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The higher the polarity or the hydrogen bond donor ability of the solvent, the more easily COFs crystallize, and the higher the COF crystallization, the higher the photocatalytic H2 evolution.

We successfully synthesized a series of Y, C, O tridoped g-C3N4 photocatalysts using a simple one-step thermal polymerization method as a bifunctional photocatalyst for H2 production and pollutant degradation under visible-light irradiation.

A sulfide oxidation tuning approach in BDTT is reported for constructing a series of dual acceptor1-2 (A1–A2)-type copolymers. PBDTTS-1SO achieved an outstanding HER, demonstrating that the immense potential of the A1-A2-type polymer photocatalysts.

This study investigated bioethanol production from rice straw (RS) and sugarcane bagasse (SCB) which containing 72.8 and 73.2% holocellulose, 56.8 and 58.6% α-cellulose, and 14.9 and 25.1% lignin for RS and SCB, respectively. To eliminate the lignin content, different pretreatment conditions, such as hot water, dilute acid, and acid-alkali, were designed. Acid-alkali was characterized as the best pretreatment for removing ∼79 and 70% of lignin, α-cellulose increased 91.4 and 91%, and holocellulose reached 90.8 and 90% for RS and SCB, respectively. The results revealed that acid-alkali was highly efficient than other pretreatment used for both RS and SCB. After enzymatic hydrolysis of acid-alkali-treated RS and SCB with cellulase, glucose concentrations reached 45 and 42 g/l, respectively. Pichia occidentalis AS.2 was isolated and identified based on 18S rRNA sequencing as a bioethanol producer. Maximization of bioethanol production by P. occidentalis AS.2 using the resulting glucose as a carbon source from RS and SCB was studied using an experimental design. The pH, incubation period, and inoculum size were optimized using Box-Behnken designs (BBD), the final conditions for bioethanol production used 100 g/l acid-alkali-treated fibers, 10 ml cellulase enzyme at 50°C for 5 days at 75 rpm for enzymatic hydrolysis. After time consumed and adjusting the pH to 6, the mixture was inoculated with 2.5% P. occidentalis AS.2 and incubated at 35°C for 24 h at 200 rpm to increase the bioethanol yield by 1.39-fold to 23.7 and 21.4 g/l compared to initial production (17 and 15.3 g/l) between RS and SCB, respectively.

Organic semiconducting polymers exhibited promising photocatalytic behavior for hydrogen (H2) evolution, especially when prepared in the form of polymer dots (Pdots). However, the Pdot structures were formed using common nonconjugated amphiphilic polymers, which have a negative effect on charge transfer between photocatalysts and reactants and are unable to participate in the photocatalytic reaction. This study presents a new strategy for constructing binary Pdot photocatalysts by replacing the nonconjugated amphiphilic polymer typically employed in the preparation of polymer nanoparticles (Pdots) with a low-molecular-weight conjugated polyelectrolyte. The as-prepared polyelectrolyte/hydrophobic polymer-based binary Pdots truly enhance the electron transfer between the Pt cocatalyst and the polymer photocatalyst with good water dispersibility. Moreover, unlike the nonconjugated amphiphilic polymer, the photophysics and mechanism of this photocatalytic system through time-correlated single-photon counting (TCSPC) and transient absorption (TA) measurements confirmed the Forster resonance energy transfer (FRET) between the polyelectrolyte as a donor and the hydrophobic polymer as an acceptor. As a result, the designated binary Pdot photocatalysts significantly enhanced the hydrogen evolution rate (HER) of 43 900 μmol g-1 h-1 (63.5 μmol h-1, at 420 nm) for PTTPA/PFTBTA Pdots under visible-light irradiation.

