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The human chorionic gonadotropin (hCG) hormone is a biomarker that can predict tumors and early pregnancy; however, it is challenging to develop sensitive qualitative-quantitative procedures that are also effective, inventive, and unique.

A one-step sol–gel method for SrSnO3 nanoparticle synthesis and the incorporation of multi-walled carbon nanotubes (MWCNTs) to produce a SrSnO3@MWCNT photocatalyst is presented. The incorporation of MWCNTs results in enhancement of structural, optical, and optoelectrical properties of SrSnO3. The optimized 3.0% addition of MWCNTs results in light absorption enhancement and a reduction of the band gap from 3.68 to 2.85 eV. Upon application of the photocatalyst in the photocatalytic hydrogen production reaction, SrSnO3@MWCNT-3.0% yields 4200 μmol g–1 of H2 in just 9 h with the use of 1.6 g L–1 of the photocatalyst. SrSnO3@MWCNT exhibits remarkable chemical and photocatalytic stability upon regeneration. Enhanced photocatalytic ability is attributed to improved surface properties and charge-carrier recombination suppression induced by the MWCNT addition. This study highlights the remarkable improvements in chemical and physical properties of semiconductors with MWCNT incorporation.

This contribution reports the synthesis of mesoporous X% Nd2O3 modified ZnO (X = 1, 2, 3 and 4) during sol-gel process in existence of Pluronic F-108 for the first time. XRD indicated the construction of hexagonal ZnO nanocrystals and the isotherms exhibited of type IV with a type H2 hysteresis loop, indicating the existence of mesostructures. The synthesized samples were evaluated by photodegradation of tetracycline (TC) in visible light exposure compared to pure mesoporous ZnO nanoparticles (NPs) and commercial photocatalyst P-25. The photocatalytic efficiency mesoporous 3%Nd2O3/ZnO for degradation TC reached up to 100 % for 2 h compared to pure mesoporous ZnO and P-25 with 4 and 10 %, respectively. The mesoporous 3%Nd2O3/ZnO photocatalysts showed promoted photocatalytic performance, resulting in an improved photodegradation rate value up to 8.8 and 16.3 times that of compared to pure ZnO and P-25, which was explained by better photogenerated charge carriers separation as a result of heterojunction construction between Nd2O3 and ZnO interfaces. In addition, the 3%Nd2O3/ZnO photocatalysts showed sufficient stability for five repeated runs and created its potential utility for mitigation of organic pollutants in comparison to pure ZnO and commercial P-25.

Pluronic 31R1 surfactant and MCM-41 silica were used to fabricate mesoporous Ag2O/g-C3N4 heterostructures with improved surface areas. The fabricated mesoporous nanocomposite was used to photo oxidize ciprofloxacin. The TEM images of Ag2O/g-C3N4 indicated a uniform dispersion of spherical approximately 4-nm Ag2O nanoparticles on g-C3N4. The mesoporous 0.9% Ag2O@g-C3N4 heterostructure exhibited 100% efficiency in ciprofloxacin oxidation within 60 min when compared with the 25% efficiency in 120 min of pure mesoporous Ag2O and 10% efficiency in 120 min of pure g-C3N4. The highest ciprofloxacin oxidation efficiency achieved was 100%, which was four and ten times better than those of Ag2O and g-C3N4, respectively. This superior performance of the mesoporous Ag2O/g-C3N4 was attributed to the high dispersion of nano-sized mesoporous Ag2O particles on the g-C3N4 surface, narrow bandgap, and significantly high surface areas. The powerful interaction between Ag2O and g-C3N4 ensured robust durability of Ag2O/g-C3N4 heterostructures, which is evident in the fact that five recycling trials of the photocatalyst rendered a minimal loss of efficiency.

Background The CO2 photochemical conversion reaction has received attention under mild conditions. The CO2 photoreduction to CH3OH has become an approach of “one stone to kill two birds” since it provides the probability to complete the carbon circle and create invaluable products in a rotational economy. Method One-pot synthesis of porous ZnS@ZnO was developed with a large surface area of 1530 m2/g by Zn(NO3)2, Na2S and 2-methylimidazole as precursors. The obtained Pt/ZnS@ZnO heterostructure was evaluated for photoconversion of CO2 to CH3OH through visible light illumination. Significant findings The most photoactive 1%Pt/ZnS@ZnO showed a CH3OH formation of 1402 µmol g−1 after 9 h, which was enhanced 11.2- and 10.97- times larger than ZnO and ZnS@ZnO. The CH3OH formation rate over 1%Pt/ZnS@ZnO was promoted 12 times greater than ZnO and ZnS@ZnO heterostructure. The synthesized photocatalyst exhibited high stability and durability after five repeated cycles within 45 h. The superior CO2 reduction over Pt/ZnS@ZnO could be imputed to i) the construction of heterojunction between ZnS and ZnO, which enhanced the charge carriers-migration process and promoted the charge carriers lifetime; ii) the different energy levels led the high oxidative ability of the adsorbed OH‾ surface and hence facilitates the catch of photoinduced holes.

