Sunlight Irradiation Research Articles

Molecular Engineering of Multivariate Porous Aromatic Frameworks for Recovery of Dispersed Uranium Resources

AbstractUranium plays an indispensable role in the sustainable development of nuclear industry, and the recovery of uranium from nuclear wastewater is one way to solve the shortage of uranium resources. However, the recovery of uranium resources from nuclear wastewater remains a challenge due to the interfere of coexisting ions. Herein, ratios of the adsorption group and photocatalytic enrichment group are well‐designed and controllably assembled into the porous aromatic frameworks (PAFs) using molecular engineering strategy to realize high uranium recovery efficiency and high resistance to interfering ions. The optimally coordinated multivariate PAF material PAF‐AN2T8‐AO exhibits bifunctions of adsorption and photocatalytic enrichment and thus, achieves high enrichment selectivity and high uranium recovery efficiency of 99% under simulated sunlight irradiation. Compared to PAFs with only adsorption group or photocatalytic group, the uranium recovery capacity of the optimized PAF is enhanced by 1.2 times and 2.3 times, respectively. Mechanistic studies reveal that the product of photocatalytic uranium on PAF‐AN2T8‐AO is air‐stabilized solid crystal metastudtite ((UO2)O2∙2H2O). This work provides a guiding method for designing adsorption‐photocatalytic bifunctional materials and proposes a more environmentally adaptable strategy for dispersed uranium resource recovery.

CuO/ZnO heterojunction nanofilm for effective photocatalytic disinfection

Pathogenic bacteria can spread rapidly from contaminated surfaces to human skin once humans touch such surfaces, resulting in contact infection and subsequent bacterial infectious diseases. In addition to the bacterial drug resistance induced by overuse of antibiotics, the commonly used antibiotic bacteria-killing strategy is unsuitable for surface sterilization of facilities. Herein, a heterojunction CuO/ZnO nanofilm was constructed on glass plates by calcination and atomic layer deposition. This film exhibited excellent photocatalytic antibacterial activity under visible light. The heterostructure between CuO and ZnO at the interface accelerated the separation of photogenerated electrons and holes, resulting in increased yield of reactive oxygen species, which effectively kill bacteria. After 5 min of simulated sunlight irradiation, the antibacterial efficiencies of CuO/ZnO against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were 99.68 ± 0.31 % and 96.49 ± 0.78 %, respectively. The photocatalytic antimicrobial nanofilm synthesized in this study can potentially be used for rapid and safe disinfection of contact surfaces in public facilities.

Comprehensive Understanding on the Aging Process and Mechanism of Microplastics in the Sediment-Water Interface: Untangling the Role of Photoaging and Biodegradation.

Microplastics (MPs) in coastal wetlands have been of great concern, but information on the aging behavior of MPs in the sediment-water interface is still lacking. In this study, the contribution of a typical abiotic (photoaging) and biotic (biodegradation) process and the underlying aging pathway of MPs with different degradabilities (including polypropylene, polyethylene terephthalate, and polylactic acid) were studied. With a quantified relative importance of photoaging (>55%) vs biodegradation, the crucial contribution of photoaging on MP aging was highlighted. This was likely attributed to more generation of reactive oxygen species (ROS) under sunlight irradiation conditions, containing O2•- and H2O2. By raising higher the level of malondialdehyde (0.5-3.5 times as high as that in the dark condition), these photochemically formed ROS caused oxidative stress and inhibited the selective attachment of plastic-degrading microbes on the MP surface, thereby weakening the effect of biodegradation. On this basis, the aging characteristics and potential pathway of different MPs were revealed. The functional group of nondegradable polypropylene tends to be broken by ROS first, while biodegradation (Arthrobacter oryzae and Bacillus sp.) played a relatively dominant role in biodegradable polylactic acid. This study provides a new sight for the understanding on the aging behaviors of MPs in the sediment-water interface.

Construction of Pillared-Layer Metal-Organic Frameworks as an All-Visible-Light Switchable Photocatalyst for Aqueous Cr(VI) Reduction.

