the as-prepared mesoporous SiO2/LaCuS2-graphene nanocomposite exhibited a good photodegradation rate for a cationic organic dye group under a pH medium of 11. The photocatalytic performance of the phenol compound representation presented a good result, and the optimum amount of the catalytic for the gallic acid photocatalytic activity is 0.05 g. In addition, the mesoporous SiO2/LaCuS2-graphene catalyst can be exploited for the application of solar energy conversion with high hydrogen production capacity.

This work reports a self-assembly method for preparing a composite of Bi2WO6-graphene and ordered mesoporous to form a novel ternary SiO2/Bi2WO6-graphene material. The successful synthesis was confirmed by physical tests such as XRD, SEM, TEM, EDX, XPS, DRS, Raman, and Galvano cyclic voltammetry. Moreover, the mesoporous structure of the obtained material was demonstrated by nitrogen adsorption/desorption isotherms. The investigations imply that the Bi2WO6-graphene composite was grown on an ordered mesoporous structure of the silica in a basic medium and the structure was modified with a cetyltrimethylammonium bromide surfactant. The photocatalytic activity was investigated in terms of photodegradation of cationic-anionic organic dye groups and the photocatalytic performance of gallic acid under visible light irradiation. The achieved results showed that the ternary SiO2/Bi2WO6 catalyst holds promise to become a new potential photocatalyst for the enhancement of photocatalytic activities.

BiVO4-GO-PVDF (PVDF = Polyvinylidene Difluoride) photocatalyst is successfully synthesized by ultrasonication method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. Morphology of BiVO4-GO-PVDF looks like a human embryo embedded inside an amniotic sac. Photocatalytic performance of BiVO4-GO-PVDF for decolorization of methylene blue is investigated. BiVO4-GO-PVDF system reveals enhanced photocatalytic activity degradation of methylene blue (MB), Rhodamine B (RhB) & Safranin-O (SO) in water under visible light irradiation as compared to the pure BiVO4 catalyst, BiVO4 & PTFE decorated on the graphene sheet. The experimental result reveals that the covering of graphene sheets in this composite catalyst enhances photocatalytic performance under visible light. This enhanced activity is mainly attributed to effective quenching of the photogenerated electron-hole pairs confirmed by photoluminescence spectra. Trapping experiments of radicals and holes were conducted to detect reactive species generated in the photocatalytic system, experimental results revealed that direct hole oxidation reaction is obviously dominant during photocatalytic reactions on the BiVO4-GO-PVDF system.

Here, we report the new ternary composite Bi2O3–G–ZnO using ultrasonic techniques as well as X-ray diffraction (XRD), scanning electron microscopy (SEM), high transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and UV–Visible diffuse-reflectance spectra (DRS) analyses. The prepared photocatalysts were tested for the CO2 photocatalytic reduction in a reactor, and the main detected reaction product is CH3OH. The optimum loading graphene of 8% exhibited the maximum photoactivity, achieving a total CH3OH yield of 7.250 µmol g−1 h−1 after 48 h. This excellent photoreduction activity is due to the positive synergistic relation between the Bi2O3 and the graphene components in our heterogeneous system. The present work provides a novel application regarding the improvement of nanoscale Bi2O3–G–ZnO materials for photocatalytic applications.

In the present work, we report the development of a WSe2-Graphene-TiO2 ternary nanocomposite via ultrasonic techniques and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The band-gap of the WSe2-Graphene-TiO2 was estimated to be about 1.62 eV which is suitable for photodegradation process under under ultraviolet UV/Visible light irradiation. The photocatalytic potential of nanocomposites is investigated for CO2 reduction to CH3OH. WSe2-G-TiO2 with an optimum loading of graphene of 8 wt% showed the high photoactivity, gaining a total CH3OH yield of 6.3262 µmol g−1 h−1 after 48 h. This excellent photoreduction activity is owing to the progressive synergistic relation between WSe2/TiO2 and graphene components in our heterogeneous system.

