Visible Conditions Research Articles

Type II photoinitiators with collagen-based cyanine for cell encapsulation under green-red LED

3D bioprinting with cell-laden materials is an emerging technique for fabricating functional tissue constructs. However, current cell-laden bioinks often lack sufficient cytocompatibility with commonly used UV-light sources. In this study, green to red photoinduced hydrogel crosslinking was obtained by introducing synthesized biosafety photoinitiators and used in light-based direct ink writing (DIW) 3D printing for enabling cell encapsulation successfully. The novel type II photointiators contain iodonium (ONI) and synthesized cyanine dyes CZBIN, TDPABIN, Col-SH-CZ, and Col-SH-TD with strong absorption in the range of 400–600 nm. Collagen-based macromolecule dyes Col-SH-CZ and Col-SH-TD showed excellent cytocompatibility. The photochemistry of these photoinitiators revealed an efficient photoinduced electron transfer (PET) process from the singlet excited states of the dyes to iodonium (ONI), facilitating the crosslinking of the biogels. L929 cells were encapsulated in Gel-MA hydrogels containing various photoinitiating systems and exposed to near-ultraviolet, green, or red LED irradiation. DIW-type 3D printing of Gel-MA bioink with L929 cells was also evaluated. The cell viability achieved with green light encapsulation reached 90 %. This novel approach offers promising prospects for bioprinting functional tissues with enhanced cytocompatibility under visible light conditions.

Lewis Acid-Mediated Isothiocyanation and Chlorination of Quinoxalin-2(1H)-ones under Visible Light Conditions.

Lewis acid-mediated selective C3-isothiocyanation of quinoxalin-2(1H)-ones using N-thiocyanatosaccharin as an isothiocyanate source under visible light conditions at room temperature is described. Under similar conditions with N-chlorosaccharin, the C3-chlorination of quinoxalin-2(1H)-ones achieved a 2 h time frame. Good to an excellent yield of products was obtained in both cases with broad functional group tolerance. Control experiments suggest that the reaction proceeds through a radical mechanism. The present procedure demonstrates the applicability at gram-scale reactions and highlights the subsequent conversion of isothiocyanates into representative thiourea derivatives, and one of the chloro derivatives transformed to glycogen phosphorylase inhibitors.

The experience of living with vitiligo in Nigeria: A participatory Interpretative Phenomenological Analysis.

Vitiligo is a visible depigmenting skin condition, particularly noticeable on Black skin. There is widespread misunderstanding of the condition. Using a participatory form of Interpretative Phenomenological Analysis (IPA), we conducted eight semi-structured interviews with Nigerians living with vitiligo. Participants described their initial attempts to understand the condition, which typically drew on both traditional illness beliefs, religious influences, and the biomedical disease model. All participants reported experiencing marked stigmatization and discrimination. Participants experienced distress associated with thoughts about the personal meaning of the disease including its impact on their appearance and from concerns about anticipated and direct discrimination. Despite the wide-ranging impact, the participants' narratives also contained references to the development of strategies that maintained wellbeing. This study provides valuable insights into the role of faith and traditional beliefs in both the experience and management of vitiligo in Nigeria. These insights can be used to develop individual and community interventions.

Synergistic Antioxidant Effects of Cysteine Derivative and Sm-Cluster for Food Applications.

The incorporation of antioxidants in food products is essential to prevent or delay deterioration, thereby addressing food spoilage. Thiol compounds, recognized for their natural antioxidant properties, are widely used in various foods; however, their antioxidant capacity is often limited. This study investigates the potential enhancement of thiol antioxidant capacity through the addition of a soluble, low-toxic inorganic Sm-cluster. Our findings demonstrate that the Sm-cluster significantly bolsters the antioxidant efficacy of thiol compounds. We explored, for the first time, the in vitro antioxidant activities of an Sm-oxo/hydroxy cluster combined with a cysteine derivative for potential food applications. The composition exhibited a robust inhibition of aromatic aldehyde flavor compound oxidation and displayed strong, dose-dependent DPPH (2,2-diphenyl-1-picrylhydrazine) radical scavenging activity. Notably, the antioxidant activity of the Sm-cluster/cysteine derivative was further enhanced under strong visible light conditions, which typically increased the likelihood of oxidation. These results suggest that the combination of inorganic cluster and thiol compounds presents a promising natural alternative to traditional antioxidants in the food industry.