In the present contribution, the design and fabrication of Pt nanoparticle-decorated mesoporous ZnO–ZnS heterostructures were described and used effectively for photocatalytic CO2 conversion to yield CH3OH. TEM images of the mesoporous Pt/ZnS–ZnO heterostructure demonstrated spherical ZnO NPs ~20 nm, and Pt NPs ~3 nm were well dispersed on the porous ZnS–ZnO heterostructure. The formation of CH3OH over the Pt/ZnS–ZnO heterostructure was 78, 39 and 20 times larger than that bare ZnS, ZnO NPs and ZnS–ZnO, respectively. The optimal Pt/ZnO–ZnS heterostructure exhibited a high CH3OH formation rate of 81.1 μmolg-1h-1, which is about 44, 22 and 20 times larger than that of bare ZnS (1.86 μmolg-1h-1), ZnO (3.72 μmolg-1h-1), and ZnO–ZnS (4.15 μmolg-1h-1), respectively. The significantly enhanced reduction of CO2 was imputed to the synergistic effects of the ZnO–ZnS heterostructure and the incorporation of Pt NPs. The synthesized photocatalyst provides a new transfer route through which carriers can migrate to the outer surface as well as pore channels of the mesoporous ZnO–ZnS, therefore significantly minimizing the transfer distance for carriers, inhibiting photoinduced electron-hole recombination, and diminishing the mobility resistance, as determined using photoluminescence, photocurrent response, and electrochemical impedance spectra measurements.

In this contribution, a Z-scheme mesoporous BiVO4/g-C3N4 nanocomposite heterojunction with a considerable surface area and high crystallinity was synthesized by a simple soft and hard template-assisted approach. This material demonstrates superior visible light-driven photocatalysis for the photoreduction of Hg(II) ions. TEM and XRD results show that the mesoporous BiVO4 NPs, with a monoclinic phase and an ellipsoid-like shape, are highly dispersed onto the porous 2D surfaces of g-C3N4 nanosheets with a particle size of 5–10 nm. The obtained BiVO4/g-C3N4 nanocomposites with a p-n heterojunction show significantly enhanced Hg(II) photoreduction efficiency compared to the mesoporous BiVO4 NPs and pristine g-C3N4. Among all synthesized photocatalysts, the 1.2% BiVO4/g-C3N4 nanocomposite indicated the highest photoreduction of Hg(II) performance, reaching ~ 100% within 60 min; this result is 3.9 and 4.5 –fold larger than that of the BiVO4 NPs and pristine g-C3N4. The Hg(II) photoreduction rates highly increase to 208.90, 314.95, 411.23 and 418.68 μmol g−1min−1 for the mesoporous 0.4, 0.8, 1.2 and 1.6% BiVO4/g-C3N4 nanocomposites, respectively. The reduction rate of the mesoporous 1.2% BiVO4/g-C3N4 nanocomposite demonstrated a 5.2 and 3.8 times larger increase than that of the pristine g-C3N4 nanosheets and pure BiVO4 NPs. The superior Hg(II) photoreduction efficiency was ascribed to decreased carrier recombination and the improved utilization of visible light by constructing BiVO4/g-C3N4 nanocomposites with a p-n junction. Transient photocurrent measurement and photoluminescence spectra were employed to confirm the possible Hg(II) photoreduction mechanism over these BiVO4/g-C3N4 photocatalysts. This research provides an accessible route for the nanoengineered design of mesoporous BiVO4/g-C3N4 heterostructures that demonstrated unique photocatalytic performance.

Mesoporous TiO2 frameworks incorporated with diverse percentages of Cr2O3 nanoparticles (NPs) were achieved through the one-step sol-gel approach for photocatalytic H2 evolution under visible-light exposure. The obtained isotherms could be classified as type IV, indicating mesopore 2D-hexagonal symmetry. The H2 evolution rate over mesoporous Cr2O3/TiO2 photocatalyst was observably promoted employing glycerol as a sacrificial agent, providing a comparatively high H2 yield of 14300 μmolg−1. The highest photocatalytic efficiency was achieved with an optimal 4% Cr2O3/TiO2 photocatalyst, and the evolution rate was enhanced 1430-fold compared to pristine TiO2. The eminent photocatalytic performance of mesoporous Cr2O3/TiO2 was ascribable to different key factors such as the narrow bandgap, wide visible light photoresponse, Cr2O3 as photosensitizer, synergistic effect and high surface area. The recycle tests for five times over synthesized photocatalyst revealed excellent durability and stability without loss in H2 evolution. The photocatalytic mechanisms for H2 evolution over Cr2O3/TiO2 photocatalyst were proposed according to the photocurrent transient and photoluminescence measurements and photocatalytic H2 evolution results.