A facile and eco-friendly self-assembly method for combining mesoporous silica with Cu 2 O-graphene composite with a nonionic surfactant Pluronic® P123 is proposed. The achieved nanocomposites were characterized via X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms using the BET and BJH method, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV–vis DRS), X-ray photoelectron spectroscopy (XPS), and FT-IR spectra. The photocatalytic degradation of safranine O (SO), texbrite BA-L (TBA), texbrite NFW-L (TNFW), and texbrite BAC-L (TBAC) organic dyes in an aqueous solution under visible light irradiation with the difference of initial pH and catalyst dosage was observed via UV spectrophotometry, after measuring the decrease in their concentrations. Two factors of the excellent photocatalytic activity of the mesoporous SiO 2 /Cu 2 O-graphene composite made a significant impression: the adsorption capacity due to the mesoporous structure (a result of the pore diameter, pore volume, and large surface area), and the decomposition effect through catalysis. Recycling experiments that were also carried out proved the good stability of the survey samples. The combination of mesoporous SiO 2 with 10% Cu 2 O-graphene nanocomposite (by weight) is expected to become a new generation material for photodegradation with excellent performance.

In the present study, we have evaluated the gas sensing and photocatalytic activity of reduced graphene oxide (rGO) conjugated titanium dioxide (TiO2) nanoparticles (NPs) formed by the hydrothermal method. The as-synthesized rGO-TiO2 nanocomposite were characterized for the physicochemical properties such as the nature of crystallinity, functionalization, and morphology by making use of the powder X-ray diffraction, Fourier transform-infrared spectroscopy, and scanning electron microscopy, respectively. On testing the gas sensing properties, we found that the rGO-TiO2 nanocomposite can serve as the chemoresistive-type sensor because of its sensitivity and selectivity towards different concentrations of hydrogen and oxygen at room temperature conditions. However, the rGO-TiO2 sensor’s response and recovery speed towards hydrogen and oxygen needs further optimization. Test of photocatalytic activity of TiO2-rGO catalyst for the removal of two model contaminant dyes, RhB and MB showed effective removal, with respective degradation percentages of about 80 and 90% within the first 50 min of irradiation under visible light irradiation. Besides, MB was more effectively degraded using TiO2-rGO than pure TiO2 during the first 30 min of irradiation and this enhanced activity can be attributed to the increased capacity of light absorption, the efficiency of charge carriers separation, and the specific surface area maintained by the rGO-TiO2 nanocomposite to effectively utilize the photo-generated holes (h+) and superoxide radicals (O2− ), responsible for the degradation of the dye. Based on the overall analysis, the formation of rGO-TiO2 nanocomposite can significantly improve the gas sensing and photocatalytic properties of TiO2 NPs and thus can be potential for practical applications in future nanotechnology.

A new structure of graphene-Mg2CuSnCoO6 composite bridged with gallic acid (GMG) was synthesized with a novel method. Band gap energy of the newly synthesized nanocomposite was evaluated with a laser-wavelength region and DRS method. Evaluation and analysis were based on the relationship among XRD, HRTEM, XPS, Raman scattering , and computer simulated model structure. Changes in the structure of graphene or graphene-based composite were associated with location changes of the valence band and the conduction band . Electron density was used to confirm the number of electrons by computer simulation. Finally, such graphene-Mg 2CuSnCoO6-gallic acid nanocomposite was used for photocatalytic CO2 reduction into methanol. Under UV-light irradiation, the highest methanol yield was 5.576% with 0.6 g of scavenger. This work might offer a promising strategy for measuring band gap energies of different types of semiconductors.

The present work deals with the development of a new ternary composite, $$\hbox {Ag}_{2}\hbox {Se}$$ – $$\hbox {G}$$ – $$\hbox {TiO}_{2}$$ , using ultrasonic techniques as well as X-ray diffraction (XRD), scanning electron microscopy (SEM), high transmission electron microscopy (HTEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and UV–Vis diffuse reflectance spectra (DRS) analyses. The photocatalytic potential of nanocomposites is examined for $$\hbox {CO}_{2}$$ reduction to methanol under ultraviolet (UV) and visible light irradiation. $$\hbox {Ag}_{2}\hbox {Se}$$ – $$\hbox {TiO}_{2}$$ with an optimum loading graphene of 10 wt% exhibited the maximum photoactivity, obtaining a total $$\hbox {CH}_{3}\hbox {OH}$$ yield of 3.52 $$\upmu \hbox {mol}\,\hbox {g}^{-1}\,\hbox {h}^{-1}$$ after 48 h. This outstanding photoreduction activity is due to the positive synergistic relation between $$\hbox {Ag}_{2}\hbox {Se}$$ and graphene components in our heterogeneous system.