The need for novel and active antibiotics specially from actinomycetes is essential due to new and drug-resistant pathogens. In this study, 87 actinomycetes were isolated, and 18 strains among them characterized as thermophilic actinomycetes. Further fractionation and preliminary antibacterial activities indicated that one strain, coded as MI-S.24-3, showed good antibacterial activity. Based on the phenotypic, genomic, phylogenetic, and biochemical analyses, MI-S.24-3 was identified as Streptomyces werraensis. Results demonstrated that the ethyl acetate active fraction showed maximum antibacterial activity against Staphylococcus aureus and Escherichia coli with MIC (12.7 ± 0.1 and 18.3 ± 0.2 mg/mL), and MBC (96.5 ± 1.4 and 91.5 ± 0.7 mg/mL), respectively, with determination of time kill kinetics assay. The active fraction showed moderate-to-weak cytotoxic effects against human lung carcinoma (A549 cells), breast cancer cell line (MCF-7), and human cervical carcinoma (HELA cells) with a IC50 of (23.8 ± 1.2, 54 ± 1.8, 96.4 ± 3.2 μg/mL, respectively). Active components were characterised by different chemically volatile, ester, and lactone compounds, determined by GC–MS coupled with daughter ions of (GC–MS/MS). Notably, erucic acid and reynosin identified compounds are rare metabolites produced by Streptomyces werraensis. Our findings demonstrated that the MI-S.24-3 strain could be a potential source for active compounds of biomedical and pharmaceutical interest.

In this paper we describe three indacenodithiophene-based conjugated polymers (PITIC-Ph, PITIC-Th, and PITIC-ThF) that we tested as third components for PM6:Y6-based ternary organic photovoltaics (OPVs) to provide high-power conversion efficiencies (PCEs) and long-term thermal stabilities. Among them, the incorporation of PITIC-Ph enhanced the charge dissociation and prohibited the bimolecular (trap-assisted) recombination of the PM6:Y6 blend. Compared with the pre-optimized OPV device, the PCEs of the PITIC-Ph-doped devices improved from 15.0 ± 0.37 to 17.0 ± 0.35% under AM 1.5 G (100 mW cm−2) irradiation. More critically, studies of the thermal stability revealed another phenomenon: embedding PITIC-Ph decreased the degree of thermally driven phase segregation of the PM6:Y6 blend film. The respective OPVs exhibited outstanding thermal stability under stress at 150 °C within a glove box, with the PCE of the PITIC-Ph-doped device remaining high (at 16.4%) after annealing for 560 h.

Photoactive conjugated microporous polymers (CMPs) are emerging as porous materials capable of mediating the photocatalytic evolution of H2 from water. In this study, we synthesized three pyrene-based CMPs (Py–F-CMP, Py–TPA-CMP, Py–TPE-CMP) through Sonogashira–Hagihara cross-couplings of 1,3,6,8-tetraethynylpyrene (Py–T, as a common monomer building block) with 2,7-dibromo-9H-fluorene (F–Br2), tris(4-bromophenyl)amine (TPA–Br3), and 1,1,2,2-tetrakis(4-bromophenyl)ethene (TPE–Br4), respectively, in the presence of Pd(PPh3)4 in DMF/Et3N. We then characterized the chemical structures, crystallinities, thermal stabilities, surface morphologies, and porosities of these three new CMPs. Brunauer–Emmett–Teller (BET) analyses and tests of photocatalytic H2 production revealed that Py–TPA-CMP displayed the highest BET surface area (454 m2 g−1), highest total pore volume (0.28 cm3 g−1), highest H2 evolution rate (19 200 μmol h−1 g−1), and highest apparent quantum yield (15.3%) when compared with those of Py–F-CMP, Py–TPE-CMP, and other organic porous materials.