Herein, novel mesoporous CdS nanoparticle (NP)-incorporated porous g-C3N4 nanosheets with large surface areas and varying CdS NP percentages were constructed for the first time. The synergistic effect of mesoporous CdS NPs and porous g-C3N4 nanosheets indicated effective charge carrier separation and promoted CO2 photoreduction to form CH3OH upon illumination. The highest yield of CH3OH over 3% CdS-g-C3N4 heterostructures was determined to be approximately 1735 μmol g−1, which was 3.8- and 5.50 times greater than those of mesoporous CdS NPs and pristine g-C3N4 nanosheets, respectively. In addition, the mesoporous 3%CdS-g-C3N4 heterostructure showed an outstandingly enhanced CO2 photoreduction rate of 192.7 μmol g−1 h−1, which was estimated to be ~4.1 and 5.9- times better than CdS (47.1 μmol g−1 h−1) and pristine g-C3N4 (32.6 μmol g−1 h−1), respectively. The photoreduction performance was retained at approximately 94.7% after five cycles of illumination for 45 h. The remarkable synthesized mesoporous CdS-g-C3N4 heterostructure played an essential role, with its narrow bandgap and high surface area enabling improved photoinduced carrier separation and a widened range of light absorption. A plausible mechanism for CO2 photoreduction by the mesoporous CdS-g-C3N4 heterostructure was proposed and verified by photoelectrochemical and photoluminescence measurements.

Different organic pollutants have been remediated photo catalytically by applying perovskite photocatalysts. Atrazine (ATR) is a pesticide commonly detected as a pollutant in drinking, surface and ground water. Herein, FeYO3@rGO heterojunction was synthesized and applied for photooxidation decomposition of ATR. First, FeYO 3nanoparticles (NPs) were prepared via routine sol-gel. After that, FeYO3 NPs were successfully incorporated with different percentages (5, 10, 15 and 20 wt.%) of reduced graphene oxide (rGO) in the synthesis of novel FeYO3@rGO photocatalyst. Morphological, structural, surface, optoelectrical and optical characteristics of constructed materials were identified via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), adsorption/desorption isotherms, diffusive reflectance (DR) spectra, and photoluminescence response (PL). Furthermore, photocatalytic achievement of the constructed materials was evaluated via photooxidative degradation of ATR. Various investigations affirmed the usefulness of rGO incorporation on the advancement of formed photocatalysts. Actually, novel nanocomposite containing rGO (15 wt.%) possessed diminished bandgap energy, as well as magnified visible light absorption. Furthermore, such nanocomposite presented exceptional photocatalytic achievement when exposed to visible light as ATR was perfectly photooxidized over finite amount (1.6 g · L-1) from the optimized photocatalyst when illuminated for 30 min. The advanced photocatalytic performance of constructed heterojunctions could be accredited mainly to depressed recombination amid induced charges. The constructed FeYO3@rGO nanocomposite is labelled as efficient photocatalyst for remediation of herbicides from aquatic environments.

A surfactant F-127 was used to synthesize highly crystalline mesoporous ZnO nanoparticles (NPs) through sol gel process. The CdO NPs at four different percentages (1, 2, 3, and 4%) were deposited on the mesoporous ZnO matrix through an impregnation approach. The photocatalysts have been evaluated by the determination of rate of Hg(II) removal/reduction in presence formic acid as sacrificial holes compared to the commercial P-25 and undoped ZnO NPs under visible light exposure. The removal/reduction efficiency over mesoporous CdO/ZnO heterostructures was significantly promoted, and their photoreduction efficiency was achieved to 25, 65, 95 and 96% at 1, 2, 3 and 4% CdO/ZnO heterostructures, respectively compared to undoped ZnO (4%) and P-25 (6.9%). The maximum Hg(II) removal/reduction efficiency of 100% was achieved at optimized values over 3% CdO/ZnO heterostructure, which exhibited noticeably ~23.7 and 13.7 times higher than undoped ZnO NPs and P-25. Interestingly, the rate constant of 3% CdO/ZnO photocatalyst was significantly enhanced 46.9 and 27.7 times than that undoped ZnO NPs and P-25, respectively. The optimum 3%CdO/ZnO photocatalyst exhibited great potential for removal/reduction Hg(II) performance due to its small particle sizes, narrow bandgap, large surface area, and high crystallinity.

In this contribution, a novel mesoporous CuO/ZnO heterojunctions were fabricated and designed through a wet chemical process in the presence of F127 surfactant. TEM image of mesoporous CuO/ZnO heterojunction showed a homogeneous size distribution with uniform spherical with particles size ~20 nm. The surface area of pristine ZnO NPs was estimated to be 200 m2/g, which reduced to 175 m2/g at 4% CuO/ZnO heterojunction. The synthesized CuO/ZnO heterojunctions were exhibited to effectively reduction and removal of Mercury (Hg(II)) ions through visible light. The optimized mesoporous 3% ZnO/CuO heterojunction exhibited the highest photoreduction efficiency compared to commercial P-25 and pristine ZnO NPs. The photoreduction/removal efficiency of Hg(II) over 3%CuO/ZnO heterojunction was reached up to 100% within 60 min, which is ~14 and ~24 times higher than P-25 and pristine ZnO NPs, respectively. The rate constant of mesoporous 3% ZnO/CuO heterojunction is better 30 and 54 order magnitudes than that compared with P-25 and pristine ZnO NPs, respectively. This is explained by the mesoporous CuO/ZnO heterojunctions greatly promotes the utilization light rate owing to its characteristic architecture, increases the surface area and pore volumes, promoting mass diffusion and providing more active sites, enhances the photoinduced electrons transfer the as a result of the formation of p-n types CuO/ZnO heterojunctions. Nevertheless, the photocatalysts were readily reused and recovered for five cycles without significant loss of photoreduction efficiency.