A novel material, frost-like CuO combined-graphene-TiO2 composite, was successfully synthesized using a self-assembly method. During the reaction, the loading of CuO and TiO2 nanoparticles on graphene sheets was achieved. The obtained CuO-graphene-TiO2 composite photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), and X-ray photoelectron spectroscopy (XPS). The frost-like CuO nanoparticles combined with the small TiO2 rods were successfully loaded on the transparent graphene sheets. The photocatalytic degradation of rhodamine B (RhB), methylene blue trihydrate (MB), and reactive black B (RBB) in an aqueous solution under visible light irradiation was observed by UV spectrophotometry after measurement of the decrease of their concentrations. Through the photocatalytic test and TOC results, the CuO-graphene-TiO2 is expected to become a new potential material for photodegradation activity with excellent photodegradation. The scavenging experiments confirmed that OH and h+ play a major role in the photocatalytic reaction than O2 − or both hydroxyl and holes are the active species responsible for the RBB degradation under visible light irradiation. After five repeated cycles to investigate the stability of photocatalytic performance, the CuO-graphene-TiO2 had high stability under visible light irradiation.

A BiVO4-GO-PTFE photocatalyst was prepared by a facile one-step hydrothermal method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, UV–Vis spectroscopy, and transmission electron microscopy techniques. The results showed that bulk monoclinic needle-like BiVO4 and poly-tetrafluoroethylene (PTFE) nanoparticles with a uniform size distribution could be loaded on graphene oxide (GO) sheets to facilitate the transport of electrons photogenerated in BiVO4, thereby reducing the rate of the recombination of the photogenerated charge carriers in the coupled BiVO4-GO-PTFE (BGP) composite system. PTFE nanoparticles were dispersed on the surface of the GO sheets, which exhibited a localized surface plasmon resonance phenomenon and enhanced visible light absorption. The removal efficiency of dye (MB, RhB, RBB) by (BiVO4-GO-PTFE-30%) BGP-30% (90%) was much higher than that by BGP-25% (85%), BGP-15% (76%), and BGP-10% (64%) under visible light irradiation. Recycle experiments showed that the composite still presented significant photocatalytic activity after five successive cycles. Finally, we propose a possible pathway and mechanism for the photocatalytic degradation of dyes using the composite photocatalyst under visible light irradiation.

The microwave-assisted synthesis of graphene-Bi 8 La 10 O 27 -Zeolite (G-Bi 8 La 10 O 27 -Z) nanocomposite is reported here for the first time. In this investigation, a novel route is taken for the synthesis, interaction, kinetics, and mechanism of a hybrid G-Bi 8 La 10 O 27 -Z nanocomposite using a microwave-assisted method. The photocatalytic activities of the as-obtained catalysts were assessed based on the degradation of Rhodamine B (RhB), Methylene Blue (MB), and Texbrite (TXB) under visible light irradiation. The results show that the G-Bi 8 La 10 O 27 -Z nanocomposite exhibited more stable photoresponse degradation performance under the Visible light radiation than pure G-Bi 8 La 10 O 27 -Z; and that the synthesized G-Bi 8 La 10 O 27 -Z can be used as a high performance catalyst for dye wastewater. The detailed photocatalytic mechanism of the photodegradation process is also discussed.

The degradation of methyl blue (MB) catalyzed by platinum (Pt)-graphene/TiO₂ in dark ambiance was studied. Pt–graphene/TiO₂ composites were prepared by simple hydrothermal method. Characterizations of composites were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) analysis, and energy dispersive X-ray (EDX) analysis. UV-spectroscopic analysis of the dyes was performed by measuring the change in absorbance. The degradation of the organic dyes was calculated based on the decrease in concentration of the dyes with respect to regular time intervals. Rate coefficients for the catalytic process were successfully established and reusability tests were performed to test the stability of the used catalysts.

