Lasers Research Articles

Simultaneous photocatalytic degradation of remdesivir, favipiravir, and diclofenac from aqueous solutions using a quaternary plasmonic Ag/Ag-SG-TiO2-rGO photocatalyst: Synthesis, characterization, optimization, and toxicity assessment

This study presents a novel quaternary plasmonic photocatalyst, Ag/Ag-Sol-Gel(SG)-TiO2-rGO, designed for efficient removal of remdesivir (RDV), favipiravir (FAV), and diclofenac (DCF) as COVID-19 antiviral drugs from water samples. Various characterization techniques were employed to analyze the Ag/Ag-SG-TiO2-rGO nanocomposites, which were synthesized with different Ag to SG-TiO2-molar ratios. The photocatalyst, containing 30 % Ag plasmonic within its framework, exhibited the highest pollutant removal under visible light. This efficiency is attributed to the surface plasmon resonance (SPR) generated by metallic Ag nanoparticles and the optimal energy alignment between the TiO2 conduction band and the rGO work function. Trapping experiments were used to identify the most active species. It was confirmed that O2− and OH were the main active species in the photocatalytic process. The degradation kinetics, following a pseudo-first-order model, was assessed using an optimized LC-MS/MS. An optimization of the photodegradation process was done using a central composite design, as well as a study of the effects of prolonged irradiation. This resulted in the total elimination of the target compounds at a dosage of 0.087 g, irradiation time of 80 min, and pH value of 8. The photodegradation efficiency of sewage treatment plant effluent and tap water was reduced by matrix components, particularly in highly contaminated samples. An additional confirmatory MTT assay revealed a very low viability difference for mouse fibroblast cells, L929, in untreated, treated (97 %) and control samples. This study sheds light on the photodegradation of anti-COVID-19 drugs and offers insights into their remediation in aquatic environments.

Construction of g-C3N4-based donor-acceptor conjugated copolymer for photocatalytic selective oxidation of biomass-derived 5-hydroxymethylfurfural under visible light

Donor-acceptor structure porous nanosheets CNSA-x (x denotes the amount of salicylic acid) were prepared by co-thermal condensation polymerization of aromatic compound salicylic acid (SA) and prepolymer melamine. A variety of characterization methods have been used to thoroughly analyze the morphology, structure, optical and electrical features of the synthesized catalysts. It turned out that the introduction of SA promotes the formation of pore structure and an enhanced specific surface area, which resulted in more reactive sites. Moreover, the introduction of SA improves light absorption capacity and effectively adjusts the valence band position. Meanwhile, it also extends the delocalization system, thereby promoting the migration and separation of photogenerated electron-hole pairs. The catalyst exhibited high performance and stability in the photocatalytic oxidation of 5-hydroxymethylfurfural (HMF) under the synergies of these advantages. Additionally, the elucidation of active reaction species and proposed reaction mechanism enriched the understanding of the catalytic process.

Iron, cobalt embedded nitrogen-doped carbon derived from conjugated macrocyclic polymers as electrocatalysts for oxygen reduction reaction

The synthesis of earth-abundant metal-based electrocatalysts for deploying electrochemical energy devices has become an area of considerable interest. Herein, we have illustrated a facile Friedel-Crafts reaction for designing a metalloporphyrin polymer followed by its calcination to synthesize cauliflower-like nitrogen-doped iron-cobalt bimetallic electrocatalyst (FeCoTpp-900-2) and its satisfactory performance toward reducing oxygen. The bimetallic FeCoTpp-900-2 catalyst exhibits a half-wave potential (E1/2) of 0.84 V (vs. reversible hydrogen electrode (RHE)) and an onset potential (Eonset) of 0.95 V (vs. RHE). The notable electrocatalytic activity for oxygen reduction reaction (ORR) of FeCoTpp-900-2 is attributed to the presence of ORR active nitrogen species along with the Fe-Nx/Co-Nx sites. In addition, FeCoTpp-900-2 possesses an appreciable amount of mesopores responsible for the ORR behavior. Notably, the zinc-air battery consisting of FeCoTpp-900-2 as the catalyst for the air cathode presents a maximal power density of 127.53 mW cm−2 and robust durability for 24 hours (h). Therefore, this work can contribute to the facile synthesis of bimetallic electrocatalysts with non-noble metals to explore their applications in ORR.

