Metal-organic frameworks (MOFs) often show limited selectivity for photocatalytic carbon dioxide redox reaction (CO2RR) due to strong proton affinity at metal site, which kinetically favors the competing hydrogen evolution reaction (HER), along with poor intermediate stabilization and rapid charge recombination. Herein, we introduce amine (-NH2) functionalization into a chromium-based MOF (Cr-MIL-101) (MIL = Material Institute Lavoisier), enables to facilitate strong hybridization between Cr-3d and CO2 pi* orbitals near the Fermi level, promoting direct metal-to-ligand back donation and overcoming the Cr-proton interaction and activates CO2 at Cr+3. To address the high electron recombination rate in NH2-Cr-MIL-101, it is integrated with g-C3N4 to form Sscheme heterojunction. Combined experimental and density functional theory (DFT) analyses reveal that -NH2 groups in Cr-MIL-101 linkers function as dynamic proton relays, reversibly switching between -NH2 and -NH3+ states to shuttle protons directly to the stable Cr3+-activated CO2 sites. This targeted delivery stabilizes the key *COOH intermediate and suppresses the HER, while the g-C3N4 acts as a secondary proton reservoir, ensuring continuous relay reversibility. Transient absorption spectroscopy confirms a 55% increase in photoexcited charge lifetime and suppressed recombination within the heterojunction. These results correspond to 97.8% CO selectivity, 0.25% solar energy to fuel conversion efficiency, and kinetic isotope effect (KIE = 2.3) confirms that the proton is the rate-determining step. This work establishes linker-directed electronic and protonic reconfiguration as a general design principle for controlling proton-coupled electron transfer in molecular photocatalysts.

The long-term stability of methylammonium lead iodide (MAPbI(3)) perovskite remains a critical challenge for its widespread adoption in optoelectronic devices, particularly solar cells. This study investigates the impact of humidity on the degradation kinetics of MAPbI(3) under controlled relative humidity (RH) conditions ranging from 23% to 93%. Time-dependent X-ray diffraction, Raman mapping, and UV-vis spectroscopy were employed to monitor structural, vibrational, and optical changes during degradation. At low humidity (up to RH 35%), the material remains relatively stable for over 500 h with minimal degradation (similar to 5%). However, at moderate humidity (RH 64%), a two-step degradation process is observed, with an initial rapid decline (similar to 25% in the first 100 h) followed by a slower decomposition. High humidity (RH 85%-93%) accelerates degradation, leading to complete breakdown within 12 h due to hydrolysis and structural instability. Kinetic modeling reveals that the second-order reaction mechanism best describes moderate RH 64% conditions with the highest R-2 values (0.996) and reaction rate constant of 0.0044 mol(-1)dm(3)h(-1), indicating that the degradation rate is proportional to the perovskite concentration square. Machine learning (ML) and artificial neural network (ANN) models were implemented to predict the degradation behavior of MAPbI(3) using experimental data. ANN achieved superior predictive accuracy across training, testing, and validation sets (R-2 = 0.958, 0.987, and 0.969, respectively), demonstrating the model's capacity to predict perovskite stability under various environmental conditions.

Herein we report on the synthesis, crystal structure, vibrational and optoelectronic properties as well as DFT calculations of the air stable lead free TMS3M2I9 (TMS = (CH3)3S; M = Bi, Sb) perovskite halides. These compounds were synthesized with high purity using solid-state and solution methods by reacting MI3 and (CH3)3SI. Hexagonal, P63mc (No. 186), crystal structures of both compounds were confirmed at 393 K by single crystal Xray Scattering and Rietveld analysis with a 0D network of [M2I9]3- dimer structure. TMS3M2I9 hexagonal undergoes structural phase transitions to the monoclinic crystal, twinning in the space group C121 (#5), at room temperature of 298 K. Investigation of lattice and molecular vibrations performed by Raman spectroscopy in the temperature range of - 190-180 degrees C indicated the presence of hexagonal and monoclinic phases and confirmed the robustness of the synthesized materials related to the high stability of the trimethyl sulfonium cation in the perovskite framework. Band gaps of 2.1 eV and 2.3 eV were experimentally determined for the Bi- and Sbcontaining perovskites, respectively. First-principles calculations were conducted to assess the energy band gap values, electronic structure, and density of states, yielding results consistent with the experimentally determined values. The new compounds were successfully incorporated in DSSCs, justifying their broad application potential.