The organic semiconducting polymer dots (Pdot) or nanoparticles exhibited a promising efficiency as photocatalyst for hydrogen production. This study reported a new Pdot-based photocatalyst constructed in the form of Donor-Acceptor-Metal cocatalyst (D-A-Mcat). These D-A-Mcat Pdots systems consisting of fluorene (F) as the donor, thienyl-benzo-dithiophene-dione (TBDD) as the acceptor and [Ir (TPy)2 (acac)] as the metal complex, and their structural, thermal, electrochemical and photophysical properties were systematically demonstrated for the first time. Introducing the cyclometalated iridium (III) complex comonomer into the polymer chain resulting in PFTBDD-IrTPy Pdots showed enhancement of the hydrogen evolution rates, which is over 20-times higher than those of pure polymer (PFTBDD Pdots) under otherwise identical conditions. In addition, the optical and electrical measurements indicated that the cyclometalated iridium (III) part have an important function for inhibiting the charge recombination of the PFTBDD-IrTPy Pdots during the photocatalytic reaction. The result strongly implies that inserted catalytic amount of Ir(III)-complex into the D-A polymers is beneficial for the enhancement of photocatalytic hydrogen evolution, which can inspire further optimization and greater molecular design strategies at a low-cost are highly desirable for the development of high-performance in photocatalysis.

This work reports the preparation of Na-doped ZnO (Na-ZnO) as a promising photocatalyst under sunlight through a very simple precipitation method. The crystal and electronic structures of the prepared Na-ZnO were characterized by experimental techniques and Density Functional Theory (DFT) calculations. Where the DFT calculations revealed that the effect of Na-doping on the ZnO electronic structure is consistent with the experimental observations and the bandgap value found to be decreasing. Under direct sunlight, the as-prepared Na-ZnO decolorized more than 99.5% of the methylene blue dye (MB) after 1.5 h and led to mineralization of 98.3% of it after 3 h. While pure ZnO decolorized only 35% of MB dye at the same conditions. The prepared Na-ZnO has a promising photocatalytic activity at different pH's and high photostability reaching to 7 recycle with the same efficiency. Finally, the primary active species produced during the photocatalytic reaction were determined and the photocatalytic mechanism was elucidated.

In this study, we used effective and one-pot Heck coupling reactions under moderate reaction conditions to construct two new hybrid porous polymers (named OVS-P-TPA and OVS-P-F HPPs) with high yield, based on silsesquioxane cage nanoparticles through the reaction of octavinylsilsesquioxane (OVS) with different brominated pyrene (P-Br4), triphenylamine (TPA-Br3), and fluorene (F-Br2) as co-monomer units. The successful syntheses of both OVS-HPPs were tested using various instruments, such as X-ray photoelectron (XPS), solid-state 13C NMR, and Fourier transform infrared spectroscopy (FTIR) analyses. All spectroscopic data confirmed the successful incorporation and linkage of P, TPA, and F units into the POSS cage in order to form porous OVS-HPP materials. In addition, the thermogravimetric analysis (TGA) and N2 adsorption analyses revealed the thermal stabilities of OVS-P-F HPP (Td10 = 444 °C; char yield: 79 wt%), with a significant specific surface area of 375 m2 g–1 and a large pore volume of 0.69 cm3 g–1. According to electrochemical three-electrode performance, the OVS-P-F HPP precursor displayed superior capacitances of 292 F g−1 with a capacity retention of 99.8% compared to OVS-P-TPA HPP material. Interestingly, the OVS-P-TPA HPP showed a promising HER value of 701.9 µmol g−1 h−1, which is more than 12 times higher than that of OVS-P-F HPP (56.6 µmol g−1 h−1), based on photocatalytic experimental results.

We have designed and synthesized a series of conjugated polymers with fluorene or carbazole and phenylphosphine oxide derivatives as polymer photocatalysts for visible-light-driven hydrogen evolution. The optimized polymer photocatalyst PCzBPO provided an excellent hydrogen evolution rate (HER) over two-orders of magnitude greater than its counterparts under otherwise identical conditions due to their unique combined effects of the introduced strong electron-withdrawing group, planar structure, extended conjugation length, and efficient charge transfer between donor/acceptor. Moreover, the PCzBPO exhibited an excellent HER with a record high apparent quantum yields (AQYs) of 14.92 ± 0.10% at 420 nm and 14.88 ± 0.08% at 460 nm with the residual palladium content and the absence of Pt cocatalysts. We believe that this systematic study on phenylphosphine oxide-containing polymers as ideal polymer photocatalysts could inspire further optimization and greater molecular design strategies in the development of high-performance photocatalysts to give a high impact in this field.

