The production of aromatics, specifically benzene, toluene and xylenes (BTX), from bio-derived feedstock such as ethanol and furfural can be achieved by zeolite catalysts. However, the formation of coke strongly limits this reaction leading to catalyst deactivation. In-depth understanding of the relationship between the catalyst characteristics and the mechanism of carbon deposit is needed to improve potential applicability of this novel approach for BTX production. Evaluation of the catalytic activity of beta and ZSM-5 zeolites in the aromatization of ethanol and furfural, coupled with the characterization of the spent catalysts, gave important insights on the structure and features that are required to increase the aromatics formation. With these investigations it was possible to determine the location of the catalytic sites that are active in the aromatization reaction, defining at the same time the mechanism of deactivation by coke formation. These findings give important advances for the future design of efficient catalysts for the aromatics production.

A bifunctional linker for robust and straightforward functionalization of carbon-based nanomaterials, featuring an azido group at one end and a diazonium group at the other, is synthesized and used to introduce azido groups on the sidewalls of (6,5)-single-wall carbon nanotubes. The versatility of the azido groups as reactive handles is demonstrated by further functionalization with 6-carboxyfluorescein and oligonucleotides through copper-free strain-promoted azide-alkyne cycloaddition, ideal for biological applications. UV melting profiles and atomic force microscopy (AFM) images of mixtures of nanotubes functionalized with complementary oligonucleotide strands are consistent with hybridization-controlled bundling-debundling equilibria.

Water-in-salt electrolytes coupled with redox species (RC-WiSEs) can be promising candidates for 2D Ti3C2Tx MXene supercapacitors due to their expanded electrochemical stability window (ESW) and enhanced diffusion-controlled contributions. Herein, the incorporation of RC-ZnCl2 WiSE into a Ti3C2Tx MXene supercapacitor enables a wide ESW of 1.6 V, along with high capacity and ultrastability. The Ti3C2Tx MXene supercapacitor delivers a maximum energy density of 36.7 Wh kg-1 and a power density of 3065 W kg-1. Notably, the device retains approximately 80% of its capacity even after 100,000 continuous galvanostatic charge–discharge cycles and also maintains stable capacitive performance over a broad temperature range from -5 °C to 45 °C. A thorough in situ Raman and UV-Vis spectroelectrochemical investigation, combined with electrochemical analysis, reveals that redox species directly regulate interfacial chemistry, thereby enhancing the capacity and stability of the electrode. This work demonstrates the effectiveness of RC-WiSE systems and encourages their use to enhance the charge storage capacity and cycling stability of MXene-based systems.

The integration of biologically inspired materials into photonic device fabrication offers a promising route toward sustainable and biocompatible alternative to conventional in inorganic or petroleum based synthetic materials used in optoelectronic systems. In this work, we present a biosynthetic approach for waveguide fabrication utilizing a biomimetic - de novo designed elastin-like polypeptide (ELP) formulated into an all-water-based photoresist compatible with two-photon polymerization (2PP). The ELP was genetically engineered and recombinantly produced in microbes for enhanced molecular stability, a critical feature for withstanding both localized and bulk temperature increases that occur during high-intensity laser exposure during printing. The resulting ELP formulation supported direct writing of waveguide architecture without the need for organic solvents, harsh processing steps, or post-functionalization. This aqueous resist formulation exhibits high stability during printing and retains its structural integrity upon curing, making it a promising candidate for environmentally friendly, soft-material photonics. This work establishes a foundation for using biosynthetic polypeptides in the fabrication of functional photonic elements and demonstrates a step toward greener, protein-based optoelectronic manufacturing technologies.