The present work introduces the 3GPV-4INDUSTRY flagship project, one of the emblematic actions currently implemented in Greece in twelve (12) interdisciplinary scientific areas with a special interest in the connection with the productive sector. These flagship actions are funded by Greece 2.0 – National Recovery and Resilience Fund/Next Generation EU and are addressed to research and knowledge dissemination organizations, which carry out economic activities. The main objective of the actions is to strengthen collaborative research projects of interdisciplinary nature, of high scientific and technological quality, with the aim of integrating research and innovation into the productive fabric of the country and stopping the "brain drain". The 3GPV-4INDUSTRY flagship project focuses on advanced materials for energy and especially their use for the development of efficient third generation photovoltaic (PV) devices to enhance the competitiveness of enterprises to the green energy production.

In this study, a hydroxylamine (HA)-enhanced magnetic spinel catalyst CuFe2O4-activated peroxymonosulfate (PMS) system (CuFe2O4/PMS/HA) was constructed to degrade Sulfamethoxazole (SMX). Results from experiments and theoretical calculations indicated that active species generation mechanism involved the direct activation of PMS by HA, the redox cycles acceleration on the surface of CuFe2O4 by HA, and the synergistic action of the low valence Fe and Cu species in CuFe2O4 for PMS activation. The efficacy of other organic pollutants removal was further validated in bio-treated landfill leachate through removal performance and toxicity assessment. This study provided an understanding of the role of HA and its interactions with Cu-Fe bimetals to activate PMS, advancing our understanding and inspiring the application of similar spinel/reductants/PMS systems.

This study presents an integrated strategy to optimize biofuel production from Chlorella sorokiniana (CSO) and Chlorella vulgaris (CVU) by combining salt-induced stress and thermal pretreatment. The microalgae were cultivated in anaerobic digestate effluent (ADE) under stress and non-stress conditions to evaluate nutrient availability’s impact on biomass composition. Salt stress significantly enhanced lipid accumulation, with CVU exhibiting a 51.6% increase. Thermal pretreatment of biomass at 90 °C for 10 h achieved the highest methane yield (481 mL CH4/g VS), with CVU outperforming CSO. Milder pretreatment conditions (40 °C for 4 h) were more energy-efficient for CSO, achieving a yield of 2.67%. Fatty acid profiles demonstrated species-specific biodiesel properties, with CSO rich in oleic acid (33.47%) offering enhanced oxidative stability and cold flow performance, while CVU showed a higher polyunsaturated fatty acid content. This research highlights the economic viability of using ADE as a low-cost cultivation medium and the potential for scalable thermal pretreatments. Future research should focus on reducing energy demands of pretreatment processes and exploring alternative stress induction methods to further enhance biofuel yields. These findings offer valuable insights for tailoring cultivation and processing strategies to maximize lipid and methane production, supporting sustainable and economically viable dual biofuel production systems.

This study presents a comprehensive investigation into the synthesis and characterization of TiO2 coatings on glass substrates, focusing on the development of superhydrophilic, self-cleaning titania coatings using the hydrosol approach. Stringent cleaning protocols were accurately followed to ensure the pristine condition of glass surfaces prior to deposition. Various organic precursor solutions were precisely prepared and applied to the glass substrate via dip-coating, followed by subsequent thermal treatment. A range of characterization techniques, including Raman spectroscopy, UV/Vis spectroscopy, scanning and atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle measurements, were employed to assess the properties of the coatings. The results revealed that the samples were influenced by precursor concentration and withdrawal rate, with slow speed leading to minimal alteration of transmittance. The coatings show superhydrophilic properties, as evidenced by contact angle values below 3 degrees for the thinnest films. Their thickness is approximately 13 nm with very low roughness, indicative of a smooth and uniform surface. Optimization of the deposition conditions permits the fabrication of uniform and transparent TiO2 coatings on glass substrates, offering promising opportunities for the practical use of photoinduced self-cleaning surfaces in real-life applications. Finally, a cost analysis of scaling up the coating and mirror fabrication processes confirmed the economic feasibility of this approach for concentrated solar power (CSP) applications.