Recently, two-dimensional metal-organic frameworks that are photoactive have shown great potential for efficiently converting solar energy into chemical energy. In this work, we successfully synthesized and designed two M2-MOFs ([Cu(L1)((CH3)2NH)]n (Cu-MOF) and [Zn(L1)(CH3)2NH)]n (Zn-MOF), H2L1 = 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid). Structural analysis suggests that the five-coordinated M(II) ion is surrounded by four oxygen ions from two ligands and one nitrogen atom from one dimethylamine molecule. The ligand spacer acts as a bridge between two SBUs and forms a 2D layer with rhomboid windows. These moieties are arranged in a staggered ABAB pattern, which likely aids in exfoliation. The UV-vis diffuse reflectance spectra (DRS) test shows that when the metal center in the MOF framework is replaced with Cu(II) ions, the light absorption range covers 200-1100 nm, which is much larger than the light absorption range of Zn-MOF. Moreover, the photoelectric current, electrochemical impedance spectra (EIS), and Mott-Schottky tests all indicate that Cu-MOF has better photoelectric properties. When applied to the photocatalytic reduction of Cr(VI), Cu-MOF and Zn-MOF can completely reduce Cr(VI) within 100 min under 450 nm LED light irradiation. Under sunlight irradiation, Cu-MOF can completely reduce Cr(VI) within 40 min, achieving the removal of Cr(VI) ions, which is much faster than the rate of Cr(VI) removal by Zn-MOF.

Bismuth molybdate nanoparticles modified graphene oxide: A novel nanocomposite for photocatalytic removal of organic dyes

Utilization of solar energy for the degradation of organic pollutants is a promising sustainable approach. Here in this research work, bismuth molybdate (Bi2MoO6) nanoparticles (NPs) modified graphene oxide sheets (Bi2MoO6@GO) were employed as efficient photocatalysts for the removal of organic dyes under illuminated sunlight. The synthesized nanocomposite was subjected to characterization via XRD, FTIR, Raman, SEM, EDX and UV–Vis spectroscopic analysis. The photocatalytic efficiency of fabricated nanocomposite (Bi2MoO6@GO) has been studied against organic pollutants including rhodamine B and methylene blue in aqueous solution under direct sunlight irradiation. Bi2MoO6 decorated graphene oxide nano-photocatalyst exhibited 91 % and 88 % degradation of methylene blue and rhodamine B within ∼ 70 min with apparent rate constant values of 0.0323 and 0.0246 min−1, respectively. The study showed that fabricated photocatalyst (Bi2MoO6@GO) possesses a comparatively low band gap, heterogeneous morphology and boosted active surface area which makes it an efficient photocatalyst for the effective remediation of organic pollutants.

Enhanced dielectric, magnetic, and photocatalytic properties of sol-gel synthesized Eu-Cr codoped BiFeO3 nanoparticles

A series of polycrystalline Eu-Cr co-doped BiFeO3 nanoparticles were synthesized using the sol–gel method. The obtained samples were characterized by employing the XRD, FTIR, FESEM, UV–vis, LCR meter, and SQUID techniques. XRD analysis confirmed rhombohedral phase formation for all samples, and the crystallite sizes decreased with higher Cr3+ doping concentrations. The stretching and bending vibrations of Fe-O bonds in FeO6 octahedra and the formation of perovskite nature were confirmed by the FTIR analysis. From microstructural studies, a decrease in crystallite size with increased doping concentration was observed, corroborating the XRD results. The magnetic studies revealed an enhanced magnetization, probably caused by the distorted cycloid spin structure of the codoped nanoparticles with size ≤62 nm. The lower value of the squareness ratio of the M-H loop indicated strong magnetostatic interaction between grains, which might have played a great role in the enhancement of the maximum magnetization of the doped samples. The dielectric constant and loss tangent were evaluated as a function of frequency at room temperature. The photocatalytic activities of all the samples were evaluated by measuring the degradation of RhB dye under sunlight irradiation. The highest photocatalytic degradation efficiency of 94% was achieved with the substitution of Cr3+ (3%) and Eu3+ (4%) ions in BiFeO3 nanoparticles.

