We investigated the adsorption behavior and fluorescence properties of 7-methylguanosine (m7Guo), a cationic nucleoside, on clay minerals under acidic conditions. The fluorescence quantum yield Φf was 0.011 in water and 0.126 in a clay dispersion. We observed Surface-fixation-induced emission (S-FIE)—a phenomenon in which fluorescence is enhanced upon adsorption of molecules onto clay mineral surfaces—in this nucleic acid-related molecule. Analysis of the factors contributing to fluorescence enhancement revealed that suppression of the nonradiative decay rate constant knr plays a key role. The value of knr decreased to approximately 1/27 of that in water, indicating that strong immobilization on the clay surface suppresses nonradiative relaxation and stabilizes the excited state.
Ambient-pressure photoemission spectroscopy in air enables the determination of work function of wide-band-gap n-doped semiconductors, like ZnO or TiO2. Oxygen (air) increase the ZnO work function, while the (000−1) O-terminated polar face has regularly larger work function than the (0001) Zn-terminated one. In acetonitrile electrolyte solution, the Zn-(0001) face provides larger photocurrents under UV-light and lower onset potentials, compared to the O-(000–1). A totally opposite activity is observed in aqueous electrolyte solution. The main photoelectrochemical process in dry acetonitrile is ZnO dissolution, but single crystals and thicker films (>600 nm) provide stable and thickness-independent photocurrents at the timescale of several potential sweeps. Operando Raman spectroelectrochemistry detects only ZnO and acetonitrile modes in the dark and upon UV-photoexcitation within a broad array of applied voltages positive to the flatband potential. This supports a simple photocorrosion mechanism producing just Zn2+ and O2, without any byproducts.
Multifunctional nanoplatforms capable of integrating therapy and imaging functions are of significant interest for cancer research. In this work, we report the synthesis of bovine serum albumin (BSA)-functionalized manganese ferrite nanoassemblies (MnFe2O4@BSA NAs) as a multifunctional platform for chemo-photodynamic therapy and magnetic functionality. Ethylenediamine-modified MnFe2O4 nanoassemblies were first prepared via a thermal decomposition route and subsequently conjugated with BSA to improve aqueous stability, biocompatibility, and drug-loading capability. The resulting nanoassemblies exhibited well-defined morphology (50–60 nm), good colloidal stability, and superparamagnetic behavior that was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, zeta-potential, DLS and magnetic measurements. The anticancer drug doxorubicin hydrochloride (DOX) and the photosensitizer Rose Bengal (RB) were successfully loaded into MnFe2O4@BSA NAs, showing high loading efficiency and pH-responsive DOX release. Under visible-light irradiation, RB-loaded MnFe2O4@BSA NAs generated reactive oxygen species (ROS) through combined photodynamic and photo-Fenton-like processes. In vitro studies using MCF-7 breast cancer cells demonstrated that the combined RB-DOX-loaded MnFe2O4@BSA NAs exhibited enhanced cytotoxicity under light irradiation compared to individual chemotherapy or photodynamic therapy, indicating a synergistic chemo-photodynamic effect. Moreover, MnFe2O4@BSA NAs showed good heating efficacy under an AC magnetic field and significant signal reduction on the T2-weighted phantom image with transverse relaxivity (r2) of 123.7 mM−1 s−1. Overall, this study presents MnFe2O4@BSA NAs as a multifunctional in-vitro platform integrating drug delivery, photodynamic activity, magnetic heating, and MRI contrast properties, providing a foundation for future image-guided and in vivo therapeutic investigations.
This study reports four acidity constants of the anticancer drug doxorubicin (DOX) and its order of deprotonation, which have not been reported previously; a mathematical model has also been proposed to predict the percentage of DOX intercalation over laponite clay (Lap) at different pH values. The pKa values were determined experimentally and using the Stability Quotients from Absorbance Data (SQUAD) software, whilst the order of deprotonation was determined using Density Functional Theory (DFT). The calculated pKa values were: 8.38 ± 0.11, 10.29 ± 0.10, 11.05 ± 0.07, and 13.90 ± 0.03 with proton loss beginning at the primary amine, followed by two protons located in the hydroxylated anthraquinone structure, and finally from the short side chain with a carbonyl group. The interaction between DOX and Lap was also studied using UV–vis spectrophotometry and electrochemical techniques. Using spectrophotometry, the logarithms of the binding constants (log Kcond) corresponding to the DOX-Lap complexes were calculated: 5.039 ± 0.009, 4.845 ± 0.002, and 4.618 ± 0.010 at pH values of 1.50 ± 0.01, 7.40 ± 0.01, and 12.50 ± 0.01, respectively. From the log Kcond graph versus pH, a linear relationship “log Kcond = −0.0351*pH + 5.0952” was obtained, used to construct a three-dimensional diagram (molar percentage-pLap-pH) to predict the percentage of DOX intercalation. The high affinity of DOX for this nanoclay was confirmed through cyclic voltammetry. This knowledge may be used to improve the experimental design of controlled-release nanoparticle systems in which clays are used as carriers.