Fe3O4/ZnO/L-lysine functionalized graphene oxide a promising nanocomposite with double Z-scheme visible photocatalytic and dark catalytic activity for water remediation

Developing multifunctional catalysts for efficient pollutant degradation in dark and visible light conditions represents a significant advancement in water remediation technology. This study reports the synthesis of a novel Fe3O4/ZnO/Lys-rGO nanocomposite via environmentally friendly methods that exhibit catalytic-photocatalytic activity for efficient degradation of organic pollutants. The synergistic effect of compositing Lys-rGO, a bio-organic component with a narrow band gap (1.08 eV), into the Fe3O4/ZnO inorganic composite induces a double Z-scheme mechanism by providing two pathways for effective charge separation in the visible photocatalytic activity of the nanocomposite. Additionally, the stored electrons in the very conductive Lys-rGO layers offer active sites for the catalytic activity of the nanocomposite in the dark. Meanwhile, ZnO generates reactive oxygen species (ROS) through surface oxygen vacancies, further contributing to the nanocomposite’s dark catalytic activity. The degradation of various organic pollutants (Methylene Blue, Tetracycline, Ciprofloxacin, Rhodamine B, and their mixture), as well as Congo Red, with low catalyst dosage and visible light irradiation time, demonstrates the high performance and versatility of this nanocomposite. This research highlights the potential of Lys-rGO in compositing with semiconductors to design multifunctional catalysts for cost-effective sustainable water purification technologies.

Photoluminescence of polysiloxane-immobilized lignin-modified wood toward color-tunable and ultraviolet protective smart window

Smart windows can benefit from the use of photochromic wooden materials. In the current study, we report the preparation of fluorescent wood that can switch color under visible and ultraviolet lighting conditions. In order to develop a transparent wood that is both fluorescent and photochromic, a mixture of europium and dysprosium activated strontium aluminum oxide (EDSA) nanoparticles (NPs; 8–13 nm) and room-temperature vulcanizing (RTV) silicone rubber (Polysiloxane) was integrated into a delignified wood. EDSA is known for its excellent photostability and thermal stability. The EDSA phosphor has to be efficiently dispersed in RTV to avoid the formation of aggregates, allowing for a better fabrication of colorless wood. The coloration findings from the CIE Lab parameters displayed that when illuminated with ultraviolet rays, this colorless wooden substrate turned green. Using a transmission electron microscope (TEM), the morphological properties of the synthesized EDSA NPs were examined. Various analysis techniques, including elemental mapping, energy-dispersive X-ray (EDX), X-ray fluorescence spectroscopic analyzer (WDXRF), scanning electron microscope (SEM), hardness testing, and photoluminescence spectra, were employed to study the photochromic woods. An absorption band (365 nm) and two emission bands (436 nm and 518 nm) were determined for the prepared photoluminescent woods. When increasing the EDSA content, the results showed that the produced EDSA-infiltrated wood was more water-resistant and highly protective against UV radiation. Reversible photochromic responsiveness to UV light was observed for the prepared transparent luminous wood without fatigue.

Temporary change in NEXAFS spectra of amorphous carbon nitride films with photoinduced deformation by visible light irradiation

Amorphous carbon nitride (a-CNx) films, prepared by reactive radio frequency magnetron sputtering, exhibit unique characteristics under visible light irradiation, referred to as photoinduced deformation. This phenomenon represents an energy conversion system wherein photon energy transforms into kinetic energy. The chemical bonding structure of a-CNx films was analyzed using near-edge x-ray absorption fine structure (NEXAFS) at the NewSUBARU synchrotron facility of the University of Hyogo, Japan. This analysis aimed to elucidate the mechanisms behind the photoinduced deformation observed in a-CNx films. Three variants of a-CNx films, displaying varying degrees of photoinduced deformation, were deposited using a graphite target and nitrogen gas under different deposition temperatures. The NEXAFS spectra of the a-CNx films with substantial photoinduced deformation showed changes under light irradiation from a Xe lamp (directed through an optical window within the NEXAFS chamber). Specifically, the peaks corresponding to the 1s to π* transition related to C—C and 1s to σ* transition related to C—N bonds exhibited high sensitivity to visible light irradiation. Simultaneously, the N K-edge spectra associated with the 1s to π* transition, attributed to the N—C bond, exhibited a slight intensity decrease. Conversely, the C K-edge spectrum in the a-CNx films displaying minimal photoinduced deformation remained unchanged under visible light irradiation. The N K-edge spectra maintained a consistent shape under both visible light and dark conditions.