Electrocopolymerization of different monomers is a useful approach for developing materials with tailored electrochromic properties and expanded color palettes. We report electrocopolymerization of two distinct monomers - zinc(ii) tetrakis(4-aminophenyl)porphyrin (ZnTAPP) and 3,4-ethylenedioxythiophene (EDOT) on an FTO-coated glass substrate. Our copolymer, poly(ZnTAPP-EDOT), exhibits a reversible color change from orange-brown to olive-green, with optical contrasts of 25% and 31% in the visible and beginning of the near-IR (bNIR) regions, respectively. It also demonstrates high coloration efficiencies of 434 cm2 C-1 (visible region) and 181 cm2 C-1 (bNIR region). Furthermore, poly(ZnTAPP-EDOT) retains 88%of its electrochromic performance in the visible and 82% in the bNIR regions after 200 redox cycles, along with a fast switching response and strong optical memory under open-circuit conditions. Our time-dependent density functional theory (TDDFT) calculations reveal that the increasing EDOT units between ZnTAPP moieties promote a systematic redshift in absorption peaks and enhance oscillator strengths, attributed to extended pi-delocalization facilitated by the added EDOT linkages, corroborating experimental UV-vis data. Our results suggest that the electrocopolymerization of suitable porphyrins with selective monomers can produce electrochromic materials with tunable optical properties, high efficiency, and stability, making them well-suited for use in electrochromic devices.

Three copper(II) complexes with variously substituted amine-bisphenolates (H2L1, H2L2 and H2L3) have been prepared. Variation in the composition and structure of the free ligands resulted in the formation of three structurally distinct copper(II) complexes: dinuclear 1, mononuclear 2 and trinuclear 3. Various physical techniques were used to characterise the complexes, including single-crystal X-ray analysis and variable-temperature magnetic susceptibility measurements (5-297 K). The compounds were evaluated for their in vitro anti-proliferative effects against three human cancer cell lines (ovarian A2780 and A2780R, breast MCF7) and normal HaCaT cells. The results showed that both the free ligands and the complexes exhibit strong-to-moderate cytotoxicity. 2 and 3 are significantly more effective against A2780, A2780R and MCF7 cells than the metallodrug cisplatin. The cytotoxicity of complexes 1-3 is bound to the cytotoxicity of the free ligands and remains almost unchanged over 24, 48 and 72 h. The copper accumulation in A2780 cells was studied by ICP-MS over 2-72 h of co-incubation of 1-3. Complex 1 caused the highest uptake of copper into A2780 cells, reaching up to 100 times higher Cu concentration compared to untreated cells, while 2 and 3 showed only ca 5-10-fold increase of Cu uptake in A2780 cells. No apparent signs of hydrolysis of 1-3 in a MeOH/water mixture were observed in mass spectrometry experiments even after 72 h of standing at laboratory temperature. The mass spectrometry-based interaction studies of 1-3 with L-cysteine (Cys) and reduced glutathione (GSH) did not show direct evidence of the interaction product formation. Only the signals, corresponding to the free ligands were identified in mass spectra after 24 h and 72 h of incubation.

Photosynthetic microrganisms, including cyanobacteria, can be interfaced with electrodes in biophotovoltaic devices (BPVs) for solar energy conversion. Effective BPV electrodes need to be conductive, transparent, flexible, biocompatible and environmentally friendly, while also being cost-effective, abundant in material and lightweight. The utilization of electrically conducting polymers (CPs), particularly poly(3,4-ethylenedioxythiophene) (PEDOT) fabricated by an atmospheric pressure vapor phase polymerization (AP-VPP) technique, is a promising avenue for BPV applications. However, challenges remain in optimising their performance as CPs are dynamic optoelectronic materials, and their interaction with photosynthetic biocatalysts under a range of conditions has not been explored thoroughly. Here we show that AP-VPP-PEDOT electrodes hold promise for interfacing with cyanobacteria in BPVs to generate green electricity under red and blue light and moderate applied potentials with exogenous electron mediators. The highest non-mediated photocurrent achieved was 0.48 µA cm−2, with a two-layer PEDOT electrode at 0.5 V applied potential and blue light. The highest mediated photocurrent achieved was 2.73 µA cm−2, with a one-layer PEDOT electrode at 0.3 V applied potential and blue light and the exogenous electron mediator 2,6-dichloro-1,4-benzoquinone (DCBQ). The proposed approach to fabricating PEDOT electrodes offers a new pathway for developing sustainable electrodes for BPVs and pinpoints strategies for future optimisation for achieving high-performance outcomes.