Enhanced Antibiotic Degradation Using rGO Composites under Visible Light Photocatalysis

A robust reduced graphene oxide (rGO), polyaniline (PANI) with calcium (Ca) and magnesium (Mg) bimetallic nanocomposite was successfully prepared using an in-situ chemical facial reducing method and named rGO@PANI-Ca:Mg. Various spectroscopic techniques, including XRD, SEM, TEM, XPS, and supplementary methods, were utilized to characterize the catalyst phase, microstructure, and optical attributes. The composite's photocatalytic efficiency was assessed by degrading antibiotics such as ciprofloxacin (CP) and tetracycline (TC) using calcium peroxide (CaO2) under visible light irradiation. The rGO@PANI-Ca:Mg composite demonstrates superior degradation efficiency for CP, 45%, and for TC, 70%, achieving a correlation coefficient R² of 0.94 and 0.991 respectively. This performance surpasses that of pristine GO, rGO, and rGO@PANI. The heightened photocatalytic activity is ascribed to forming a heterojunction, effectively mitigating electron-hole pair recombination. The incorporation of CaO2 promotes the generation of additional active reactive oxygen species (ROS), particularly OH·, ·O2−, e-, h+, as verified by radical scavenging experiments, indicating an enhancement in the degradation and a potential mechanism is also suggested. The degradation rate of TC, CP, and real wastewater (RW) is about 71%, 45 %, and 40.98 %, respectively. The composite demonstrates stability and reusability for up to three catalytic cycles. Our experiments also showed that when bacteria were treated with a 2 mg catalyst, the minimum inhibitory concentration (MIC) was determined to be at a 10-3 dilution. This MIC value represents the lowest concentration at which the catalyst effectively inhibited bacterial growth, as evidenced by clear inhibition zones.

CO2(OH)2CO3 and Fe doped Co2(OH)2CO3 prepared as efficient and stable catalysts for activation of PMS: Two systems comparison and key role of high-valent metal-oxo species in mechanism revealing

High-valent metal-oxo species [M(IV) = O] exhibited high selectivity and chemical efficiency in advanced oxidation processes for removing organic pollutants, making their manipulation essential in catalytic systems. However, the low and unsustainable efficiency of generating M(IV) = O posed significant challenges. In this research, Co2(OH)2CO3 were successfully prepared via a one-pot hydrothermal method to efficiently activate peroxymonosulfate (PMS) with high-valent cobalt-oxo species [Co (IV) = O] as the primary active oxidation species. Building upon this foundation, COC was modified through variations in metal types and elemental ratios, in which magnetically enriched FexCo2-x(OH)2CO3 was synthesized by gradient Fe doping with higher catalytic efficiency and stability. The insertion of Fe resulted in the lengthening of the Co-O bond and improved the valence distribution of cobalt on the COC surface. Besides, it enabled part of the electrons to be transferred from the Fe active center to the Co active center, breaking the limitation of the traditional two-electron transfer and realizing the stable generation of more high-valent metals. Both reaction systems achieved efficient degradation of sulfadimethoxine (SDM) within 30 min and were able to completely degrade SDM within 30 min even after three cycles. FexCo2-x(OH)2CO3 maintained excellent catalytic performance even after 30 days of exposure to air. In both systems, high-valence metals played a dominant role, while the contributions of hydroxyl radicals and sulfate radicals were negligible. Overall, the two groups of developed catalysts both showed remarkable stability and pollutant removal performance in anions, humic acid, Different antibiotics and real water systems, which provided a new perspective on antibiotic removal.