In this work, we present the first study on organic semiconductors as a photoconductive terahertz spatial light modulator (THz SLM), to the best of the authors’ knowledge. The characterization includes modulation depth (MD) created by the photocarriers within the material and the measurement of carrier lifetime, relating to the operation speed of the material. We observed 16.50% of MD, and the carrier lifetime was measured to be 4.527 ns. As the carrier lifetime is similar to gallium arsenide (GaAs), we compare both and discover an order of magnitude enhancement in MD. This report shows that organic semiconductors can serve as a promising high-speed THz SLM for real-time terahertz imaging.

Searching an efficient and robust photocatalyst is important in converting solar energy into chemical energy for clean and renewable fuels. Thiophene and fluorene have been widely used in this field. However, no studies exist on understanding the effect of increasing the number of fused thiophene and fluorene rings. Herein, we demonstrated a series of polymer photocatalysts based on fused rings with fluorene (F) and indenofluorene (IF) units and fused-thiophene rings (thiophene (T), thienothiophene (2T), and dithienothiophene (3T)) in different combinations, denoted as PFnT and PIFnT, where n is the number of fused thiophene rings. We show that the increased number of fused rings on fluorene or thiophene units is important for photocatalytic performance. Particularly, without adding the noble Pt cocatalysts, our PF3T presented an excellent efficiency with a hydrogen evolution rate (HER) of 1095 µmol h−1 g−1 (λ > 420 nm). We show that the photocatalysts are robust, that is, PF2T could be used for over 70 hours. More importantly, even when we stored PF2T in a water/methanol/TEA solution for 20 days, its photocatalytic performance remained constant. This contribution documents the first systematic study on the construction of efficient and robust polymer photocatalysts, allowing the researcher to potentially target the number of fused rings on polymers and provides an important impact in this field.

Conjugated polymer dots (Pdots) based on a series of BDT-based polymers with varied biaxially extended side-chain conjugations were prepared and employed for photocatalytic hydrogen production under visible light irradiation from aqueous solutions. The BDT-based polymers consisted of a dithiophedifluorobenzo[c][1,2,5]thiadiazole (DFBT) moiety as the acceptor unit and a BDT unit with different biaxially extended side-chains, including a alkyl-monothienyl group (T), a linear alkyl-dithiophene (2 T) group, a branched alkyl-terthiophene (3 T) group, and a fused alkyl-benzotrithiophene (B3T) group. The as-prepared Pdots based on these four polymers (PBDT-T, PBDT-2T, PBDT-3T, and PBDT-B3T) showed varied photophysical and electrochemical properties along with distinctive photocatalytic activity and long-term stability. Among them, the PBDT-B3T Pdots were showed to deliver a high photocatalytic efficiency of 14.1 mmol g-1 h-1 and a superior photocatalytic stability over 375 h in the presence of Pt as cocatalyst and ascorbic acid as sacrificial electron donors. Our results revealed that varying the structures of the biaxially extended side-chains endows a great flexibility in the photocatalytic activity of the polymers and the biaxially-extended conjugated side-chains can be a promising design strategy for the conjugated polymer to enhance the photocatalytic activity and stability.

Utilization of g-C3N4 as a single photocatalyst material without combination with other semiconductor remains challenging. Herein, we report a facile green method for synthesizing a metal free modified g-C3N4 photocatalyst. The modification process combines four different strategies in a one-pot thermal reaction: non-metal doping, porosity generation, functionalization with amino groups, and thermal oxidation etching. The as-prepared amino-functionalized ultrathin nanoporous boron-doped g-C3N4 exhibited a high specific surface area of 143.2 m2 g−1 which resulted in abundant adsorption sites for CO2 and water molecules. The surface amino groups act as Lewis basic sites to adsorb acidic CO2 molecules, which can also serve as active sites to facilitate hydrogen generation. Besides, the simultaneous use of ammonium chloride as a dynamic gas bubble template along with thermal oxidation etching efficiently boosts the delamination of the g-C3N4 layers to produce ultrathin sheets; this leads to stronger light–matter interactions and efficient charge generation. Consequently, the newly modified g-C3N4 achieved selective gas-phase CO2 reduction into CO with a production yield of 21.95 µmol g−1, in the absence of any cocatalyst. Moreover, a high hydrogen generation rate of 3800 µmol g-1h−1 and prominent apparent quantum yield of 10.6% were recorded. This work opens up a new avenue to explore different rational modifications of g-C3N4 nanosheets for the efficient production of clean energy.