In the present study, we have evaluated the photocatalytic potentials of ceria (CeO2) loaded graphitic carbon nitride (GCN; g-C3N4) composite towards the degradation of two different organic dyes. The CeO2/GCN composite following its formation by the co-precipitation route, the physicochemical properties like crystallinity, functionality, optical, and morphology are being studied using various instrumental techniques such as powdered X-ray diffraction (XRD), Fourier transforms–infrared spectroscopy (FTIR), UV–Vis diffuse reflection spectroscopy (UV–Vis), and field emission scanning electron microscopy (FESEM). From the analysis, the XRD studies indicated that the composite has the cubic structure of ceria and hexagonal phase for the GCN. The FTIR analysis supported for the successful formation of CeO2/GCN composite and UV–Vis provided the optical properties indicated to have the bandgap energy values of 3.12 and 2.86 eV for pure CeO2 and CeO2/GCN composite (respectively). Also, the FESEM confirmed for the surface morphology of CeO2/GCN composite, and finally, the test of photocatalytic activity studied in the presence of visible light irradiation towards the degradation of Methyl blue (MB) and Rhodamine-B (Rh-B) dyes indicated for the superior activity of CeO2/GCN composite as compared to the single-phase GCN and pure CeO2. Based on the cumulative analysis of results, it can be informed that the CeO2/GCN composite can be useful for the sustainable means of degradation of organic dyes (MB and Rh-B) by taking advantage of the synergistic impact of the two components of CeO2 and GCN.

In this research, we synthesized a quaternary composite containing a graphene-based LaYAgO4-Graphene-TiO2 nanocomposite using a hydrothermal method. We examined all prepared samples by means of physical techniques, such as XRD, SEM-EDX, HRTEM, XPS, Raman, and DRS. We tested the photocatalytic activity of the ternary composite for CO2 reduction in a reactor using commercial carbonated water, and the target product was methanol (CH3OH), detected under UV and Vis light irradiation. The ternary nanocomposite, which contains three times a quaternary composite (LaYAgO4), exhibited high photocatalytic activity and improved a sum total of methanol of 12.27% after 48 h reaction time. In a heterogeneous system, the relevance between the Graphene-TiO2 and LaYAgO4 components showed an excellent photoreduction efficiency. This heterojunction presented herein offers a promising route for the rational design of a new class of photocatalysts for various applications in environmental protection and solar-energy conversion.

TiO₂/BiVO₄ layered films were prepared by sol-gel and spin coating methods. X-ray diffraction (XRD), scanning electron microscopy (SEM) and Uv-vis spectroscopy were used to investigate the crystal structure, morphology and ultraviolet-visible absorption of the TiO2/BiVO₄ films. The photocatalytic activity of the prepared films was inspected according to the degradation of methylene blue. The results show that the prepared films present a net chain structure; the absorption band edge had obvious red shift. The degradation of the methylene blue solution was about 80% after 300 mins using TiO₂/BiVO₄ layered films under visible light, which was stronger than when using only pure TiO₂ film and BiVO₄ film.

Here, we examined the photo-degradation efficiency of Cu2Se-graphene nanocomposites synthesized by a facile and fast mi- crowave-assisted technique. The prepared composites were characterized by X-ray diffraction (XRD), scanning electron micro- scopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, XPS and UV-Vis spectrophotometry. The photo- catalytic performance was studied through the decomposition of Rhodamine (Rh B) as a standard dye under visible light radiation. A 95% of Rh B degradation after visible light irradiation for 180 min indicates that the Cu2Se-graphene composite exhibited significant photodegradation efficiency. Therefore, it can be concluded that the synthesized Cu2Se-graphene can be used as a suitable catalyst for decomposing dye pollutants.