Photovoltaic (PV) technology plays a significant role in renewable energy research, while devices based on hybrid perovskite materials have reached efficiencies which exceed 26 %. Nevertheless, perovskite solar cells (PSCs) are facing chemical, thermal and humidity stability issues, which prevent their commercialization. Thus, the use of quantum dots (QDs) has been proposed as an innovative strategy to tackle with device performance issues. This work investigates the effect of PbS and CdS chalcogenide QDs on the interface modification of CsFAMAPbI3-xBrx PSCs. The successive ionic layer adsorption and reaction (SILAR) method was employed as an innovative engineering approach to adjust effectively the perovskite interface energetics and optimize the solar cell's characteristics. By tuning the deposition conditions of QDs and adding TiCl4 to the electron transport layer (ETL), an efficiency improvement from 15.52 to 18.83 % was recorded. These results highlight the use of a facile and fast method to integrate chalcogenide quantum dots into perovskite-based optoelectronic devices, thus improving the surface crystallinity and overall device performance.

Industrial activities generate enormous quantities of polluted effluents, necessitating advanced methods of wastewater treatment to prevent potential environmental threats. Thus, the design of a novel photocatalytic reactor for industrial water decontamination, purification, and reuse is proposed as an efficient advanced oxidation technology. In this work, the development of the active reactor components is described, utilizing a two-step sol–gel technique to prepare a silica-titania trilayer coating on 3D-printed polymeric filters. The initial dip-coated SiO2 insulator further protects and enhances the stability of the polymer matrix, and the subsequent TiO2 layers endow the composite architecture with photocatalytic functionality. The structural and morphological characteristics of the modified photocatalytic filters are extensively investigated, and their performance is assessed by studying the photocatalytic degradation of the Triton X-100, a common and standard chemical surfactant, presented in the contaminated wastewater of the steel metal industry. The promising outcomes of the innovative versatile reactor pave the way for developing scalable, cost-effective reactors for efficient water treatment technologies.

Lead-free chalcogenide perovskites, such as BaZrS3, manifest as strong candidates to replace toxic metals-containing halide perovskites in optoelectronic applications, but the formation of high-quality films for photovoltaic applications remains a major challenge for now, since very high temperatures are needed to fully crystalize the compound. To circumvent this issue, liquid-phase synthesis, through direct fabrication of perovskite nanocrystals dispersed in an organic solvent or a conversion of a pre-crystalline powder to an ink, has been suggested as a viable strategy for low-temperature processing. However, both cases result in films which cannot be used in the fabrication of solar cells. Herein, in this work, we adopt the latter approach, and convert BaZrS3 particles, from solid-state synthesis to a stable colloidal dispersion in a 1-Methyl-2-pyrrolidone (NMP)-oleylamine (OA) mixture. We report a detailed identification of the structural changes of this transformation with a large range of crystallographic, spectroscopic and microscopic techniques. Then, we evaluate the feasibility of the process for the fabrication of films. BaZrS3 infiltrated in mesoporous TiO2/FTO transparent glass substrates were used as photolectrodes in solar cells and proof-of concept devices were constructed in conjunction with I3-/I- redox electrolyte for the first time in literature, reaching a mean PCE of 0.11% and a FF of 61%. We believe that this work will pave the way towards the systematic use of BaZrS3 (or other similar chalcogenide perovskites) in solar cells and other relevant optoelectronic devices.