Biogenically synthesized porous TiO2 nanostructures for advanced anti-bacterial, electrochemical, and photocatalytic applications

This study develops environmentally benign capping technique to synthesize nanoparticles of Curcuma longa-coated titanium dioxide (CR-TiO2) from titanium isopropoxide by utilizing the extract of Rosa rubiginosa flowers as reducing and chelating agent. The biogenically synthesized nanoparticles revealed excellent anti-bacterial, electrochemical, and photocatalytic properties due to the presence of porous TiO2 nanostructures. The sharp peaks by XRD pattern showed the crystallinity and phase purity of TiO2 nanoparticles. BET analysis proved mesoporous nature of the materials with specific surface area of 134 m2 g −1. The vibrational spectra suggest hydroxyl groups from flavonoids of Curcuma longa acting as functionalizing agent for TiO2 nanoporous structures with visible luminescence, which is proven in fluorescence spectra and is applicable for photocatalytic studies. The anti-bacterial studies showed good inference on TiO2 nanoparticles against Pseudomonas auruginosa and proved it to be an excellent antipseudomonal agent with the oxidative potential. The maximum degradation of phenol red dye in the presence of TiO2 under visible light conditions was observed. The supercapacitor fabricated using the biogenic TiO2 three-electrode system exhibited a specific capacitance of 128 Fg-1 (10 mV s−1), suggesting it as an excellent electrode material. The LSV curve at 50 mV s−1 scan rate showed that oxygen reduction potential (ORR) of CR-TiO2 electrodes was 121 mV. The present study is a new application of nanoparticles in sustainability consideration of the environment as well as a solution to the power crisis with fewer limitations. The well-distinguished antidiabetic and BSA denaturation potential suggests that these porous TiO2 nanostructures can be useful for drug delivery as glucose inhibitors and oral anti-inflammatory drugs with the restriction of adverse side effects.

Riboflavin-Induced DNA Damage and Anticancer Activity in Breast Cancer Cells under Visible Light: A TD-DFT and In Vitro Study.

Targeted treatments for breast cancer that minimize harm to healthy cells are highly sought after. Our study explores the potentiality of riboflavin as a targeted anticancer compound that can be activated by light irradiation. Here, we integrated time-dependent density functional theory (TD-DFT) calculations and an in vitro study under visible light. The TD-DFT calculations revealed that the electronic charge transferred from the DNA base to riboflavin, with the most significant excitation peak occurring within the visible light range. Guided by these insights, an in vitro study was conducted on the breast cancer cell lines MCF-7 and MDA-MB-231. The results revealed substantial growth inhibition in these cell lines when exposed to riboflavin under visible light, with no such impact observed in the absence of light exposure. Interestingly, riboflavin exhibited no/minimal growth-inhibitory effects on the normal cell line L929, irrespective of light conditions. Moreover, through EtBr displacement (DNA-EtBr) and the TUNEL assay, it has been illustrated that, upon exposure to visible light, riboflavin can intercalate within DNA and induce DNA damage. In conclusion, under visible light conditions, riboflavin emerges as a promising candidate with a selective and effective potent anticancer agent against breast cancer while exerting a minimal influence on regular cellular activity.

Constructing dual sulfite-mediated processes via inner-sphere complexation and photogenerated carrier modulation with Hematite/Fe2TiO5 heterojunction for ofloxacin degradation

Hitherto, various sulfite-based advanced oxidation processes have emerged with particular vantages of low cost and potential for efficient contaminant degradation, which still requires increasing strategies for addressing its drawback. To achieve system-neutral feasibility and overcome the limitations, a metal oxide composite catalyst Hematite/Fe2TiO5 integrated with S-scheme heterojunction was constructed for ofloxacin degradation under S(IV)-visible light conditions. Impressively, the as-built system manifested significant promotion on substrate removal (more than four times the original Fe2TiO5), which indicated the accelerated inner-sphere interactions between catalyst and S(IV) with beneficial Vis contributed primarily to the degradation, demonstrating the dual sulfite-mediated effective pathway through modulated photogenerated carriers and oxy-sulfur radical chain reactions. Additionally, the interfacial enhancement by the heterojunction structure was further investigated by First-principles computation, which confirmed the mechanism of facilitated electron-hole pair separation. Overall, this work reveals the critical mechanism of Vis-induced S(IV)-AOP and provides constructive perspectives to address the limitations of conventional processes.