Application of catalyst Cu-t-ZrO2 based on the electronic metal-support interaction in electrocatalytic nitrate reduction

A novel Cu-t-ZrO2 catalyst with enhanced electronic metal-support interaction (EMSI) is designed for efficient electrocatalytic conversion of nitrate (NO3−) to ammonia (NH3), achieving a remarkable Faradaic efficiency and yield rate of 97.54% and 33.64 mg h−1 mgcat−1, respectively. Electrons are more likely to be transferred from Cu to t-ZrO2 at the electron-rich interface due to the lower work function, which promotes the formation of highly active Cu species and facilitates NO3− adsorption, ensuring selective conversion into NH3.

In-situ realtime study of zinc selenide nanoparticles sustained by polypyrrole in alkaline water oxidation

Interest in metal electrodeposition for synthesizing customized nanomaterials has resurged, particularly for applications such as sensors and fuel cells. The present study involved the synthesis of ZnSe nanoparticles (via hydrothermal method) while polypyrrole and novel composite Ppy@ZnSePpy@Ppy (via sequential electrodeposition technique) on a glassy carbon (GC) electrode and their physiochemical, electrochemical, and operando spectro-electrochemical characterizations towards oxygen evolution reaction (OER). Results indicated that ZnSe nanoparticles are well embedded within the Ppy layers and during OER the composite electrocatalyst approached 398 mV at 10 mA cm−2 and exhibited Tafel value (b ∼ 75 mV dec−1) with ECSA (0.03) which shows better results than other two. In addition, the operando spectro-electrochemical spectra of the composite revealed the significant generation of active intermediate oxygen species of selenium and Zn2+. The important feature of the current work is the disclosure of Se's questionable role and species involved in OER found to be Se4+.

Development of optimal indoor air disinfection and ventilation protocols for airborne infectious diseases.

Since the COVID-19 pandemic, there has been persistent emphasis on the importance of indoor air disinfection and ventilation in isolation units in the hospital environment. Nevertheless, no optimal and concrete disinfection protocol has been proposed to inactivate the viruses as quickly as possible. In this study, we experimentally evaluated various ventilation and disinfection protocols based on the combination of negative-pressure ventilation, ultraviolet (UV) light illumination, and Hypochlorous acid (HOCl) spray against three active virus species in a 3.5 cubic meters isolation unit. This small-size unit has gained attention during the pandemic due to the high demand for compact mobile laboratory systems capable of rapid disease diagnosis. In accordance with the WHO laboratory biosafety guidance, which states that all enclosed units where diagnostic work is conducted must ensure proper ventilation and disinfection activities, we aim to propose virus removal protocols for units compact enough to be installed within a van or deployed outdoor. The results confirmed the superiority (in terms of virus removal rate and time required) of the virus removal methods in the order of UV light, ventilation, and HOCl spray. Ultimately, we propose two optimal protocols: (i) UV light alone for three minutes, and (ii) UV light with ventilation for three minutes, followed by one-minute ventilation only. The time span of three minutes in the latter protocol is based on the clinical practice such that the medical staffs have a sufficient time to process the samples taken in transition to next patient to care.

Mitigating environmental assisted cracking in heterogeneous welds by laser peening without coating

In this work Laser Peening without Coating (LPwC) was applied underwater on heterogeneous weld joint made of P265GH and X6CrNiTi18-10 steel tubes to prevent Environmental Assisted Cracking on the weld/P265GH steel fusion boundary. Special laser head was designed to precisely deliver 200 mJ green laser beam on the centrally located weld interface on the inner surface of a pipe 76 mm wide and 420 mm long. Residual stress analysis revealed that the LPwC treatment led to generation of compressive residual stresses in the critical fusion boundary area with the magnitude of −168 MPa despite the absence of a protective layer in the peening process. The depth of compressive stresses reached up to 0.8 mm. Plastic deformation induced by LPwC led to grain refinement in the microstructure and improved hardness by 16 %. Samples sectioned from the treated pipe were subjected to accelerated corrosion-mechanical testing which showed more than 2.5x increase in cycles to failure after LPwC. Fractography analysis showed shorter length and decreased number of corrosion cracks after LPwC as well as formation of protective oxide layer on top of the treated surface. 3-point bend testing further showed more than 8x increase in corrosion fatigue life.