Effective charge separation in CdS@PANI heterostructure for ultrafast visible light-driven photocatalytic reduction of uranium(VI)

The efficient treatment of uranium-containing wastewater provides guarantee for sustainable development of nuclear energy. In this work, a heterogeneous interface structure for photocatalytic reduction of U(VI) was proposed by in-situ decoration of cadmium sulfide (CdS) nanoparticles on polyaniline (PANI) nanorods. The strong coupling between CdS and PANI precisely modulated the interface electronic structure, which promoted the photogenerated charge separation. Multiple spectroscopic characterizations revealed that the interfacial charge polarization with the electrons gathering at the CdS surface and the holes gathering at the PANI, facilitating the performance of photocatalytic reduction of U(VI) under visible light irradiation. The optimal CdS@PANI-10 shows ultrafast U(VI) reduction with efficiency of over 96 % in 5 min. Moreover, the photocatalytic reduction of U(VI) over CdS@PANI-10 can also be activated by direct natural sunlight irradiation. The improvement of catalytic activity of CdS@PANI nanocomposite is due to faster charge separation and migration at the interface between CdS and PANI, as well as the formation of Type-II heterojunction, which was also beneficial for suppressing the CdS photocorrosion. This work introduces a potential strategy to design advanced photocatalysts with efficient electrons and holes separation toward practical application in uranyl ion conversion.

Improved naphthalene photodegradation rate of CN/Pt-P25 photocatalyst by effectively tuning Pt chemical states via H2 secondary annealing

Photocatalytic technology holds promising prospects for remediating naphthalene pollution in water bodies. In this work, the CN/Pt-P25 photocatalyst was successfully prepared via photodeposition combined with co-pyrolysis methods, and employed for naphthalene photodegradation under simulated sunlight. The chemical state of Pt was found to have a significant impact on the photocatalytic activity. H2 secondary annealing effectively tuned Pt chemical states, increasing the proportion of Pt0 species on the CN/Pt-P25 photocatalyst from 41.91 % to 62.24 %. The improved proportion of Pt0 species proportion led to a reduction in the bandgap, which induced changes in the band positions and notably enhancing the separation efficiency of photogenerated electron-hole pairs. Under simulated sunlight irradiation, (H2) CN/Pt-P25 photocatalyst achieved complete naphthalene photodegradation within 100 min. Thus, photocatalysts containing a high proportion of Pt0 species exhibited an improved performance in naphthalene photodegradation. These findings provide new insights into the application of photocatalytic technology for the remediation of PAHs.

Synthesis of Ag−Cu−MnO Triple‐Metal Composite And Evaluation of its Antimicrobial Activity and Dye Removal Efficacy

AbstractThe synthesis of triple metal oxide nanocomposites has revolutionized materials science due to their unique properties resulting from the interaction of multiple oxide components. This study aimed to synthesize mixed metal oxide nanocomposites using a co‐precipitation method with copper sulfate, silver nitrate, and potassium permanganate as precursor salts and sodium hydroxide as the precipitating agent. The resulting Ag−Cu−MnO triple metal composite was extensively characterized using X‐ray diffraction (XRD), scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (SEM‐EDS), and Fourier transform infrared (FT‐IR). The composite exhibited effective bactericidal efficacy against various bacterial strains, including Enterobacter bugandensis, Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa. Moreover, the composite demonstrated notable photocatalytic activity, degrading 87.26 % of 50 ppm Eosin Yellow within 140 minutes under sunlight irradiation, as monitored by a UV‐vis spectrophotometer. This study highlights the dual functionality of the synthesized composite as both a photocatalyst and an antibacterial agent. These findings underscore its potential for diverse applications in environmental remediation and healthcare, marking a significant advancement in materials science.