In this study, mesoporous Bi2WO6/g-C3N4 heterojunctions were developed using soft and hard templates [triblock copolymer surfactant (F127) and mesoporous silica (MCM-41), respectively]. The performance of the developed heterojunctions was assessed through the photocatalytic reduction of mercuric cations under Vis light illumination, with HCOOH being adopted to provide sacrificial holes agent. Surface measurements demonstrated that the fabricated specimens acquired large specific surface areas when compared with the neat ingredient. Furthermore, a transmission electron microscopy (TEM) analysis of the developed heterojunctions showed the homogeneous distribution of the spherical Bi2WO6 nanoparticles (NPs) on the surface of g-C3N4 nanosheets. Meanwhile, an accelerated rate (700 μ·mol·g−1·h−1) of photocatalytic mercuric cation reduction with improved efficiency (approximately 100%), compared with those of the pure ingredients [rate of 55 μ·mol·g−1·h−1 and efficiency of 13% for g-C3N4 nanosheets; rate of 95 μ·mol·g−1·h−1 and efficiency of 20% for mesoporous Bi2WO6 NPs], was accomplished via testing of the Bi2WO6/g-C3N4 heterojunction comprising 4 wt% Bi2WO6 after 40 min of illumination. Evidently, the efficiency of the photocatalytic reduction of mercuric cations endorsing the Bi2WO6/g-C3N4 heterojunction comprising 4 wt% Bi2WO6 NPs is 7.7 and 5 times more when compared with those of the neat g-C3N4 nanosheets and mesoporous Bi2WO6 NPs, respectively. The improved performance of the fabricated heterojunctions in the photocatalytic reduction of mercuric cations could be ascribed to i) fast diffusion of the mercuric cations through the mesoporous texture to the active ensembles, ii) greater specific surface area, iii) limited bandgap magnitude, iv) homogenous dispersion of the Bi2WO6 NPs on the surface of the nanosheets, and v) finite particle dimension of the mesoporous Bi2WO6 NPs. The durability and stability of the Bi2WO6/g-C3N4 heterojunctions were confirmed via their recyclability, which was maintained for up to five runs without pronounced activity loss.

In this research, nanocomposites made of CuCr2O4-g-C3N4 accommodating distinct contents of CuCr2O4 (1-4 wt %) nanoparticles (NPs) were endorsed for hydrogen gas production after illumination by visible light in the presence of aqueous glycerol solution. The ultrasonication-mixture method was applied to assure the homogeneous distribution of CuCr2O4 NPs over synthesized mesoporous g-C3N4. Such nanocomposites possess suppressed recombination between the photoinduced charges. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy examinations affirmed the formation of CuCr2O4-g-C3N4 heterojunctions. The separation between the induced charges and the photocatalytic performance with the CuCr2O4 NP amount were investigated. The CuCr2O4-g-C3N4 heterojunction of 3 wt % CuCr2O4 content was documented as the optimal heterojunction. Upgraded hydrogen gas generation was attained over the optimal heterojunction with the extent of ten and thirty times as those registered for pure CuCr2O4 and g-C3N4 specimens, respectively, under illumination by visible light. The photocatalytic performance acquired by the diverse synthesized specimens was assessed not only by their effectiveness to absorb light in the visible region but also by their potential to separate the photoinduced charges.

Being a crucial matter for preserving clean and safe environment, remediation of sulfur-accommodating compounds as hazardous compounds from the polluted systems is immensely investigated by many scientists. One of the successful routes that displayed distinctive features towards desulfurization of thiophene, as an example of sulfur-containing compounds, is photocatalysis. In this investigation, Ag3VO4/rGO nanocomposites of various percentages of reduced graphene oxide (rGO) have been synthesized via dispersing Ag3VO4 nanoparticles prepared by the aid of the sol–gel method over rGO support. Supporting Ag3VO4 by 15 wt% rGO was district by narrowing the bandgap energy of Ag3VO4 to be 1.68 instead of 2.2 eV that participates strongly to the advancement of visible light absorption. Furthermore, photoluminescence evaluation affirmed that Ag3VO4/rGO-15 wt% nanocomposite acquired hindered recombination rate amid the photogenerated charges. The hindered recombination amid the photogenerated charges as well as the advanced visible light absorption play essential roles to establish efficient photoctalytic reaction. In this context, the synthesized Ag3VO4/rGO with the optimum composition accomplished complete (100%) photocatalytic performance against TP photooxidation when exposed to visible light for 2 h. From the economic point of view, the regenerated nanocomposite fetured excellent stability even after recycling up to five runs. Consequently, this investigation advances stable and applicable photocatalyst made of supported-metal oxide nanocomposite as an efficient and eco-friendly material to remediate TPs from the polluted systems.