The global financial impact of soiling on solar power plants is enormous. Anti-soiling coatings offer a promising alternative to reduce labor expenses, minimize water usage, and deter soiling. However, most commercial coatings do not meet the requirements of contemporary solar power applications. This study presents a simple method for developing ambiently cured transparent hydrophobic anti-soiling coatings for PV modules and CSP mirrors based on quaternarized silica hybrids. The coatings were examined in terms of surface energy, microstructure, durability, transmittivity, and reflectance. The soiling rate during real-field exposure was also evaluated. It was found that the proposed coatings present a promising alternative to contemporary anti-soiling strategies by being able to be periodically rejuvenated during regular maintenance of solar power plants, thus ensuring sustained functionality over an extended period.

The simultaneous improvement in the performance and stability of the perovskite solar cells (PSCs) remains a key challenge toward their commercialization. Herein, we explore the ionic liquid 1-hexyl-3-methylimidazolium iodide (HMImI) for the synthesis of a lead halide derivative, namely, (HMIm)PbI3. According to single-crystal X-ray analysis, (HMIm)PbI3 forms 1D chains of face-sharing [PbI6]4-octahedra and behaves as a semiconductor with a band gap of 2.85 eV. This compound, when deposited on top of the main 3D perovskite (Cs/FA/MA)PbI3-xBrx, passivates the surface of the absorber by lowering the density of the trap states, thus enhancing the radiative recombination and the open circuit voltage. In addition, the hydrophobic character of the alkyl chain of the imidazolium cation prohibits the penetration of the humidity and at the same time prevents ion migration from and toward the main perovskite absorber. Furthermore, the PSCs based on this 3D/1D solar cell architecture achieved a power conversion efficiency (PCE) of almost 20% and retained practically 80% of their initial efficiency after 1700 h of storage under dark and ambient conditions, outperforming the corresponding 3D reference device. This is attributed to the high quality of the perovskite layer, as confirmed by grazing-incidence wide-angle X-ray scattering, scanning electron microscopy, atomic force microscopy, and contact angle measurements. The obtained results clearly indicate that the dimensionality engineering approach involving ionic liquids with the appropriate choice of the organic cation is a very promising strategy for improving the efficiency and stability of the perovskite solar cells.

The disinfection properties of photocatalysis on liquid digestate derived from biogas plants have been investigated for the first time. The study presents the physiological characteristics of liquid digestate retrieved from various biogas plants based in northern Greece, revealing the heterogeneity of this matrix. Preliminary photocatalysis experiments conducted on inoculated liquid digestate samples showed that disinfection was possible when a pre-treated digestate underwent a combination of centrifuge–flocculation–μfiltration after 5.5 h with 0.7 g/L suspended TiO2 under UVA illumination. To explore the feasibility of an industrial application based on this concept, a novel design photocatalytic nanofiltration reactor was implemented for disinfection experiments on pre-treated liquid digestate. The synergistic action of photocatalysis during nanofiltration alleviated the leakage phenomena, and both the retentate and permeate effluents had lower concentrations of pathogens by approximately 1–2 log10 cfu/mL. This work sets out the basis for the efficient operation and engineering application of collaborative technology, with photocatalysis as the final step for liquid digestate sanitation and reusable water recovery.

To prevent the degradation of perovskite solar cells (PSCs) and optimize the solar energy conversion process, a donor–π–acceptor (D–π–A) organic blue dye as a passivation layer and as a hole‐transporting layer is introduced. The terminal chains of D–π–A dye confer the ultrahydrophobic character (contact angle > 100°) of the interface layer, protecting the perovskite from ambient moisture while mitigating ionic diffusion in the device. The dye interlayer primarily improves the perovskite by reducing grain boundary defects. The perovskite/D–π–A architecture enhances the interfacial hole extraction, suppressing nonradiative carrier recombination and enabling power conversion efficiency (PCE) reaching 20.90%, outperforming by 2.05% the PCE of control cells. Unsealed PSCs retain 84% and 62% of their efficiency after photovoltaic operation for 1000 and 3000 h, respectively. Statistical correlation of bivariant and multivariant analyses of photovoltaic parameters is performed and Pearson's correlation identifies underlying patterns in experimental data collections. Machine learning (ML) of regression algorithms is used to predict the minimum errors and the coefficient of determination, which confirm the analysis quality. The linear regression ML model suggests the importance of photovoltaic parameters (Rs > Vmpp > Jsc > Voc > fill factor > Jmpp > Rsh) toward higher PCE. An efficient online prediction model is also developed to support the estimation of PCEs with high accuracy.