Enhanced photothermal conversion properties of graphene aerogel surface and its application in oil spill treatment

As an environmentally friendly material, graphene aerogel has been widely studied. The photothermal conversion performance is an important property of graphene aerogel. Graphene aerogels were prepared by hydrothermal reduction method. The factors affecting its surface photothermal conversion properties were explored and graphene aerogels with ideal photothermal conversion properties were obtained. In addition, COMSOL Multiphysics simulation was carried out to further analyze the intrinsic factors affecting the photothermal properties of the materials. The prepared materials were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectrometry (Raman) to obtain their physicochemical properties. UV–visible-near infrared spectrophotometer and microcomputer-controlled electronic universal testing machine were used to evaluate the light-absorbing capacity and mechanical properties of the materials. The obtained graphene aerogel can be rapidly heated up to higher than 110 °C in 8 s on its surface under simulated sunlight (1000 W·m−2) irradiation. When used for the treatment of oil spill at sea, the prepared graphene aerogel with good photothermal conversion ability can adsorb 105.61 times of its own weight of crude oil and the adsorption rate is as high as 10.56 g·g−1·min−1, which shows a broad application prospect.

Up-conversion luminescence and Bi SPR effect promoted Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst for efficient photocatalytic hydrogen production with simultaneous degradation of malachite green

Photocatalytic hydrogen production with simultaneous degradation of organic pollutants by using solar energy provide a promising strategy to solve the energy and environmental issue in the future. However, for onefold wide band-gap semiconductor, the poor photocatalytic efficiency limits its application on a large scale due to its easy recombination of photo-generated electron-hole pairs and low solar energy utilization. Herein, a novel Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst is prepared via photo-assisted isoelectric point method. In this composite photocatalyst, up-convention luminescence material, NaYF4:Er,Yb,Tm, can offer more ultraviolet light and visible light to intensify the activations of BiOBr and metal Bi nanoparticles, respectively. Furthermore, the formation of Z-scheme BiVO4(040)-BiOBr photocatalystic sytem, the spatial separation of the BiVO4(040) and BiVO4(110) facets and the presence of metal Bi surface plasmon resonance effect are contributed to the high-efficiency separation of the photo-generated electron-hole pairs. The experimental results show that as-prepared Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst exhibits advanced photocatalytic hydrogen production amount (192.0 μm) and excellent degradation ratio of malachite green (88.51 %) under simulated sunlight irradiation for 5.0 h. The apparent quantum yield of the Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst at 420 nm reaches a specific value of 5.8 %. In addition, Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst also remains a high stability in the photocatalytic hydrogen production with simultaneous degradation of malachite green within six reuse. At last, the possible reaction mechanism and degradation pathways of malachite green caused by Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst under simulated sunlight irradiation are put forward.

Photopatch testing: Clinical characteristics, test results, and final diagnoses from the North American Contact Dermatitis Group, 2009-2020.

Photoallergic contact dermatitis (PACD) is a delayed hypersensitivity reaction to allergens only in the presence of ultraviolet radiation in sunlight. Photopatch testing (PhotoPT) is necessary to confirm the diagnosis of PACD. There are few published studies of PhotoPT in North America. To summarise the results of patients photopatch tested by members of the North American Contact Dermatitis Group (NACDG), 2009-2020. Retrospective analysis of patient characteristics and PhotoPT results to 32 allergens on the NACDG Photopatch Test Series. Most of the 454 tested patients were female (70.3%), 21-60 years old (66.7%) and White (66.7%). There were a total of 119 positive photopatch tests. Sunscreen agents comprised 88.2% of those, with benzophenones responsible for over half of them. Final diagnoses included PACD in 17.2%, allergic contact dermatitis (ACD) in 44.5%, polymorphous light eruption (PMLE) in 18.9% and chronic actinic dermatitis (CAD) in 9.0% of patients. In 454 patients with suspected photosensitivity referred for photopatch testing in North America, approximately one-fifth had PACD. Sunscreen agents, especially benzophenones, were the most common photoallergens. Other common diagnoses included ACD, PMLE and CAD. Photopatch testing is an important tool for differentiating these conditions.