In this probe, a convenient template was practiced to fabricate mesoporous PdO–TiO2 nanocomposites using a sol–gel routine. Photo-destruction of the herbicide imazapyr was adapted to figure out the photonic efficacies of the formulated nanocomposites. Furthermore, the appraised photonic efficacies were correlated with the photonic efficacies retained by commercial P25 Degussa as well as mesoporous titania. Progression of the tetragonal anatase phase of titania was entrenched via X-ray diffraction inquire. PdO–TiO2 nanocomposite accommodating 0.9% PdO possessed superlative photonic efficacy of 34.8% whereas, commercial P25 Degussa and mesoporous titania possessed photonic efficacies of 1.0 and 2.0% respectively revealing the superior photonic efficacy of the fabricated nanocomposites in comparison to other relevant photo-catalysts. In conclusion, PdO–titania nanocomposites acquiring enhanced charge carriers’ separation could be fabricated along with the collaborating action of both titania and PdO nanoparticles. Furthermore, the tremendous stability of the fabricated nanocomposites was ascertained via its implementation up to five cycles keeping its photo-catalytic performance without alteration. Hence, PdO nanoparticles could be formulated as fruitful promoters for the photo-catalytic aspects possessed by mesoporous titania.

Mesoporous CoAl2O4–TiO2 nanocomposites have been tested in this investigation to photo-destruct imazapyr herbicide waste. Numerous percentages of CoAl2O4 were utilized in the preparation of mesoporous CoAl2O4–TiO2 nanocomposites through the sol–gel method. It is terminated from Raman spectra and XRD data that practicing lower CoAl2O4 percentage brings about the progression of intensely crystalline anatase TiO2 phase, which is diminished by extending CoAl2O4 ratio. The surface texture investigation showed that specific surface areas of fabricated TiO2 NPs and 3.0% CoAl2O4–TiO2 nanocomposites are 180 and 160 m2 g−1, respectively, revealing that inclusion of CoAl2O4 has a negative effect on the surface area of TiO2 NPs. Photo-destruction of imazapyr herbicide has been selected to evaluate photocatalytic efficacy of the formulated CoAl2O4–TiO2 nanocomposites, and at the same time, it has been correlated with commercial P25 Degussa covered by irradiation of visible light. CoAl2O4–TiO2 nanocomposite, including 3.0 mass% CoAl2O4 has been established as the optimal composite to achieve the most favorable destruction. Indeed, the photo-destruction of imazapyr herbicide was 100% after 180 min of the reaction. Also, it was found that CoAl2O4–TiO2 nanocomposite incorporating 3.0 mass% of CoAl2O4 photodegraded the imazapyr herbicide 10.2 and 5.1 times faster correlated to P25 Degussa and mesoporous TiO2, respectively.

The challenge strategy for construction of the Z-scheme heterostructures including porous g-C3N4 based materials employing triblock copolymer and MCM-41 templates-assisted synthesis is to obtain stable photocatalysts with high charge-separation during photocatalysis application utilizing visible light. In this contribution, synthesis of mesoporous α-Fe2O3, CuO and CoFe2O4 nanoparticles (NPs) on porous g-C3N4 for promoted Hg(II) photoreduction efficiency have been evaluated compared with pristine g-C3N4. A Z-scheme system of mesoporous CuO, CoFe2O4 or Fe2O3-/g-C3N4 heterostructures provides an enhanced photocatalytic Hg(II) reduction, yielding a rate of 628.7, 472.2 and 424.1 μmolg−1h−1, respectively, which is ∼7.77, 5.84 and 5.24 times greater than that pristine g-C3N4 (80.85 μmolg−1h−1). The photocatalytic efficiency was improved up ∼100, 76.5, and 68.6% over mesoporous CuO, CoFe2O4 and Fe2O3-/g-C3N4, respectively, however, it was 12% over pristine g-C3N4 through 50 min illumination time. The enhanced photoreduction using Z-scheme CuO, CoFe2O4 and Fe2O3-/g-C3N4 heterostructures was attributed to its superb characteristics to expedite the photoreduction of Hg(II), involving: (i) 3D mesostructure and more suitable active sites which improves the Hg(II) adsorption, (ii) high surface area (188 m2 g-1) and narrow bandgap (1.93 eV) and (iii) the superior Z-scheme heterostructures characteristic efficiently enhances the electron-hole pairs separation. This research work creates new windows for mesoporous metal oxides and perovskites/g-C3N4 -based Z-scheme system for wastewater remediation, air purification and clean energy generation.

Fabrication of 3D mesoporous Ag2O-ZnO heterojunctions at varying Ag2O contents has been achieved through poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (Pluronic F-108) as the structure-directing agent for the first time. The mesoporous Ag2O-ZnO nanocomposites exhibited a mesoporous structure, which revealed a large pore volume and high surface area. The photocatalytic efficiency over mesoporous Ag2O-ZnO nanocomposites for tetracycline (TC) compared with that over commercial P-25 and pristine ZnO NPs through the visible light exposure was studied. Mesoporous 1.5% Ag2O-ZnO nanocomposites indicated the highest degradation efficiency of 100% of TC during 120 min of the visible light exposure compared with 5% and 10% for pristine ZnO NPs and commercial P-25, respectively. The TC degradation rate took place much rapidly over 1.5% Ag2O-ZnO nanocomposites (0.798 μmol L-1 min-1) as compared to either commercial P-25 (0.097 μmol L-1 min-1) or ZnO NPs (0.035 μmol L-1 min-1). The mesoporous 1.5% Ag2O-ZnO nanocomposite revealed the highest degradation rate among all synthesized samples, and it was 23 and 8 orders of magnitudes greater than those of pristine ZnO NPs and P-25, respectively. The photoluminescence and transient photocurrent intensity behaviors have been discussed to explore photocatalysis mechanisms. It is anticipated that the present work will contribute some suggestions for understanding other heterojunctions with outstanding behaviors.