Currently, effective methodologies for systematic regulation of the emission bandgap of carbon quantum dots with aggregation-induced emission (AIE-CQDs) are lacking. Similarly, the aggregation-caused quenching (ACQ) phenomena in solid-state fluorescence, resulting from the π-π stacking interactions or excessive resonance energy transfer (ET) cannot be prevented also. Herein, we demonstrate the synthesis of aggregation-induced emission (AIE) carbon quantum dots (Ds-CQDs) with anti-ACQ characteristics via a post-synthetic modification strategy that can control the functionalization process of disulfide bonds on the surface of CQDs. The AIE behavior and mechanism were investigated via experiments and exhaustive characterization methods. The Ds-CQDs were hydrophobic and exhibited green-yellow dispersed emission and red aggregation-induced emission. The restriction of vibration-rotation of the disulfide bonds caused by π-π stacking interactions and the formation of self-assembled J-aggregates driven by the hydrogen bonding were both confirmed to be responsible for the AIE behavior of Ds-CQDs. Successful utilization of the Ds-CQDs in ink anti-counterfeiting, latent fingerprint identification, and thin film fabrication highlighted their broad application prospects.
The widespread discharge of synthetic dyes into aquatic environments poses a significant threat to both ecological balance and human well-being, underscoring the urgent need for effective and sustainable treatment approaches. A composite material combining CoAl2O4 and CoS was prepared to remove Brilliant Green (BG). The new CoAl2O4@CoS photocatalyst was obtained through a hydrothermal synthesis. The structural and physicochemical properties of these materials were examined by XRD, FTIR, XPS, SEM-EDS, and UV–Vis DRS, which confirmed their crystalline phases, surface composition, oxidation states, and optical characteristics. Photocatalytic tests under simulated sunlight demonstrated that the 1 g/L of CoAl2O4@CoS composite could completely degrade a 20 mg/L BG solution within 70 min. Its apparent rate constant (k = 0.0434 min−1) was significantly higher than those of CoAl2O4 (k = 0.0059 min−1) and CoS (k = 0.0091 min−1). Radical scavenging experiments indicated that hydroxyl radicals (•OH) and superoxide anions (O₂•-) played dominant roles in the degradation reaction. The composite retained its efficiency after five consecutive cycles, confirming its stability and reusability. Density functional theory (DFT) calculations supported the experimental results, showing favorable band positions and orbital hybridization responsible for the enhanced sunlight response. Overall, these findings demonstrate that CoAl2O4@CoS is a promising photocatalyst for solar-assisted wastewater purification.
Photothermal-assisted photocatalysis is regarded as a promising approach for removing harmful algae in water bodies due to its high efficiency and environmental friendliness. However, current photocatalysts suffer from problems such as weak photothermal effect and insufficient solar energy utilization. In this work, flower-like CuS/BiOBr microspheres were deposited on carbonized corn cob (CC) with the assistance of polydopamine (PDA) to construct a novel floatable photocatalyst (CuS/PDA/BiOBr@CC). Under visible light irradiation, the surface temperature of CuS/PDA/BiOBr@CC can be elevated to 107.2 °C. The photocatalyst exhibited excellent photocatalytic efficiency in algae removal, with 99.7% of Microcystis aeruginosa (OD680 = 0.8) being inactivated after 180 min of visible light irradiation. This high efficiency is attributed to the photothermal effect and heterojunction interface of the catalyst, which can not only promote the light-harvesting ability, but also accelerate the spatial separation and transport of photogenerated charge carriers. By combining DFT calculations with band bending theory analysis, it was revealed that the internal electric field at the heterojunction interface between CuS/PDA and BiOBr triggered the S-scheme charge transfer pathway. Furthermore, radical quenching experiments and ESR analysis confirmed that the reactive oxygen species, including •O2−, 1O2 and •OH, played significant roles in algae inactivation. The CuS/PDA/BiOBr@CC also exhibited outstanding cyclic stability and practical applicability in photocatalytic inactivation of Microcystis aeruginosa. This work offers a useful strategy for the rational design of floatable S-scheme heterojunction photocatalysts and provides novel insights into photothermal-assisted photocatalysis technology for the remediation of cyanobacterial blooms
The oxidative coupling of methane (OCM) offers a promising route for directly upgrading abundant natural gas to value-added C2 hydrocarbons. However, conventional OCM requires high operating temperatures, which impose substantial energy penalties, complicate reactor design, and limit practical viability. Recently, photocatalytic OCM has emerged as an alternative approach for enabling methane activation under milder conditions by integrating catalytic reactions with light-driven processes. Despite rapid progress, reported performances remain difficult to compare, and the energy relevance of many systems is often unclear. Unlike broader reviews of photocatalytic methane conversion, this review focuses specifically on photocatalytic and photo-assisted oxidative coupling routes to C2 hydrocarbons. It evaluates the field through an integrated framework linking catalyst architecture, reactor configuration, and energy-relevant benchmarking metrics. Key photocatalyst architectures, including semiconductor-based systems, plasmon-enhanced materials, single-atom and nanoalloy catalysts, and lattice‑oxygen-mediated catalysts, are analyzed in terms of methane activation pathways, C2 selectivity, over-oxidation suppression, and stability. In parallel, batch and continuous-flow reactor configurations are evaluated with respect to irradiation management, heat transfer, residence-time control, product withdrawal, and scalability. Particular attention is given to the limitations of percentage-based performance metrics and the importance of rate-based, photon-aware, and stability-related benchmarks for meaningful cross-study comparison. By integrating catalytic, photochemical, and reactor-level perspectives, this review addresses a central knowledge gap in photocatalytic OCM: how photocatalyst architecture, active‑oxygen or lattice‑oxygen control, methyl-intermediate management, and reactor-level operation collectively determine C2 selectivity, stability, and scalability under mild conditions.