A library of donor-acceptor system consisting of cyclopentadithiophene-based polymer photocatalysts have been designed and synthesized. Among all photocatalysts, the active PCPDTBSO achieved hydrogen evolution rates of 24.6 mmol h–1 g–1 with apparent quantum yields of 8.7 % at 500 nm. More importantly, combined the results of photocatalytic efficiency, apparent quantum yield, the time-resolved fluorescence decay spectra, the steady-state photoluminescence spectra, and the transient absorption spectroscopy, and the oxidation potentials of sacrificial donors and protons reduction potentials in different pH values, we confirmed the concept that ascorbic acid is a suitable sacrificial donor for narrow bandgap polymers and triethylamine is a suitable sacrificial donor for wide bandgap polymers owing to the existence of the optimal thermodynamic driving force. We believed this study would be advantageous for the selection of photocatalysts and sacrificial donors for hydrogen production.

Conjugated microporous polymers (CMPs) have emerged in recent years as prospective materials for photocatalytic hydrogen production. The most common synthesis method for triazine is ionothermal synthesis at high temperatures (>350 °C), which also requires a large amount of ZnCl2, in which CF3SO3H-catalyzed method was invented to synthesize triphenyl triazine at room temperature. Herein, we reported the synthesis and characterization of two triazine-based conjugated micropores polymers photocatalysts at low temperature via polymerization of triphenyl triazine (TPT) with TPT and pyrene (Py). The TPT-based CMPs show excellent photocatalytic performance and a hydrogen evolution rate of 108.1 and 116.5 µmol h−1 under visible light for Py-TPT-CMP and TPT-TPT-CMP, respectively, but with low photocatalytic stability. In general, organic polymers add a small amount of platinum to efficiently produce H2 with high photocatalyst stability. To provide a new opportunity to overcome the low stability, a sulfur doping method using readily available sulfur (S8) has been proposed which was used here for the first time to achieve a highly photocatalyst stability development without the use of noble metals. The as-synthesized polymers after sulfur doped exhibit an enhanced photocatalytic stability which can keep the hydrogen production for a long period of time without loss in the photocatalytic efficiency. Furthermore, our triazine-based CMP materials have interest apparent quantum yield (AQY) values particularly for Py-TPT-CMP and TPT-TPT-CMP which exhibit AQY of 41.9 and 32.38%, respectively at 420 nm, these values are compatible with the highest AQY of organic photocatalysts up to date. This study makes a significant contribution forward for photocatalysis with polymers because it provides excellent HERs and AQYs for the sulfur-doped triazine-based CMPs with high thermal, chemical, and photo stabilities. As well as, this work could give researchers in the field a different opinion on the effect of sulfur-doping.

This research aims to use modified ZnO nanoparticles to enhance the removal rate of the methylene blue (MB) dye. ZnO nanoparticles are modified by coating their surface with Congo red (CR) dye, henceforth referred to as ZnO/CR. This process is used to produce a Lewis acid on the surface of ZnO to attract any Lewis base such as a MB dye (MB+). Therefore, the stability of ZnO/CR improved, and it resists the change in pH value (from 3 to 9). Several analysis techniques such as scanning electron microscopy, X-ray diffraction, FTIR, and BET method were used to characterize ZnO/CR. Nonlinear and linear regressions of pseudo first-order, pseudo second-order, and Elovich models were used to calculate the kinetic parameters of the adsorption process. The best-fit kinetic equation was investigated using three functions of error analysis: the sum of the squares of the errors, chi-square analysis, and the coefficient of determination. The intraparticle diffusion equation was used to study the diffusion process. The adsorption process of the MB followed the Langmuir model with a maximum capacity (qm) value of 43.5 mg/g. This value is six times greater than the value calculated with pure ZnO. Thermodynamic parameters ΔS•, ΔH•, and ΔG• were investigated at four temperatures (10, 20, 30, and 40 °C). The uptake process of the MB occurs spontaneously following endothermic process and an increase in the system disorder. The rate of adsorption was controlled mainly by a Lewis acid–base interaction and H bonding. Furthermore, the removal of the MB by ZnO/CR powder worked well as a chemical and physical adsorption process.