One-Pot Synthesis of Cellulose-Based Carbon Aerogel Loaded with TiO2 and g-C3N4 and Its Photocatalytic Degradation of Rhodamine B.

A cellulose-based carbon aerogel (CTN) loaded with titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) was prepared using sol-gel, freeze-drying, and high-temperature carbonization methods. The formation of the sol-gel was carried out through a one-pot method using refining papermaking pulp, tetrabutyl titanate, and urea as raw materials and hectorite as a cross-linking and reinforcing agent. Due to the cross-linking ability of hectorite, the carbonized aerogel maintained a porous structure and had a large specific surface area with low density (0.0209 g/cm3). The analysis of XRD, XPS, and Raman spectra revealed that the titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) were uniformly distributed in the CTN, while TEM and SEM observations demonstrated the uniformly distributed three-dimensional porous structure of CTN. The photocatalytic activity of the CTN was determined according to its ability to degrade rhodamine B. The removal rate reached 89% under visible light after 120 min. In addition, the CTN was still stable after five reuse cycles. The proposed catalyst exhibits excellent photocatalytic performance under visible light conditions.

Boosting visible-light-driven photocatalysis of nitrogen oxide degradation by Mott–Schottky Pd/TiO2 heterojunctions

One of the main air pollutants is NOx gas, which is emitted into the atmosphere by burning fossil fuels and vehicle exhaust. The application of the photocatalytic technique to mitigate the concentration of NOx in the atmosphere is preferable because it is environmentally friendly, simple, and inexpensive method. In this work, palladium nanoparticles (Pd NPs) were decorated on TiO2 nanotubes (TNTs) by gamma-ray irradiation, and degradation of nitrogen monoxide (NO) was applied to evaluate the photocatalysis of the as-prepared Pd/TNT materials under atmospheric conditions. The results demonstrated that the Pd/TNT material with a 14 kGγ dose is the best photocatalyst, achieving 53.30 % NO removal efficiency, which is 1.6 times greater than that of pure TNTs. Furthermore, the decomposition of NO on the Pd/TNT catalysts also generated less NO2 poisoning under both solar and visible light conditions. Additionally, they possess desirable properties such as reusability, low toxicity, and high apparent quantum efficiency (AQE).

The temporal dynamics of conscious and unconscious audio-visual semantic integration

We compared the time course of cross-modal semantic effects induced by both naturalistic sounds and spoken words on the processing of visual stimuli, whether visible or suppressed form awareness through continuous flash suppression. We found that, under visible conditions, spoken words elicited audio-visual semantic effects over longer time (−1000, −500, −250 ms SOAs) than naturalistic sounds (−500, −250 ms SOAs). Performance was generally better with auditory primes, but more so with congruent stimuli. Spoken words presented in advance (−1000, −500 ms) outperformed naturalistic sounds; the opposite was true for (near-)simultaneous presentations. Congruent spoken words demonstrated superior categorization performance compared to congruent naturalistic sounds. The audio-visual semantic congruency effect still occurred with suppressed visual stimuli, although without significant variations in the temporal patterns between auditory types. These findings indicate that: 1. Semantically congruent auditory input can enhance visual processing performance, even when the visual stimulus is imperceptible to conscious awareness. 2. The temporal dynamics is contingent on the auditory types only when the visual stimulus is visible. 3. Audiovisual semantic integration requires sufficient time for processing auditory information.

Interface-regulated S-type core–shell PCN-224@TiO2 heterojunction for visible-light-driven generation of singlet oxygen for selective photooxidation of 2-chloroethyl ethyl sulfide

Selective oxidation of sulfur mustard gas (HD) to non-toxic sulfoxide by the visible-light-catalyzed generation of singlet oxygen (1O2) is a promising degradation strategy. Although PCN-224 can absorb visible light, it suffers from rapid electron-hole recombination and low redox capacity, which limits the performance of HD degradation. Titanium dioxide (TiO2) is an excellent photocatalyst but it lacks visible-light-activity in degrading HD. In this study, PCN-224@TiO2 heterojunction with S-type core–shell structure was synthesized by in-situ growth method to prolong the visible light absorption capacity of TiO2 and inhibit the rapid recombination of PCN-224. The interface formation and internal electric field were optimized by adjusting the Zr/Ti ratio to enhance the charge transfer, redox capacity, electron-hole separation, and visible light absorption. In this study, the formation of heterojunction composites based on Zr-O-Ti linkages is demonstrated by a series of characterization methods. It is demonstrated by experiments and theoretical calculations that PCN-224@TiO2 can generate nearly 100 % 1O2 under visible light conditions without a sacrificial agent, resulting in efficient and selective oxidation of 2-chloroethyl ethyl sulfide (CEES), a simulant of HD, to non-toxic sulfoxide form.