Improving photoelectric characteristics of GaN-based green laser diodes by inserting electron blocking layer with gradient Al composition

This paper proposes four new gradient composition electron blocking layer (EBL) structures to enhance the photoelectric performance of GaN-based green laser diodes (LDs). The optical and electrical properties of new structure LDs are theoretically analyzed by LASTIP. It is observed that the implementation of a gradient composition EBL structure increases the effective barrier height for electrons, thereby better inhibiting the electron current overflow from the active region. In addition, the optical field leakage is effectively suppressed, lower threshold current and higher output power are obtained. The four different new structures have obvious differences in the improvement of the hole current injection and slope efficiency of multiple quantum well (MQW) LDs, and the underlying reasons for these phenomena are explored. Simulation results indicate that adopting a gradually descending Al component EBL structure yields optimal improvements in the photoelectric performance of LDs.

Sulfur-doped CuCo2O4 as a PMS activator: The synergy of oxygen defects and strong Lewis acid sites in boosting the elimination of ciprofloxacin

Herein, the synthesis of sulfur-modified CuCo2O4 (S-CuCo2O4) nanoparticles as a heterogeneous catalyst for peroxymonosulfate (PMS) activation was reported. The S-CuCo2O4 maintained the spinel structure and exhibited rich oxygen vacancies. Also, the presence of S atoms enlarged the specific surface area and created strong Lewis acid sites that both enhanced the adsorption ability toward PMS and CIP. Compared to the corresponding S-doped single oxides and CuCo2O4, the S-CuCo2O4 with the designed molar ratio of S and metal ions to be 10%, i.e., CCS-10, significantly improved the catalytic activity, indicating the synergism between Cu-O-Co bonds, the oxygen vacancies, and the Lewis acid sites. Under the optimal conditions of 0.1g.L-1 CCS-10 dosage, 0.2g.L-1 PMS, and natural pH, the CCS-10/PMS system could remove approximately 87% of CIP and 70% of TOC within 20min at a four-time higher rate than that of the pristine catalyst. This system showed the highest performance in the pH range from weak acidic to weak basic (pH 5.5 - pH 8.5). CCS10/PMS also displayed considerable efficiency in degrading various pollutants belonging to different categories (methylene blue (MB), carbamazepine (CBZ), bisphenol A (BPA), and sulfamethoxazole (SMX)). SO4•–, •OH, O2•–, and 1O2 active species were found to be responsible for CIP elimination. Finally, the PMS residual concentration was recorded to be 0.01g.L-1 after the reaction. Overall, this study could contribute a possible strategy to enhance the heterogeneous catalysts for the removal of organic pollutants.

Novel environmentally-friendly 0D/3D TiO2@FeMoO4 binary composite with boosted photocatalytic performance: Structural analysis and Z-scheme interpretations

For efficient pollutant degradation under any extreme circumstances, TiO2-based photocatalyst being accessible and inexpensive will be a desirable engineering source satisfying excellent photocatalytic performance in an eco-friendly manner. Here, we report the unfolded way of designing the novel concept of Z-scheme heterojunction consisting of TiO2 and FeMoO4 via thermal techniques in which hydrothermal treatment was coupled sequentially by the calcination step. The well-aligned band structure of the developed composite, possessing numerous active sites, enhanced the separation of the generated charge carriers which in turn boosted the photocatalytic efficiency. The prepared photocatalysts were thoroughly investigated via different techniques like XRD, FTIR, XPS, SEM, TEM-EDS, Pl, UV-Vis diffuse reflectance, and Uv-Vis spectroscopy. The TiO2-8 wt.% FeMoO4 (TF 8%) photocatalyst displayed better photocatalytic performance for removing Basic Fuchsin dye (BF) in 20min than other counterparts under visible light irradiation. Furthermore, the probable photocatalytic mechanism was evidenced by XPS results and the trapping experiments. Trapping experiments revealed that •O2− and •OH radicals were the primary active species. The synthesized TF 8% photocatalyst has revealed outstanding durability after five successive recycles without change in the structural features which was confirmed by XRD analysis. This work could provide new perspectives into various environmental applications by utilizing highly efficient materials that have been strategically constructed.