Effective photocatalytic systems that are capable of converting solar energy into chemical fuels have recently attracted significant attention. Covalent organic polymers (COPs) have been explored as promising photocatalysts for visible-light-driven hydrogen evolution from water. Herein, a series of triptycene (TP)-based discontinuously conjugated COP photocatalysts are described for the first-time using TP with monothiophene (MT), trithiophene (TT), dithiophene benzothiadiazole (DTBT), and diphenyl benzothiadiazole (DPBT), denoted as MT-TP, TT-TP, DTBT-TP, and DPBT-TP, respectively. Difference photophysical, morphological, and photocatalytic properties can be tuned by introducing different types of linkers of the TP-based COPs. DPBT-TP shows a significant enhancement of the hydrogen evolution rate (HER) in comparison to those using other polymer photocatalysts at identical conditions. The transmission electron microscopy/scanning electron microscopy data show that the tube-like polymer photocatalysts afford higher HERs than those observed with the particle-like polymer photocatalysts. This report describes the first demonstration that the polymer photocatalysts constructed by the disconuiously conjugated system (conjugation length: less than 5 aromatic rings) is sufficient for an efficient visible-light-driven hydrogen evolution. It provides an alternative material design strategy for polymer photocatalysts to achieve efficient visible light hydrogen evolution.

Given the photocatalytic properties of semiconducting polymers and carbon quantum dots (CQDs), we report a new structure for a metal-free photocatalytic system with a promising efficiency for hydrogen production through the combination of an organic semiconducting polymer (PFTBTA) and N-doped carbon quantum dots (NCQDs) covered by PS-PEGCOOH to produce heterostructured photocatalysts in the form of polymer dots (Pdots). This design could provide strong interactions between the two materials owing to the space confinement effect in nanometer-sized Pdots. Small particle size NCQDs are easy to insert inside the Pdot, which leads to an increase in the stability of the Pdot structure and enhances the hydrogen evolution rate by approximately 5-fold over that of pure PFTBTA Pdots. The photophysics and the mechanism behind the catalytic activity of our design are investigated by transient absorption measurement, demonstrating the role of NCQDs to enhance the charge separation and the photocatalytic efficiency of the PFTBTA Pdot.

By mimicking nature photosynthesis, a library of cycloplatinated polymer dots (Pdots) and pristine Pdots are presented and investigated the importance of selecting acceptor comonomers. A clear design strategy for the selection of acceptor comonomers of Pdots to achieve environmental-friendly, high efficiency, and long stability of photocatalytic reaction can be understood. The active PFTBTA-PtPy Pdots provide the excellent hydrogen evolution rates up to 7.34 ± 0.82 mmol h–1 g–1 under a methanol-free solution and visible-light-driven system. MTT assay experiments confirm the use of the cycloplatinated Pdots as photocatalysts can minimize the toxicity, relative to the conventional approach that directly adding Pt into a solution system. Furthermore, the Pdots can be reactivated for hydrogen generation by the recycling process. The result proves that the use of cycloplatinated Pdots can not only enhance the HER efficiency and stability but also reduce the toxicity.

Aim: The present study aimed to develop cost-effective, eco-friendly marine Streptomyces cyaneus strain Alex-SK121 mediated synthesis of silver nanoparticles (AgNPs) with