Rational design of nitrogen and carbon co-decorated mesoporous TiO2 composites for photocatalytic selective oxidation of alcohols

Photocatalytic organic synthesis has attracted much attention in recent years. Herein, a N and C co-decorated mesoporous TiO2 (mp-NCT) photocatalyst was synthesized for selective oxidation of alcohols. Notably, the as-prepared mp-NCT composites possess large specific surface areas and mesoporous structures, which could provide sufficient active sites and improve mass transfer. Furthermore, the co-doping of N and C species could not only extend the light absorption, but also tune the valence band of TiO2. Meanwhile, numerous oxygen vacancies and intra-band could be introduced, which helps to reduce the combination of the photogenerated carriers. As a result, the mp-NCT composites show excellent photocatalytic performance towards selective oxidation of benzyl alcohol and its derivatives to corresponding aldehydes under simulated sunlight irradiation. Mechanism studies revealed that the photogenerated electrons, holes and high dynamic equilibrium concentration of O2•- radicals were responsible for the efficient conversion of alcohols to aldehydes.

Development of a heterogeneous MOF-on-MOF photo-Fenton catalyst for highly efficient tetracycline degradation across a broad pH spectrum

The utilization of MOF-on-MOF heterojunction materials has demonstrated exceptional functional scalability; however, their application in the realm of photocatalytic degradation remains relatively limited. This study focuses on the synthesis of a MOF-on-MOF heterojunction involving the growth of Prussian blue (PB) onto the surface of ZIF-8, with ZIF-8 serving as a seed. The optimized MOF-on-MOF heterostructure catalyst, denoted as PB@ZIF-8, exhibited a degradation efficiency exceeding 98 % across the pH range of 4.0–10 in the Fenton system under sunlight irradiation. Notably, the reaction rate constant in the PB@ZIF-8/H2O2/Sun system was 0.029 min−1, which is 2.43 and 2.36 times higher than that of pure PB and ZIF-8. The superior performance of PB@ZIF-8 was attributed to the synergistic effect of PB and ZIF-8 in the MOF-on-MOF composite, which played a pivotal role in the tetracycline degradation process by enhancing light absorption and facilitating the separation of carriers. Furthermore, the PB@ZIF-8 catalyst exhibited exceptional stability, allowing for 5 cycles of recycling while consistently maintaining a degradation efficiency exceeding 97 %. This research not only expands the possibilities for architecting MOF-on-MOF structures but also contributes to the development of heterojunction materials for the removal of emerging pollutants from wastewater.

Exploring photocatalytic tetracycline removal performance under simulated sunlight irradiation: Milling time effect on metallic reduction of MnO/ZrO2 mixed oxide

In the present research, it is reported that ball milling technique can be applied to enhance the photocatalytic properties of MnO and ZrO2 metal oxide powders (MZOx) furthermore the fabricated photocatalyst can be used for the degradation of tetracycline (TTC). XRD analyses revealed that increasing the milling time resulted in the formation of a pure metallic Mn crystal phase, which boosted the antibiotic degradation rate. It was confirmed by SEM technique that the morphological structures of the particles were generally small and uniform. The band gap energy was calculated as 3.70 eV for the hybrid metal oxide. Additionally, the adsorptive and photoluminescence features were illuminated via DRS and PL analyses. The effect of milling time had a major impact on the photodegradation rate of TTC, and the 8 h milling sample (MZOx-8h) exhibited the highest catalytic degradation activity (79.4 %). Low photocatalytic activity was obtained at acidic pHs and increased at alkaline pHs. The presence of H2O2 sharply decreased photocatalytic process time (60 min) and 94.3 % of the TTC was degraded at 7.5 mM H2O2. The photocatalytic degradation process proceeded through superoxide radicals and was supported by holes. The stability of MZOx-8h almost remained constant (70.02 %) even after seven cycles. It was determined that the presence of oxalic acid positively affected the progress of TTC degradation reactions. Further, practical application areas were investigated and MZOx-8h doped on support materials was found to be suitable for such applications in proportion to the doping ratio. Finally, it was demonstrated that MZOx-8h exhibited remarkable performance in photocatalytic reactions of different types of organic pollutants. The synergistic nature of MnO and ZrO2 with the contribution of ball milling time effect resulted in high photocatalytic activity.