Synergistic adsorption&photo-Fenton degradation of meloxicam and tetracycline by hollow nanoflower-like S-scheme FeWO4/ZnIn2S4 heterojunction: Mechanism, toxicity assessment, and potential applications

The rational construction of materials with dual rapid adsorption&photo-Fenton oxidative degradation functions holds great significance in the field of removing difficult-to-degrade organics. A late-model S-scheme heterojunction photocatalyst FeWO4/ZnIn2S4 was prepared by solvothermal method in this paper. The FeWO4 nanoparticles were distributed on the surface of the hollow nanoflowers assembled by ZnIn2S4, forming heterojunction structures. Representative drug residues, tetracycline (TC) and meloxicam (MLX), were selected as targets to systematically explore the removal properties of FeWO4/ZnIn2S4. This photocatalyst exhibited suitable adsorption ability, excellent photocatalytic performance, and good photo-Fenton ability for both targets. The removal efficiency of tetracycline and meloxicam by 20-FW/ZIS reached 92.9 % and 98.7 %, respectively, through a combination of adsorption&photo-Fenton degradation, with these remarkable properties being maintained after four consecutive cycles. Based on the detection of active species and the analysis of degradation intermediates, an adsorption&photo-Fenton removal mechanism and possible degradation pathway were proposed. Escherichia coli (E. coli) inhibition experiments, combined with Toxicity Estimation Software Tool (T.E.S.T.) simulated toxicity analysis, showed that the toxicity of TC and MLX decreased significantly following the photocatalytic reaction. In brief, the newly developed multifunctional photocatalyst 20-FW/ZIS, as prepared in this paper, demonstrates great potential for effectively treating organic matter in wastewater, with promising applications for practical use.

Lattice distortion effects in high-entropy oxides: Boosting PMS activation for effective and durable pollutant degradation

Advanced Oxidation Processes (AOPs) are highly effective for pollutant removal, but achieving an optimal combination of high reactivity, corrosion resistance, and long-term stability remains challenging. In this study, we present the synthesis of a distinctive hollow prismatic high-entropy oxide, (Co0.2Ni0.2Mn0.2Cu0.2Zn0.2)3O4, derived from complex coordination polymers. This high-entropy oxide exhibits significant lattice distortion effects compared to conventional (Co1/3Ni1/3Mn1/3)3O4 and Co3O4. These distortions reduce the metal-O bond length, which enhances cyclic stability during peroxymonosulfate (PMS) activation for pollutant degradation. Additionally, the improved interaction between the catalyst and PMS enhances the generation of reactive oxygen species (ROS), leading to superior catalytic degradation activity. Electron paramagnetic resonance (EPR) and other analytical techniques identify ·OH, 1O2, O2−· as the primary active species in the (Co0.2Ni0.2Mn0.2Cu0.2Zn0.2)3O4/PMS system. A degradation mechanism for tetracycline (TC) is also proposed. This study introduces an innovative approach to water treatment by employing high-entropy oxides to activate PMS, demonstrating substantial potential for practical applications.