In this work, we investigate nanostructured Cu2O-gC3N4 composites with diverse Cu2O addition (0.5–3.0 mol %) prepared by ultrasonication-mixture of mesoporous Cu2O and g-C3N4 prepared individually from soft and hard-template sol–gel, respectively. The efficiency of the Cu2O-gC3N4 nanocomposites depends on the Cu2O/gC3N4 ratio because it controls the heterojunctions development between them. The synergistic influence amid Cu2O and g-C3N4 in the nanostructured composites was demonstrated in the production of hydrogen under simulated light achieving a maximum efficiency at 2 mol % of Cu2O (17 and 38 times higher than on bare Cu2O and g-C3N4, respectively). Correlation between photoactivity and physicochemical characteristics of the Cu2O-g-C3N4 nanocomposites shows that the improvement in photoefficiency was related with the variances in the ability to absorb observable light and to separate the charge carriers associated to the different development of Cu2O/gC3N4 heterojunctions in the nanocomposites.

Mesoporous titania-silica (MTO) and mesoporous Pt-doped titania-silica (Pt@MTO) nanocomposites were synthesized by a facile synthesis procedure, and then, the nanocomposites were analyzed through a diverse range of techniques. XRD peaks and HRTEM images showed that the anatase phase of MTO and platinum was doped on the surface of the morphology of MTO as dots with an average size of 6 nm. Pt metallic nanoparticles were present in samples highly dispersed into mesoporous MTO. The varying portion of doping with Pt in the samples has a positive impact on the surface characteristics of nanocomposites. In addition, the increased ratio of Pt metallic nanoparticles in the samples reduced the band gap energies to 2.12 eV for 2.0% Pt@MTO and reduced the intensity of the emission spectrum by shifting the emission spectrum to a higher wavelength. The photocatalytic activity was measured by the degradation of ciprofloxacin (CIP) in the suspension. The 1.5% Pt@MTO photocatalyst fully photodegraded CIP after 60 min of irradiation. That performance exhibited excellent stability and recyclability.

In order to create a new design for an efficient photocatalyst, you need to decrease the obtained band gap and isolate the charge carriers photogenerated while setting up a new visible light methodology. The latter option could be accomplished via combination of catalyst in the metal oxide form over the surface of semiconductor. Hence, the current work aimed at synthesizing a new nanocomposite material from LaFeO3/g-C3N4 through the use of mesoporous silica as a template processing g-C3N4 higher surface area, which was subsequently decorated with LaFeO3. The LaFeO3 of variable content of 1∼4% was used to decorate our targeted basic material. The structure was confirmed by ordinary techniques, in addition to photocatalytic ability via splitting water reaction. g-C3N4 and LaFeO3 photocatalytic efficiencies were compared to the newly developed LaFeO3/g-C3N4 nanocomposites showing their outstanding activity. The optimum LaFeO3 content was confirmed as 3%, which gave higher photocatalytic efficiency against both g-C3N4 and LaFeO3 (34 and 21 times respectively). To enhance the catalytic system efficiency, a scavenger with a positive hole was added as glycerol. A maximum of five runs of higher efficient reuse was examined as required, as well as stable nanocomposite photocatalyst. The mesoporous structure, high surface area, and capacity of charge separation over the photocatalysis process were all investigated as main conditions which affect photocatalytic activity of LaFeO3/g-C3N4 nanocomposites.

Herein, triblock copolymer surfactant (F127) and mesoporous silica (MCM-41) as soft and hard templates were employed to synthesize of mesoporous CuO/g-C3N4 heterostructures with large surface areas for Hg(II) photoreduction in existence of formic acid as a holes sacrificial. TEM image for mesoporous CuO/g-C3N4 indicated that CuO NPs are homogeneously distributed with spherical shape in particle size ~5 nm onto the surface of g-C3N4. Mesoporous 2%CuO/g-C3N4 heterostructure was achieved a high Hg(II) photoreduction rate of 628.74 µmolg−1h−1 and high photoreduction efficiency of ~100% within 50 min compared with the pure either mesoporous CuO NPs (130.11 µmolg−1h−1, 21%) and g-C3N4 (88.54 µmolg−1h−1, 14%). The highest Hg(II) photoreduction rate achieved was 628.74 µmolg−1h−1, which is 4.83 and 7.1 magnitudes stronger than mesoporous CuO NPs and g-C3N4. The excellent photocatalytic performance of mesoporous CuO/g-C3N4 heterostructures for Hg(II) photoreduction is referred to highly dispersed mesoporous CuO NPs with small particle size onto g-C3N4, narrow bandgap, large surface area, a rapid transfer of Hg(II) ions and HCOOH to easily reach the active sites due to the facile penetration through the mesostructure, thus promoting the utilization of porous structure of CuO/g-C3N4 heterostructures for efficient diffusion of Hg(II) ions. The intense interaction between mesoporous CuO NPs and porous g-C3N4 confirms the durability of the CuO/g-C3N4 heterostructures during recyclability for five times.