Synthesis of graphene-based nanocomposites with superior doxycycline removal efficiency and antimicrobial studies

Herein, we report the successful preparation of high-quality graphene (G) nanosheets up to the kg scale using an electrochemical technique using graphite rods from scrap dry cell batteries. The as-prepared graphene was then decorated in-stiu with niobium oxide (Nb2O5) and silver (Ag) nanoparticles to prepare Nb2O5@G and Ag@G nanocomposites. Powdered X-ray diffraction (p-XRD), Fourier-transform (FT-IR) infrared spectroscopy, UV–visible (UV–vis) spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM) were used to characterize the as-prepared nanocomposite material. This binary Nb2O5@G nanocomposite was subsequently used to degrade doxycycline antibiotic with an efficiency of 98.5 % in 120 min under visible light conditions. To determine the optimal scope of the as-prepared composite catalyst, degradation studies were performed at different pH values, photocatalyst doses and temperatures. Kinetics studies revealed that the processes followed pseudo-first-order kinetics. In addition, the as-synthesized graphene, Nb2O5@G and Ag@G nanocomposites were used for selective application against E. coli bacterial strains. Overall, Ag@G has shown good potential application prospects in the development of antibacterial materials in comparison with Nb2O5@G and pristine graphene. This study highlights the potential of as-prepared graphene-based nanocomposites for use in waste treatment and environmental bioremediation.

Degradation of Azo Dye Orange II Using BiOI/HKUST-1 Activated Persulfate under Visible Light Irradiation

Type I semiconductor heterojunction BiOI/HKUST-1 composites were prepared through a solvothermal method, with optimisation of the molar ratio and solvothermal reaction temperature. Comprehensive characterisation was conducted to assess the physical and chemical properties of the prepared materials. These composites were then evaluated for their ability to activate persulfate (PMS) and degrade high concentrations of azo dye orange II (AO7) under visible light conditions. The influence of various parameters, including catalyst dosage, PMS dosage, and initial AO7 concentration, were investigated. The AO7 degradation followed a pseudo-second order kinetic, and under visible light irradiation for 60 min, a degradation efficiency of 94.9% was achieved using a BiOI/HKUST-1 dosage of 0.2 g/L, a PMS concentration of 0.5 mmol/L, and an AO7 concentration of 200 mg/L. The degradation process involved a synergistic action of various active species, with O2−, 1O2, and h+ playing a pivotal role. Both BiOI and HKUST-1 could be excited by visible light, leading to the generation of photogenerated electron-hole pairs (e−-h+); BiOI can efficiently scavenge the generated e−, enhancing the separation rate of e−-h+ and subsequently improving the degradation efficiency of AO7. These findings highlight the excellent photocatalytic properties of BiOI/HKUST-1, making it a promising candidate for catalysing PMS to enhance the degradation of azo dyes in environmental waters.

Enhanced degradation of E2/EE2 by BiPO4/AgI/BC composite photocatalysts via BC-enhanced ·O2-

This study presents the synthesis of highly active BiPO4/AgI/BC composite photocatalysts via a green, simple, and low-cost ambient temperature precipitation method. The electron transfer rate and visible-light responsiveness can be effectively enhanced by utilizing BiPO4 compounded with the semiconductor AgI, which has a narrow bandgap and good visible-light responsiveness. Additionally, the introduction of biocarbon (BC) enhances the absorption and separation of photogenerated electrons and holes under visible light. Notably, the synthesized BP-AgI0.6-BC5 % could remove 99.16 % and 99.7 % of EE2 and E2, respectively, at a concentration of 3 mg/L after 40 min of light exposure. The capture experiments and electron paramagnetic resonance spectroscopy reveal that the main active substance in the system is ·O2-, with BC playing a crucial role in enhancing the ·O2- concentration in the system. The findings from phytotoxicity and antimicrobial tests reveal that BP-AgI0.6-BC5 % can efficiently degrade pollutants, producing degradation products that are substantially less toxic than the original pollutants. Moreover, it can remove more than 99.99 % of E. coli under both dark and light conditions, demonstrating excellent antimicrobial performance. Additionally, the photocatalytic mechanism and degradation pathway were examined in this study. Notably, the composite photocatalysts synthesized in this study achieved efficient degradation of EE2 and E2 under visible light conditions while exhibiting efficient bactericidal function. Furthermore, the room-temperature preparation method is conducive to industrial-scale production, highlighting a better prospect for practical applications.