Halide perovskite compounds have become a major research topic in the semiconductor field due to a variety of optoelectronic applications and their advantage of low-cost and simple processing methods, combined with tunable properties. The current work presents the use of (NH 2 ) 2 CHPbBr 3 (FAPbBr 3 ), with a direct band gap of 2.17 eV, as a robust visible-light detector. The polycrystalline material was prepared by fusion of the precursor compounds PbBr 2 and (NH 2 ) 2 CHBr in solid state. It was then pressed in the form of a pellet and two transparent fluorine-doped tin oxide glasses were attached on both sides. The photodetector selectively responds to photon energies exceeding its band gap even without external bias, operating in an energy-efficient, self-powered mode. The response times to pulsed light are orders of magnitude shorter than these of previously reported FAPbBr 3 -based detectors. Electrochemical impedance spectroscopy determined in depth the electrical characteristics of the semiconducting perovskite with and without illumination. These results provide evidence that polycrystalline FAPbBr 3 , obtained with low-cost and simple synthetic methods compared to other forms, can be an excellent candidate for fast and self-powered optoelectronics, useful for Visible Light Communication (VLC) and Internet of Things (IoT) systems. Display Omitted • Polycrystalline FAPbBr 3 is prepared by fusion of PbBr 2 and FABr in solid state. • The FTO/FAPbBr 3 /FTO photodetector shows high selectivity in the range 500–600 nm. • The device operates as an energy-efficient, self-powered photodetector. • Orders of magnitude shorter response times compared to other FAPbBr 3 photodetectors.

Organic wastes and by-products from several activities, including food industries, farming, and animal husbandry, are a hygiene threat when aerobically decomposed. Therefore, their management is crucial for public health. In this direction, anaerobic digestion (AD) systems may be the solution by transforming waste into energy, which may decrease the environmental impact. However, their efficacy should be carefully examined. In this innovative study, we evaluated the physicochemical and microbial characteristics of liquid digestate (LD) retrieved from organic animal wastes in northern Greece using nanofiltration. Using treatment technologies, including physical (solid–liquid separation, microfiltration, and nanofiltration) and biological (anaerobic digestion), heavy metals and microbial (i.e., Salmonella spp., Escherichia coli, and Enterococcus faecalis) concentrations were reduced and nutrients were recovered. This work sets the basis for the efficient management of liquid digestate. Our method may enable the use of treated liquid digestate for unlimited irrigation water and other industrial applications of water. Apart from the sanitation process, the recovery of nutrients for soil fertilization seems to be a more sustainable way for future agricultural practices.

Among key issues in municipal wastewater treatment plants (MWTP) is the existence of pathogenic bacteria in the discarded effluents. Conventional disinfectants (ozone, UV irradiation, chlorine) have been insufficient in providing safe water due to the development of undesirable and noxious by-products. TiO2 comprises an attractive alternative to conventional methods because of its versatility and recently explored biocidal efficiency. As a result, within the framework of this study, chemically modified, visible active nanocrystalline TiO2 powders (N-TiO2, N,S-TiO2, and Ag@N-TiO2) were prepared via a low-cost, feasible sol-gel method for the treatment of real municipal wastewater effluents. Wastewater samples were acquired from the outlet of the treatment of Antiparos (Cyclades, Greece) MWTP during the summer period in which a great number of seasonal habitants and tourists usually visit the island, resulting in at least a doubling of the population. All synthesized powders were thoroughly characterized using various morphological and spectroscopic techniques, such as FE-SEM, XRD, micro-Raman, FTIR, DLS, UV-DRS, and XPS. Photocatalytic evaluation experiments were initially conducted towards Rhodamine B degradation under visible light irradiation. Among all studied powders, Ag@N-TiO2 indicated the highest efficiency, reaching total degradation (100%) of RhB within 240 min due to its smaller crystallite size (1.80 nm), enhanced surface area (81 m2g−1), and reduced energy band gap (Eg = 2.79 eV). The effect of the produced powders on the disinfection as assessed in terms of fecal indicator microorganisms (E. coli and total coliforms) inactivation was also examined in a semi-pilot scale-up photocatalytic reactor. Ag@N-TiO2 nanopowder was also found substantially more active for both groups of bacteria, leading to complete inactivation in less than 35 min, probably due to the higher production of H2O2/•OH, as emerged from the photocatalytic mechanism study. In addition, Ag@N-TiO2 nanoparticles demonstrated excellent photocatalytic and disinfection stability even after five subsequent recycling trials (8.34% activity loss and complete inactivation, respectively). The results of the present study demonstrate the feasibility for Ag@N-TiO2 to be utilized as a viable, eco-friendly approach for the photocatalytic pathogenic bacteria inactivation as an alternative disinfection approach for municipal wastewater treatment plant effluents with intense seasonal fluctuations in volume.