The quest for sustainable energy and environmental remediation necessitates highly efficient photocatalytic systems. Traditionally, the discovery and optimization of photocatalysts rely on laborious trial-and-error experimental approaches and computationally intensive theoretical calculations. However, the advent of Artificial Intelligence (AI) and Machine Learning (ML) has introduced a transformative paradigm, offering unprecedented opportunities to accelerate photocatalytic research and enhance performance. This review comprehensively surveys the burgeoning landscape of AI and ML applications in photocatalysis, highlighting their potential to revolutionize material design, reaction optimization, and mechanistic understanding. Recent advances in AI and data science are revolutionizing the discovery of materials for photocatalysis and environmental science. These technologies predict material and various physicochemical properties of photocatalysts, such as optical, electronic, and thermal properties, optimize reaction conditions, and guide the design of advanced heterostructures and enhance modification strategies for better charge transfer, while AI and ML enable real-time control, cutting experimental time, cost, and energy use. Additionally, they enable accurate dispersion predictions, optimize reaction conditions, accelerate literature-based simulations, and support robust evaluations of energy efficiency. AI/ML integration accelerates next-generation photocatalyst development by replacing trial-and-error with data-driven methods. This review critically examines the current landscape, highlights promising research directions, and advocates wider AI/ML adoption for sustainable photocatalysis.
Photodynamic therapy (PDT) is a promising minimally invasive treatment modality for cancers, yet its efficacy is often limited by the properties of current photosensitizers. A series of novel asymmetrical AB3-type porphyrins (P1–6) bearing amino acid residues was designed and synthesized to improve the efficacy of photodynamic therapy (PDT). All derivatives exhibited the characteristic porphyrin soret band at 419 nm and four Q-bands, with a key red-region absorption peak at ∼650 nm which is beneficial for deep-tissue penetration. Upon 417 nm excitation, they emitted fluorescence at ∼659 and ∼ 714 nm, with quantum yields Φf ranging from 0.11 to 0.14. Reactive oxygen species assays using DPBF and DHR123 demonstrated that P3 uniquely generates both singlet oxygen and superoxide via complementary type II and type I pathways that induces potent, light-dose–dependent apoptosis. Confocal laser scanning microscopy in Eca-109 cells revealed that P3 localizes in multiple organelles. In vivo fluorescence imaging in tumor-bearing nude mice indicated that P3 exhibited excellent tumor-targeting accumulation and suppressed Eca-109 xenograft growth upon 650 nm irradiation, which outperforming the clinical photosensitizer HMME without observable systemic toxicity. Histological (H&E, TUNEL) analyses corroborated extensive tumor apoptosis, underscoring the potential of P3 as a dual-mechanism photosensitizer for highly effective and safe PDT.
Interface engineering at the perovskite/electron transport layer (ETL) junction has been demonstrated as an effective strategy for achieving high-quality interfacial contact in perovskite solar cells (PSCs). In this work, an n-type dimeric organic molecule, B2, is employed as an interfacial modifier to regulate the contact property between the perovskite layer and PCBM ETL. Experimental results reveal that the B2 interlayer passivates defects in the perovskite layer through coordination with undercoordinated Pb2+ ions, thereby suppressing trap-assisted non-radiative recombination. Furthermore, the B2 modification optimizes the Energy level alignment at the interface, promoting efficient charge carrier transport. As a result of these synergistic effects, the interface-engineered PSCs achieve a power conversion efficiency of 20.20% and maintain over 80% of their initial efficiency after 1056 h of aging tests. This study provides an effective interfacial regulation approach for developing highly efficient and stable PSCs.