The interstitial Ru dopant induces abundant Ni(Fe)[sbnd]Ru cooperative sites to promote ampere-level current density for overall water splitting

Directionally induced interstitial Ru dopant rather than ordinary substitutional doping is a challenge. Furthermore, DFT calculations revealed that compared with the substituted Ru dopants, the interstitial Ru dopants induce abundant Ni(Fe)Ru cooperative sites, greatly expediting the reaction kinetics for HER and OER. Inspired by these, the interstitial Ru-doped NiFeP/NF electrode is constructed by the ’quenching doped Ru-phosphorization’ strategy. Relevant physical characterizations confirmed that interstitial Ru dopants promote electron reset in the Ni(Fe)Ru synergistic sites, effectively avoiding metal atom dissolution and encouraging more Ni (Fe)OOH active species. As expected, the Ru-NiFeP/NF||Ru-NiFeP/NF electrolyzer only need as low as 1.54 V to yield a current density of 1 A cm−2. In summary, this work innovatively constructs the phosphide electrode with ampere-level current density from the perspective of regulating the doping position of Ru. This provides a new design idea for optimizing the Ru doping strategy.

Novel biomass carbon dots/chitosan hydrogel-modified TiO2: An effective reduction of Cr(VI) in various wastewater under sunlight

Hexavalent chromium (Cr(VI)) poses a serious threat to the environment and human health owing to its inherent toxicity. Photocatalysis technology has garnered widespread attention owing to its efficiency and environmental friendliness. However, existing photocatalysts are constrained by light conditions, low reduction rates, and lack of studies in real wastewater. In this study, biomass carbon dots (P-CDs) were synthesized from peanut shell powder, then combined with chitosan (CS) and TiO2 to create a novel photocatalyst (9:1 1 % P-CDs/TiO2@CS). The photocatalyst exhibited a smaller band gap and a broader light absorption range than TiO2, while the porous structure of the hydrogel increased the contact area between P-CDs/TiO2@CS and Cr(VI), thereby enhancing its photocatalytic performance. Our study demonstrates that under simulated sunlight using a xenon lamp, 0.2 g of 9:1 1 % P-CDs/TiO2@CS reduced 50 mg/L Cr(VI) at a rate of 99.64 % in 30 min (pH 7). The photocatalyst also exhibited excellent reduction capabilities for Cr(VI) across a pH range (pH 2–9), at different concentrations (10, 20, 30, 40, 50, and 60 mg/L), and in various real wastewater samples (influent, effluent, and electroplating wastewater). After five cycles, the reduction rate was still maintained at 90.38 %. Experiments conducted under natural sunlight and ion interference further confirmed its outstanding photocatalytic performance and stability in real-world applications. Free radical trapping experiments indicated that electrons (e-) and holes (h+) were the primary active species. Additionally, antibacterial experiments showed that the reactive oxygen species generated by the photocatalyst under light irradiation effectively inhibited the proliferation ofEscherichia coli. Thus, P-CDs/TiO2@CS holds significant potential for practical application in environmental wastewater treatment.

Porous Bimetallic Ti-MOFs for Photocatalytic Oxidation of Amines in Air.

A family of microporous titanium-containing metal-organic frameworks (denoted as M2Ti-CPCDC, M = Mn, Co, Ni) has been synthesized by using a bimetallic [M2Ti(μ3-O)(COO)6] cluster and a tritopic carbazole-based organic ligand H3CPCDC. M2Ti-CPCDC are stable and display permanent porosity for N2 and CO2 uptake, ranking among the most porous titanium-based metal-organic frameworks. M2Ti-CPCDC crystals exhibit n-type semiconductor behavior. Further catalytic studies demonstrate that all M2Ti-CPCDC materials are applicable for triggering photo-oxidative reactions of amines in air. More specifically, amines with electron-donating groups afford the aldehydes as the main products, while amines bearing electron-withdrawing groups give rise to imines as the main product. Among them, Mn2Ti-CPCDC exhibit the best photocatalytic activity, with conversion of benzylamine up to 99% and selectivity of 99%. Mn2Ti-CPCDC could be recycled in at least three runs while retaining crystallinity and catalytic activity. The reaction mechanism indicates that photoinduced hole (h+), superoxide radical anion (O2·-), and singlet oxygen (1O2) are the main active species involved in the photo-oxidation process.