Construction of scheelite CaWO4 with natural diatomite for boosted photocatalytic degradation of tetracycline and doxycycline antibiotics under natural conditions

Fabrication of efficient and recyclable catalysts with natural supporting materials is still a challenge in the field of photocatalysis. In the present work, scheelite type calcium tungstate was successfully constructed with natural diatomite via in-situ co-precipitation method for effective photocatalytic degradation of tetracycline (TC) and doxycycline (DC) antibiotics. The as-synthesized photocatalysts were characterized by SEM-EDX, TEM, BET, XRD, XRF, XPS, FTIR, UV–vis DRS, PL and EIS techniques. The morphological and physiochemical analyses confirmed the successful hybridization of CaWO4 with natural diatomite. The optical, photoluminescence and electrochemical tests confirmed that the composite material displayed narrower band gap energy, lower recombination rate and facilitated separation of photogenerated carriers. After construction of CaWO4 with the diatomite structure, the TC and DC decomposition efficiencies were found 4.70 and 2.54 times higher than that of the pristine sample, respectively. Furthermore, the composite catalyst showed superior degradation performances (91.8 % for TC and 90.7 % for DC) in the presence of hydrogen peroxide as a Fenton-agent. The enhanced photocatalytic performance was assigned to the increased specific surface area and pore volume, decreased band gap energy, limited recombination rate of photoinduced carriers, decreased charge transfer resistance as well as the abundant of hydroxyl radicals. The degradation reaction was found to be mainly driven by photogenerated holes and superoxide radicals. The CWO@DT/Vis/Fenton catalytic system exhibited good performance at near-neutral pH, also the composite catalyst was sufficiently utilized in the presence of co-existing anions. Furthermore, the photocatalytic efficiency was also tested under natural sunlight irradiation and the TC degradation remained 71.4 % after four cycles, indicating the outstanding feature of the composite catalyst in outdoor process conditions. Under these circumstances, the present work demonstrated the utilization potential of natural diatomite for effective photocatalytic remediation of antibiotic molecules under natural sunlight irradiation.

Photocatalytic persulfate activation by silica microsphere-supported g-C3N4 for efficient carbamazepine degradation

A silica-loaded g-C3N4 composite photocatalyst (M-SiO2/g-C3N4) was prepared by grinding amorphous SiO2 microspheres (M − SiO2) with melamine and calcining the resulting grinding products. This composite was used for photocatalytic persulfate (PMS) activation to degrade carbamazepine (CBZ). The results showed that the degradation efficiencies of CBZ by M-SiO2/g-C3N4-2.5 (39.16 % of g-C3N4)-activated PMS were 78.92 % and 100 % after simulated sunlight irradiation for 60 and 120 min, respectively. These values were significantly greater than those of the system with pure g-C3N4 (29.15 % and 42.4 %). In particular, the degradation efficiency of CBZ with M-SiO2/g-C3N4-2.5 decreased by only 9.47 % after 4 cycles of recycling. In the catalytic process, h+, SO4•− and O2•− were the main reactive species contributing to CBZ degradation. Compared with g-C3N4, loading g-C3N4 on the surface of M − SiO2 resulted in a decrease in g-C3N4 lamellar stacking, which increased the number of active surface sites and improved the separation and migration of photogenerated carriers, improving the degradation performance.

Insight mechanism of magnetic activated catalyst derived from recycled steel residue for black liquor degradation

The present work deals with developing a method for revalorizing steel residues to create sunlight-active photocatalysts based on iron oxides. Commercial-grade steel leftovers are oxidized under different combinations of pH and temperature (50–90 °C and 3 ≥ pH ≤ 5) in a low energy-intensive setup. The material with the highest production efficiency (yield > 12%) and magnetic susceptibility (χm = 387 × 10−6 m3/kg) was further explored and modified by diffusion of M2+ (Zn and Co) ions within the structure of the oxide using a hydrothermal method to create ZnFe2O4, CoFe2O4 and combined Co–Zn ferrite. (Co–Zn)Fe2O4 displayed a bandgap of 2.02 eV and can be activated under sunlight irradiation. Electron microscopy studies show that (Co–Zn)Fe2O4 consists of particles with diameters between 400 and 700 nm, homogeneous size, even distribution, and good dispersibility. Application of the developed materials in the sunlight catalysis of black liquors from cellulose extraction resulted in a reduction of the Chemical Oxygen Demand (− 15% on average) and an enhancement in biodegradability (> 0.57 BOD/COD) after 180 min of reaction. Since the presented process employs direct solar light, it opens the possibility to large-scale water treatment and chemical upgrading applications.