This work explores the photoefficiency of mesoporous TiO2 photocatalysts modified with Ag0 and Ag2O in the photooxidation of imazapyr herbicide using visible light radiation. Ag/Ag2O–TiO2 photocatalysts with a variable Ag content (0.5–2.0 wt%) were synthesized through a sol-gel process. Their physicochemical properties were investigated by different techniques: N2 physisorption, XRD, HRTEM, FTIR, DRS UV–Vis, Raman, XPS, PL and photocurrent measurements. XRD and XPS showed the existence of both Ag2O and metallic Ag on TiO2 surfaces. UV–Vis spectra obtained for all Ag/Ag2O–TiO2 samples showed a shift in the absorption edge to the visible region and a decrease in the band gap energy (Eg) with respect to the pure TiO2. Photocatalysts with 1.5% and 2 wt % Ag loading showed total imazapyr destruction within 180 min upon visible light illumination. Both photocatalysts were found to degrade imazapyr herbicide 20.5 fold and 12.5 fold faster than the parent TiO2 and commercial Degussa P25, respectively. The high photoefficiency of the optimized Ag/Ag2O–TiO2 photocatalysts is explained by the combined effect of the presence of mesoporous anatase in the TiO2 matrix, creation of a p-n junction amongst the Ag2O nanoparticles and mesoporous TiO2 matrix, a low Eg and low recombination between photoinduced electrons and holes derived from the Ag2O–TiO2 p-n heterojunctions, and the presence of metallic Ag in the Ag2O particles, which promotes electron transfer in the p-n heterojunction.

In this study, mesoporous α-Fe2O3/g-C3N4 nanocomposites were constructed with diverse α-Fe2O3 contents for photocatalytic Hg(II) reduction under visible light by employing formic acid as a sacrificial donor and compared with either pure mesoporous α-Fe2O3 or g-C3N4. The α-Fe2O3 nanoparticles (NPs) were uniformly dispersed onto a layered g-C3N4 nanosheet with a particle size of 5–15 nm. The photocatalytic Hg(II) reduction efficiency of the α-Fe2O3/g-C3N4 nanocomposites was increased from 41.1% to 90% within 60 min with increasing α-Fe2O3 contents (1–6%). Interestingly, the photocatalytic Hg(II) reduction rate of the mesoporous 6%α-Fe2O3/g-C3N4 nanocomposite was 4.6 times and 6.8 times greater than that of both pure α-Fe2O3 NPs and g-C3N4 nanosheets, respectively. The key benefits of photocatalytic Hg(II) reduction over the use of mesoporous α-Fe2O3/g-C3N4 nanocomposites include the high crystallinity, narrow bandgap, large surface area, mesoporous structure, highly dispersed particles and small particle sizes of α-Fe2O3, and the use of a construction Z-scheme photocatalyst. The α-Fe2O3/g-C3N4 photocatalyst exhibited nearly stable photocatalytic Hg(II) reduction activity (for up to five respective recycles) without a significant reduction in photocatalytic efficiency. The obtained results may provide methods for the fabrication and design of new categories of Z-scheme photocatalysts for photocatalytic reduction and oxidation of toxic organic and inorganic pollutants under visible light.

The most herbicide used in agriculture in many regions is atrazine, which leads to many worries as reported by its toxicity. In this, we have synthesized BaTiO3 nanoparticles through a simple method, its absorption was converted from UV region to visible region via deposition of metallic copper using a photoassisted deposition way. The results of characterizations declared the act of Cu for enhancing the optoelectronic, optical, and structural properties of barium titanite photocatalyst. The bandgap of barium titanite photocatalyst can be controlled via controlling the weight percent of metallic copper. The outcomes declared 5 wt % of copper can reduce bandgap of BaTiO3 to 2.77 eV from 3.28 eV. The Cu@ BaTiO3 nanoparticles showed an exceptional atrazine photodegradation in the water at 1.6 gL–1 within 40 min with outstanding recyclability. The improvement of the photocatalytic activity of the prepared Cu@ BaTiO3 is specified to the local surface plasmon resonance(LSPR) of cupper-barium titanite photocatalyst. This diminishes the recombination rate of electron-hole and productively exceeds the undoped BaTiO3 photocatalyst.