Heterogeneous Fenton system driven by magnetic graphene-like biochar for degrading tetracycline

In this study, a novel catalyst with high efficiency and low cost was synthesized from farmland waste peanut shells by one-step pyrolysis modification method via K2FeO4, and employed for the catalytic degradation of tetracycline (TC). The magnetic potassium ferrate modified graphene-like biochar catalyst (PFGB) exhibited a high porosity, a highly graphitized structure, and a large specific surface area (857.09 m2·g-1) which was almost 30 times higher compared with peanut shell biochar, and were found to contain more functional groups. The formation and distribution of Fe3O4 and Fe0 nanoparticles on the surface/pores of PFGB provided more active sites for promoting adsorption and catalytic degradation reactions, and accelerated Fe(II)/Fe(III) recycle. Under the optimal conditions (pH=3.5, catalyst dosage = 0.5g·L-1, H2O2 concentration = 10mmol·L-1), about 98% of TC were degraded within 90min when the initial concentration of TC was 150mg·L-1, and PFGB could perform effectively over a wide pH range of 3-6. Furthermore, PFGB exhibited the advantages of convenient magnetic separation and strong reusability, maintaining a TC removal rate of ~90% after five cycles of experiments. The results of free radical quenching experiment and electron spin resonance analysis revealed that •OH and 1O2 were the main active species in the radical and non-radical pathways, respectively. This study indicated that PFGB, a catalyst developed for heterogeneous Fenton-like systems, possessed high efficiency, stability and reusability, and could be promising for the removal of TC in wastewater and other polluted waters.

Boosting lactic acid photocatalytic synthesis from biomass sugars: The synergistic effect of N-doped carbon dots on ultrathin carbon nitride

The green and sustainable production of lactic acid via photocatalytic conversion of biomass-derived sugars is highly significant owing to its enhanced efficiency and reduced energy requirements. Consequently, the investigation has engineered a metal-free photocatalyst (NCDs/CCN), consisting of N-doped carbon dots (NCDs) and ultrathin carbon nitride (CCN). This catalyst has an enhanced light absorption range, facilitating a marked acceleration in the separation rate of photogenerated carriers. It has demonstrated the capability to achieve a lactic acid yield of up to 87.6 % in just 90 min with a mere 20 mg catalyst concentration in a xylose-alkali system. Electron Paramagnetic Resonance (EPR) and quenching experiments indicate that superoxide radicals (·O2−) are the primary oxidizing active species in the photocatalytic system, followed by h+, ·OH, and 1O2. DFT analysis suggests nitrogen doping enhances interaction with xylose, lowering adsorption energy and accelerating lactic acid generation, thus improving economic feasibility and sustainability.

Efficient visible-light-driven photocatalytic degradation of indoor formaldehyde using an indium-based MOF/graphene oxide composite

Formaldehyde (HCHO) severely degrades indoor air quality, and conventional remediation methods are often inadequate for addressing low concentrations of HCHO indoors. In this study, we synthesized a MIL-68(In)-NH2/graphene oxide (GO) composite using a solvothermal method, aimed specifically at enhancing the photocatalytic degradation of HCHO under visible light. Our results show that the integration of GO enhances visible light absorption and facilitates efficient electron transport, significantly improving photocatalytic performance. The MIL-68(In)-NH2/GO composite achieves a 77 % degradation rate of HCHO, significantly outperforming MIL-68(In)-NH2 (51 %) and GO (22 %) alone. This enhanced activity is attributed to the effective separation of electron-hole pairs and synergistic interactions within the composite. We proposed an enhanced photocatalytic mechanism for the MIL-68(In)-NH2/GO system, identifying h+ and •O2– as the principal active species. Moreover, the MIL-68(In)-NH2/GO composite shows excellent reusability and stability, making it a promising candidate for eco-friendly and efficient indoor air purification using metal–organic frameworks.