Novel S-scheme β-Cu2V2O7/Ni/Pg-C3N4 heterojunction photocatalyst for sunlight-induced degradation of RhB

A novel S-scheme β-Cu2V2O7/Ni/Pg-C3N4 nanocomposite photocatalyst has been advantageously established by propelling β-Cu2V2O7 nanoparticles (NPs) on the top layer of porous graphitic carbon nitride (Pg-C3N4) nanosheets (NSs) using a facile co-precipitation approach. Implementing photoelectrochemical and physicochemical techniques, the crystallinity, purity, optical quality, morphology, chemical composition, and charge separation efficiency of the produced samples were examined. The outcomes indicate that metallic Ni and β-Cu2V2O7 NPs were perfectly encapsulated onto the Pg-C3N4 NSs and well-matched band structures between both semiconductors facilitate the creation of an S-scheme charge transfer path. The fabricated pristine and β-Cu2V2O7/Ni/Pg-C3N4 composite samples were utilized as a catalyst for the removal of rhodamine B (RhB) dye under sunlight irradiation. The β-Cu2V2O7/Ni/Pg-C3N4 nanocomposite exhibits exceptional activity within 60 min of radiation exposure (RhB- 98.56%), whereas β-Cu2V2O7 and Pg-C3N4 show reduced activity (RhB-34.4% and 45.68%). The favourable impact of S-scheme nanocomposite establishment boosted photocatalytic behavior using the intrinsic electric field among Pg-C3N4 NSs and β-Cu2V2O7 and surface plasmon resonance (SPR) effect of metallic Nickel (Ni) NPs for delivering e− and h+ pairs and prolonging the life of charge carriers. According to radical scavenging experiments •O2− is the primary reactive species followed by •OH radicals. The produced nanocomposite has the potential to be employed in large-scale photocatalytic water treatment, as evidenced by the photocatalyst's excellent efficiency and reusability after five consecutive experiments.

Cu-Fe bimetallic MOFs with long lifetime separated-state charge for enhancing selectivity for CO2 photoreduction to CH4

Improving the CO2 to CH4 conversion efficiency of Cu metal-organic frameworks (Cu-MOFs) catalysts is important for promoting carbon capture and utilization. In this work, a series of novel Cu-Fe bimetallic MOFs photocatalysts (Cu-BTB-Fe with 0.5 wt%, 1.0 wt%, 2.0 wt%, and 4.0 wt% of Fe; H3BTB = 1,3,5-tris(4-carboxyphenyl) benzene) were synthesized by a bimetallic site (Cu and Fe) design strategy in order to improve the electron-hole separation efficiency and CO2 adsorption activation. Findings indicated that the as-synthesized Cu-BTB-2 wt% Fe catalyst exhibited excellent catalytic performance for the conversion of CO2 to CH4 and CO under simulated sunlight irradiation, providing a yield of 32.20 μmol∙g−1∙h−1 and a selectivity of 69.24 % for CO2 to CH4 conversion as well as a yield of 14.29 μmol∙g−1∙h−1 for CO2 to CO conversion without liquid phase products. This is because the Cu-Fe bimetallic sites can continuously supply photoinduced electrons with long separated-state decay lifetime to efficiently activate CO2. Specifically, the Cu-BTB-Fe catalysts provided a high proportion of effective photoinduced electrons with long decay lifetime for the CO* hydrogenation process through a unique electron transfer mechanism, while the strong affinity between CO2 and [Cu2(COO)4]-Fe active units enabled high CO2 adsorption activation and rapid CO2 reduction. The present approach, hopefully, would help to establish feasible pathway for the development of novel highly selective Cu-based MOFs photocatalysts for CO2 photocatalytic reduction yielding CH4.