This paper introduced one pot method for the synthesis of hybrid CdLa2S4-graphene/TiO2 nanocomposite. The surface properties seen by SEM present a characterization of the texture on CdLa2S4-graphene/TiO2 composites and showed a homogenous composition in the particles. The EDX spectra for the elemental identification showed the presence of C, O and Ti with strong Cd, La and S peaks for the CdLa2S4-graphene/TiO2 nanocomposite. The generation of reactive oxygen species were detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). It is found that the photocurrent density and the photocatalytic effect increase in the case with the modified CdLa2S4.From the photocatalytic results, the excellent activity of CdLa2S4-graphene/TiO2 nanocompositefor degradation of methylene blue (MB) and Texbrite BA-L (TBA) undervisible irradiation could be attributed to both the effects between photocatalysis of the supported TiO2 and charge transfer of the grapheme nanos...

Photocatalytic reduction of CO2 over a Cu2Se–graphene nanocatalyst has been investigated. The nanocomposite material was successfully prepared via a modified hydrothermal method. The structure and properties of the prepared composite were characterized by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray microscopy, transmission electron microscopy, Raman spectroscopic analysis, and X-ray photoelectron spectroscopy. A synergetic effect of the combination of Cu2Se and graphene appeared in the form of excellent photocatalytic reduction capability of CO2. The photocatalytic efficiencies of the samples were characterized by testing for the photoreduction of CO2 to alcohol under visible light irradiation, which produced results such as to suggest that there is a significant potential for graphene-based semiconductor hybrid materials to be used as photocatalysts for reduction of CO2.

Visible light-responsive ZnO-graphene-TiO 2 (ZGT) composite catalyst was successfully synthesized via a simple solvothermal process. The intrinsic characteristics of as-obtained samples were examined using a variety of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The band gap energies of the samples were evaluated by UV–vis diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activities of as-obtained catalysts were assessed based on the degradation of rhodamine B (RhB), texbrite BAC-L (TBAC) and texbrite NFW-L (TNFW) under visible-light irradiation. ZGT exhibited higher visible-light-activated photocatalytic activity than did other samples (ZGT (7.97 × 10 −4 min −1 ) > ZG (3.43 × 10 −4 min −1 ) > graphene (2.43 × 10 −4 min −1 ) > TiO 2 (2.22 × 10 −4 min −1 ) > ZnO (1.87 × 10 −4 min −1 )). In addition, ZGT showed higher enhanced photocatalytic degradation of RhB than did other dyes (RhB (7.97 × 10 −4 min −1 ) > TNFW (5.20 × 10 −4 min −1 ) > TBAC (2.48 × 10 −4 min −1 )). It is therefore evident that the synthesized ZGT can be used as a high performance catalyst for dye wastewaters. Moreover, the detailed photocatalytic mechanism of the photodegradation process is discussed.

Manganese and TiO₂ grown on Activated Carbon Fiber (ACF) was synthesized by hydrothermal method. The prepared composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX). The catalytic behavior was investigated through the decomposition of methylene blue (MB) and methyl orange (MO) as standard dyes under visible light. The degradation performance of the degraded standard dye solutions was determined by UV-Vis spectrophotometry. This enhanced photocatalytic activity arises from the positive synergetic effect among the Mn, TiO₂ and ACF in this heterogeneous photocatalyst. The process contributes to the release of abundant photocatalytic sites of Mn and TiO₂ and improves the photocatalytic efficiency. The excellent adsorption and photocatalytic effect with the explanation of the synergetic mechanism are very useful not only for fundamental research but also for potential practical applications.

Pd-Pt/graphene-TiO2 nanocomposites were synthesized via a facile ultrasonic and hydrothermal method. For the functionalization of graphene, large area graphene obtained by chemical vapor deposition method was oxidized by 3-chloroperoxybenzoic acid. The functionalized graphene oxide was decorated with TiO2. And then, Pt and Pd nanoparticles were dispersed on graphene surface, simultaneously. The characterizations of “as-prepared” samples were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), Raman, specific surface area (BET) and with energy dispersive X-ray (EDX). The photocatalytic activity of the Pd-Pt/graphene-TiO2 nanocomposite catalyst was evaluated by H2 evolution under UV light. Pd-Pt/graphene-TiO2 (Pd-Pt/G-TiO2) exhibited higher photocatalytic activities than control experimental group samples (TiO2, G-TiO2, Pd/G-TiO2 and Pt/G-TiO2) under UV light irradiation.