The extent of nanoplastic pollution has raised severe environmental and health concerns. While the means for microplastic detection are abundant, improved tools for nanoplastic detection are called-for. State- of-the-art microscopic techniques can detect nanoplastics down to tens of nanometers, however, only from very small sample sizes (typically ∼10 µl). In this work, we describe a method that enables sampling of 1 liter of seawater by the means of correlative Raman- and SEM-techniques. This is achieved by adapting common microplastic sample purification protocols (i.e. chemical digestion) to suit the nanoplastic study. In addition, we decorate a membrane filter with SERS-property to amplify the Raman signals. Together, the purification method combined with the use of the SERS-activated-membrane-filter enables identification and imaging of individual nanoplastic particles from significantly larger sample sizes than before. In the nanoscale the average recovery rate is 5 %. These results aim to provide useful tools for researchers in the fight against plastic pollution.

Abstract The electrochemical reduction of CO2 (ERCO2) to valuable chemicals such as acetic acid/acetate offers a promising route to revolutionize chemical production and enhance sustainability. Here, we report the hydrothermal preparation of an electrocatalyst consisting of copper/titanium dioxide/reduced graphene oxide (Cu‐TiO2/rGO) for ERCO2 in aqueous medium. The metal‐support (TiO2/rGO) was pre‐synthesized by combining an aqueous solution of TiO2 and GO in an autoclave at 150 °C for 20 h. Then TiO2/rGO was added to synthesized Cu colloid formed through the reduction of copper (II) nitrate trihydrate resulting in the formation of Cu‐TiO2/rGO. The Cu‐TiO2/rGO hybrid nanocomposite was fully characterized using spectroscopic and microscopic techniques. This study explored the versatility of the rotating ring‐disc electrode (RRDE) as an in situ electroanalytical tool for the selective detection of products formed during ERCO2. The well‐designed hybrid electrocatalyst, containing Cu0/Cu+ active sites, facilitated the eight‐electron transfer for acetic acid (AA) formation at low potentials. AA formation was detected on the RRDE and validated by conventional NMR and HPLC techniques. This work highlights and expands the scope of selective hydrogenation of CO2 towards value‐added products.

Two-dimensional (2D)-Ti3C2Tx is a promising candidate for supercapacitors; however, it undergoes irreversible oxidation in aqueous acidic electrolytes at a higher anodic potential. Here, we enhance the supercapacitive performance of Ti3C2Tx in the potential range of 0-1 V by a suitable combination of intercalating molecules (for example, EmBF4 [1-ethyl-3-methylimidazolium] and BmBF4 [1-butyl-3-methylimidazolium] tetrafluoroborate) and redox electrolytes (for example, H2SO4 plus KI). Pristine Ti3C2Tx, Em -intercalated Ti3C2Tx (Ti3C2Tx-Em), and Bm-intercalated Ti3C2Tx (Ti3C2Tx- Bm) are utilized for supercapacitor applications and show low capacitance and poor stability in 1 M H2SO4. Interestingly, Ti3C2Tx, Ti3C2Tx-Em, and Ti3C2Tx-Bm supercapacitors exhibit improved performance in redox electrolyte. In particular, Ti3C2Tx- Em demonstrates gravimetric capacitance of 725 Fg-1 and >90% capacitance retention after 10,000 cycles. We attribute this high performance to (1) the higher interlayer spacing of Ti3C2Tx-ionic liquids and (2) effective interaction of the redox pair with the Ti3C2Tx- Em framework. Our findings suggest that incorporating anodic redox pairs into aqueous acidic electrolytes is a valuable strategy to improve the performance of Ti3C2Tx electrodes.

Fluorenones are suitable candidate for negolytes in flow batteries, as they demonstrate ability to store 2 electrons, and can achieve reversibility, solubility, and stability with appropriate molecular design. However, limitations persist such as the use of alkaline media, high redox potentials, and a limited scope for optimization. Herein, we report azoniafluorenones as a novel class of negolytes. They can be readily accessed in a highly modular fashion from inexpensive commercially available materials (e.g., boronic acids). Variations in the substitution patterns reveals the 3-substituted N-alkylated AZON3, which demonstrates excellent solubility at neutral pH (1.64 M) with two low reversible redox potentials (–0.31 V and –0.58 V vs Ag/AgCl). AZON3 exhibits high stability when evaluated at high concentration in a neutral supporting electrolyte (1 M in 3 M KCl), paired with BTMAP-Fc on the positive side. Capacity retentions of 99.95% and 99.91% per cycle (99.35% and 99.21% per day) are achieved when cycling with 1 and 2 electrons, respectively, coupled with high volumetric capacity of 46.4 Ah L-1 (87% of capacity utilization).