Enhanced oxygen anions generation on Bi2S3/Sb2S3 heterostructure by visible light for trace H2S detection at room temperature

Bismuth sulfide (Bi2S3) possesses unique properties that make it a promising material for effective hydrogen sulfide (H2S) detection at room temperature. However, when exposed to light, the oxygen anions (O2–(ads)) adsorbed on the surface of Bi2S3 can react with photoinduced holes, ultimately reducing the ability to respond to H2S. In this study, Bi2S3/Sb2S3 heterostructures were synthesized, producing photoinduced oxygen anions (O2–(hv)) under visible light conditions, resulting in enhanced H2S sensing capability. The Bi2S3/Sb2S3 heterostructure sensor exhibits a two-fold increase in sensing response to 500 ppb H2S under in door light conditions relative to its performance in darkness. Additionally, the sensing response of the Bi2S3/Sb2S3 sensor (Ra/Rg= 23.3) was approximately five times higher than pure Bi2S3. The improved sensing performance of the Bi2S3/Sb2S3 heterostructures is attributable to the synergistic influence of the heterostructure configuration and light modulation, which enhances the H2S sensing performance by facilitating rapid charge transfer and increasing active sites (O2–(hv)) when exposed to visible light.

Enhanced removal of pesticide micropollutant and bacteria using solar light-assisted Ag-doped TiO2: prospects for environmental and health impacts.

Pesticide micropollutants like 4-chlorophenol (4CP) and E. coli bacteria represent a substantial hazard, impacting both the environment and human health. This study delves into the effectiveness of Ag-doped TiO2 (Ag@TiO2) in removing both 4CP and E. coli. Ag@TiO2 has demonstrated remarkable effectiveness in removing 4CP under both solar and visible light conditions, earning degradation efficiencies of 91.3% and 72.8%, respectively. Additionally, it demonstrates outstanding photodegradation efficiency for 4CP (98.8%) at an initial concentration of 1mgL-1. Moreover, Ag@TiO2 exhibited substantially higher removal performance for 4CP (81.6%) compared to TiO2 (27.6%) in wastewater. Analysis of the radicals present during the photodegradation process revealed that ·O2- primarily drives the decomposition of 4CP, with h+ and ·OH also playing significant roles in the oxidation reactions of the pollutant. Interestingly, even under dark conditions, Ag@TiO2 exhibited the capability to eliminate approximately 20% of E. coli, a percentage that increased to over 96% under solar light. In addition, the prospects for environmental and health impacts of utilizing Ag@TiO2 for pesticide micropollutant removal and bacteria were discussed.

Terminalia catappa leaf extract as a bio-reducing agent to synthesize Cu2O nanoparticles for methylene blue photodegradation

The large tree species Terminalia catappa is a member of the Combretaceae family and is mainly found in tropical climates. They are commonly cultivated for shade because they have huge, dense foliage. Numerous polyphenols, including flavonoids, tannins, saponins, and phytosterols, are present in the leaves. In this study, the green chemical method was used to extract polyphenols from dried green almond leaves. They were employed in the synthesis of Cu2O nanoparticles as a reducing agent. FTIR and UV–Vis were used to describe the leaf extract of Terminalia catappa after the chlorophyll was removed. Copper salt was used to create Cu2O nanoparticles via a reduction process. The extract's potential for photocatalytic dye degradation has also been explored. The obtained Cu2O had a spherical shape with dimensions of 50–100 nm, and its band gap energy reached 1.945 eV to remove methylene blue from aqueous media under visible light irradiation conditions. At an initial MB concentration of 10 ppm, the decomposition efficiency reached 71.99% after only 2 h of exposure to simulated sunlight. The decomposition process occurred according to a pseudo-first-order kinetic model with a rate constant of 0.0084 min−1.