The remarkable optoelectronic characteristics of hybrid metal halide perovskite semiconductors, such as high defect tolerance, extended carrier lifetime and diffusion length, and adjustable optical bandgap, have garnered much interest in the last decade. Therefore, this paper considers the experimental and mathematical modeling of triple-cation perovskite solar cells (PSCs) with two different device structures. It is challenging to construct a reliable mathematical model of triple-cation perovskite solar cells based on the three-diode model due to its complex nature. This is related to the perovskite materials' dynamics, nonlinearity, and sensitivity. This paper proposes a novel method incorporating a recent metaheuristic algorithm named COOT optimizer to estimate the optimal parameters of the three-diode equivalent circuit of triple-cation perovskite solar cells. The key idea is to use the swarm intelligence-based COOT to optimally achieve the PV panel's optimal parameters. The identification method benefits from the exploration and exploitation abilities of the COOT algorithm to obtain its parameters effortlessly and precisely. Two experiments are conducted in this work; the first is measured I–V datasets for a triple-cation perovskite (TC-per) solar cell at standard conditions. The second consists of the measured I–V datasets for a triple-cation modified perovskite (TCM-per) perovskite solar cell. During the optimization process, the nine unknown parameters of the three-diode model (TDM) are used as decision variables. The objective function to be minimized is the root-mean-square error (RMSE) between the measured and estimated data. An extensive comparative study is presented with other optimizers of the whale optimization algorithm (WOA), seagull optimization algorithm (SOA), sine cosine algorithm (SCA), ant lion optimization (ALO), and dragonfly algorithm (DA). Furthermore, statistical analysis of ANOVA is performed. The obtained results confirm the superiority of the proposed method in constructing a reliable model of the three-diode model of PSCs as it provides the least RMSE between the measured and estimated characteristics of 1.61E−05 in the first dataset. In contrast, the poorest algorithm (SCA) provides 1.03E−04. Similarly, in the second dataset of experiments, COOT achieves the least RMSE of 1.82E−05; meanwhile, the largest RMSE of 1.03E−04 using ALO. Based on the strong correlation between experimental and theoretical results using the COOT algorithm, we proposed a theoretical way (close to reality) to get the photovoltaic parameters of ideality factor and parasitic resistances in perovskite solar cell devices.

We investigate super-hydrophilic TiO _2 (titania) films for concentrated solar-thermal power applications. Reactive magnetron sputtering has been used to deposit 8 to 12 nm thick titania thin films onto borosilicate microscope glass slides, low-Fe extra-clear architectural glass, or Si(100) wafers with a 500 nm thick thermal SiO _2 layer. The effects of deposition temperature and O _2 fraction of the O _2 /Ar working gas were investigated. We demonstrate the importance of the O _2 fraction for obtaining optically transparent, super-hydrophilic (contact angle below 1°) thin films. In particular, we show that as the O _2 fraction increases, contact angle decreases, obtaining super-hydrophilic titania thin films at deposition temperatures as low as 120 °C. Our work enables to develop low thermal budget cost-efficient industrial synthesis processes, paving the way for commercial applications.