The extent of nanoplastic pollution has raised severe environmental and health concerns. While the means for microplastic detection are abundant, improved tools for nanoplastic detection are called-for. State- of-the-art microscopic techniques can detect nanoplastics down to tens of nanometers, however, only from very small sample sizes (typically ∼10 µl). In this work, we describe a method that enables sampling of 1 liter of seawater by the means of correlative Raman- and SEM-techniques. This is achieved by adapting common microplastic sample purification proto- cols (i.e. chemical digestion) to suit the nanoplastic study. In addition, we decorate a membrane filter with SERS-property to amplify the Raman signals. Together, the purification method combined with the use of the SERS-activated-membrane-filter enables identification and imaging of in- dividual nanoplastic particles from significantly larger sample sizes than before. These results aim to provide useful tools for researchers in the fight against plastic pollution.

A low-cost bimetallic bifunctional 5–5 wt% FeNi/H-Beta-300 catalyst was investigated in solventless hydrodeoxygenation of lignin-derived model compounds isoeugenol or dihydroeugenol in batch and continuous modes.

Food, feed and beverage processing brings tannins into contact with macromolecules, such as proteins and polysaccharides, leading to different chemical and physical interactions. The interactions of tannins with proteins are well known but less is known about the affinity of tannins to polysaccharides. We used bacterial cellulose from nata de coco as a model compound to investigate how tannins and cellulose interact by adsorption measurements using UPLC-DAD. We also explored how the structure of tannins influences these interactions. The model tannins included nine individual structurally different hydrolysable tannins (HTs) and eight well-defined proanthocyanidin (PA) fractions with different monomeric units, mean degree of polymerization and both A- and B-type linkages. Tannins were found to have both strong and weak interactions with bacterial cellulose, depending on the exact structure of the tannin. For HTs, the main structural features affecting the interactions were the structural flexibility of the HT molecule and the number of free galloyl groups. For PAs, prodelphinidins were found to have a higher affinity to cellulose than procyanidins. Similarly to HTs, the presence of free galloyl groups in galloylated PAs and the flexibility of the PA molecule led to a stronger interaction. Adsorption measurements by UPLC-DAD proved to be a sensitive and rapid tool to evaluate the affinity of tannins to cellulose.

Despite the array of applications for cationic polythiophenes (CPTs), there is still a need for structure-function guidelines and mechanistic understanding of their solution- and solid-state properties. This work presents a solution- and solid-state investigation of the effect of O-alkylation proximity on the hydrogen bonding (H-bonding) capabilities of alkoxy-CPTs, based on comparing an imidazolium alkoxy CPT with strong cation-pi, pi+ and positive charge-assisted hydrogen bonding (+CAHB) capabilities (PIMa), with two isothiouronium alkoxy CPTs with two-point +CAHB capabilities (PT1 & PT2), which have short and long alkoxy side chains, respectively. Our results show that a closer proximity of O-alkylation strengthens the +CAHB capabilities of PT1: in aqueous solutions, PT2 aggregates have a stronger interaction with cationic EPR spin probes than aggregates of PIMa and PT1, which in turn show a similar extent of repulsion towards the cationic spin probes. In solid-state, atomic force microscopy (AFM) shows that PIMa generates dendritic structures onto mica, with features of diffusion-limited aggregation (DLA), indicating strong interactions with the anionic substrate due to a high configurational entropy during spreading, regardless of being drop-casted from water or 1,4-dioxane-water (W-DI), despite the latter disturbing H-bonding due to selective solvation. PT1 is also capable of generating dendritic structures resembling ballistic aggregation (BA). However, this occurs only when casting from water, since W-DI generates island-like aggregates resembling attachment limited aggregation (ALA), which is the morphology generated by PT2 regardless of the solvent. Finally, spin-coated films of PIMa and PT1 show similar dispersivity of the surface free energy (SFE), which in turn is larger than that in PT2 films, which are also more affected when casted from W-DI, presenting much larger decreases of dispersivity. These results constitute a novel empirical structure-function guideline that could be useful for optimal design and/or processing of alkoxy CPTs. For example, dendritic patterns have recently gained attention since the colloidal droplet drying is related to engineering applications including inkjet printing, biosensing, and functional material design, while the SFE is relevant for opto- and bio-electronic applications of conjugated polyelectrolytes (CPEs). This information could also be useful when analyzing previous results obtained from alkoxy CPTs with different side chain lengths.