CuO nanocompositions found many applications in chemistry and physics. However, its large band gap and charge carrier recombination when used as a photo catalyst hinder its effectiveness. In this paper we report a simple sol–gel method for the synthesis of mesoporous CuO nanosheets followed by the application of photo-assisted Pt incorporation to produce a uniformly Pt-decorated mesoporous CuO nanosheets. The nanosheet structure, crystallinity, morphology, and particle-size were confirmed employing XRD measurements, transition electron microscopy. The synthesized mesoporous Pt/CuO nanosheets showed high pore volumes of 0.350 cm3/g and a large surface area of 250 m2/g. The effectiveness of the photocatalyst was tested via application in the water splitting reaction under visible light and the use of glycerol as a positive hole scavenger. Pt/CuO yielded ~ 5400 µmol/g of H2, 7-times higher compared to pure mesoporous CuO. Higher efficiency is explained by narrower band gap, superior light harvesting capacity, and the efficient charge-carrier separation due to the use of glycerol. Photocurrent and photoluminescence were used to show the effect of Pt decoration on the photocatalytic efficiency of the material through the electron transfer from CuO to Pt atoms.

Mesoporous TiO2 nanoparticles were prepared by a sol-gel process employing the surfactant F127 as the template. α-Fe2O3 nanoparticles were impregnated onto mesoporous TiO2 surface at different contents (0.1–9 wt%) pursued by annealing at 400 °C. The TEM image of mesoporous Fe2O3/TiO2 nanocomposites exhibits the close contact of lattice fringes 0.35 nm of anatase (101) and the lattice spacing of 0.25 nm of the Fe2O3 (110). The synthesized α-Fe2O3/TiO2 nanocomposites were evaluated in the presence of glycerol as hole scavenger for H2 evolution under visible light illumination. Interestingly, the H2 evolution over 5%α-Fe2O3/TiO2 nanocomposites was amounted to be 11,500 μmol/g, which is higher 1150 times than that mesoporous TiO2. The initial rate of H2 evolution over mesoporous TiO2 is 1 μmolg−1h−1 which enhanced to 1000 μmolg−1h−1 at 5 wt% Fe2O3/TiO2 nanocomposite. The promoted photocatalytic performance was explained by a positive synergistic effect of α-Fe2O3/TiO2 nanocomposites with mesoporous structure, high separation of charge carriers and the enlargement of light harvest. The synthesized α-Fe2O3/TiO2 nanocomposites had an elegant photocatalytic activity and exhibited outstanding reusability and stability, which displayed a potential application in energy and environmental fields.

The incorporation of In2O3 nanoparticles on mesoporous La0.02Na0.98TaO3 photocatalysts is very interesting for promoting the H2 production under UV illumination in the presence of [10%] glycerol as a hole scavenger. It is demonstrated that an outstanding mesoporous In2O3/La0.02Na0.98TaO3 photocatalyst can be constructed by incorporating In2O3 nanoparticles (0-2 wt%) and mesoporous La0.02Na0.98TaO3 nanocomposites for highly promoting photocatalytic H2 evolution. The maximum yield of H2 ~ 2350 μmol g−1 was obtained over mesoporous 1%In2O3/La0.02Na0.98TaO3 nanocomposite. The mesoporous 1%In2O3/La0.02Na0.98TaO3 nanocomposite exhibited further enhancement H2 production, in which the rate of H2 evolution can be as high as 235 μmol g−1 h−1, 435 times higher than those of mesoporous La0.02Na0.98TaO3. The results showed that the 1%In2O3/La0.02Na0.98TaO3 photocatalyst possesses high stability and durability for H2 evolution by implying almost no photoactivity reduce after five cycles for 45 h continuous illumination. The measurement of photoluminescence spectroscopy, transient photocurrent spectra and UV- diffuse reflectance spectra for all synthesized samples exhibited that the promoted H2 production is mainly explained by its effective electron-hole separation and broaden photoresponse region due to its compositions and structures of the obtained heterostructures.

In this work, mesoporous Gd2O3-TiO2 nanocomposites synthetized by a sol–gel with vary Gd2O3 concentration were investigated for photo-destruction of imazapyr herbicide waste. Textural, structural and surface properties of the synthetized nanocomposites are verified by N2 physisorption, X-ray diffractometry, HRTEM and various spectroscopic techniques (FTIR, DRS UV–Vis, Raman, PL and XPS). HRTEM micrographs of the calcined Gd2O3-TiO2 revealed the existence of a mesoporous matrix consisting of homogeneously distributed TiO2 nanoparticles (NPs, 12 nm) which are decorated with Ga2O3 nanoparticles. It was found a reverse correlation between the amount of Gd2O3 concentration and the TiO2 nanoparticle size: the formation of smaller TiO2 nanoparticles was favored by the use of high Gd2O3 concentration. The photocatalytic efficiency of the synthetized Gd2O3-TiO2 nanocomposites was appraised in the photo-destruction of imazapyr herbicide below visible-light irradiation. The best herbicide destruction was achieved using 3%Gd2O3-TiO2 photocatalyst and degraded the imazapyr herbicide 20.5 and 8.2 times faster than a commercial P25 and non-promoted TiO2, respectively, indicating that modification of TiO2 with Gd2O3 led to a significant improvement of photocatalyst efficiency. This was explained as due to a lessening of the apparent optical bandgap and the formation of a large amount of surface defect states favoring the separation between electrons and holes. Besides its high efficiency, the 3%Gd2O3-TiO2 photocatalyst demonstrated to be recyclable and stable in the visible-light-driven photocatalytic destruction of imazapyr herbicide.