In the present work, solution-phase synthesis was employed to prepare two sets of catalysts with different transition metals as active sites. One set contained Au or Pd supported on TiO2 (Au-TiO2, Pd-TiO2), whereas the other set contained layered double hydroxides (NiFe-LDH and CuFe-LDH). The electrocatalytic performance of these composite materials was investigated by cyclic voltammetry (CV) using a model compound 4-nitrophenol (4-NP). Composite materials were characterized by various analytical techniques to gain insight into the catalysts active sites. The morphology and structure of the prepared samples were investigated by X-ray diffraction, attenuated total reflectance Fourier transform infrared, X-ray photoelectron spectroscopy, transmission scanning electron microscope, and field emission scanning electron microscope. Metal nanoparticles loading on TiO2 was measured by inductively coupled plasma - optical emission spectrometry. CV measurements were performed in acetonitrile solution containing 0.1 m tetrabutylammonium hexafluorophosphate (TBAPF(6)) and 1 mm 4-NP. Among all dioxides (Au-TiO2, Pd-TiO2) and hydroxides (NiFe-LDH and CuFe-LDH) studied, Pd-TiO2 shows the lowest onset potential (-0.32 V vs. Ag/AgCl) for the electrocatalytic reduction of 4-NP. This is the first comparative study of such materials for 4-NP electrocatalysis in aprotic solvent, thus demonstrating the suitability of dioxide and hydroxide based materials as electrocatalysts.

A non-benzenoid aromatic hydrocarbon azulene, naturally found in plants and mushrooms, is known for its derivatives applications in medicines. However, the processability of its chemically synthesized high-capacitance polymer is constrained by the sparingly soluble nature of its polymeric form. Oxidative chemical synthesis on a desirable substrate overcomes this difficulty. In this report, polyazulene (PAz) thin films are synthesized by vapor phase polymerization at atmospheric pressure using oxidants, such as CuCl2, CuBr2, FeCl3, and FeTOS. The effect of oxidants on morphologies of PAz films is studied using atomic force microscopy and microscope imaging. Each oxidant produced distinct microstructures in the films. The films synthesized using Cu(II) salts showed organized and knitted structures, whereas Fe(III) salts formed casted sheet-like disordered arrangements. The films synthesized using CuCl2 created uniform porous film assemblies. The pre-peak formations and their splitting observed in the cyclic voltammograms revealed phase segregations in the films. Oxidant-dependent structural and chemical differences such as charge carrier formation, doping levels, and polymer chain length in the PAz films are studied by using UV-Vis and FTIR spectroscopy. The results indicated that 240 and 180 mM are the optimum concentration of CuCl2 to produce high capacitance and well-organized single-and triple-layered PAz films, respectively.

The sterile conk caused by the infection of the basidiomycete Inonotus obliquus (Chaga) is an important source of bioactive compounds. However, its structure and biochemistry are only generally understood. Solid state 13 C NMR and FTIR spectroscopy have been utilized for the first time to investigate the sterile conk with non-invasive methods. The application of multivariate data analysis techniques and spectral distance algorithm to the obtained datasets showed clear distinction between the outer and inner layers of the sterile conk. Moreover, the sterile conk bark, compared to the inner layers, was spectroscopically more similar to wood tissues. The fungal tissue was proven to be concentrated below the bark. The similarity of the sterile conk inner layers to both decayed wood and hyphae of I. obliquus was shown by the multivariate data analysis of both spectra datasets. The spectroscopic data indicated lack of lignin degradation in the heart rot, except for demethoxylation, and a slight preference for hemicellulose degradation. Therefore, the results obtained suggest that the classification of I. obliquus as preferential lignin degrader (white-rot fungus) should be revised and clarified by further studies. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Thin films of polyazulene (PAz) are produced by using an optimized atmospheric pressure–vapor phase polymerization (AP-VPP) method. Method optimization is carried out by studying the effect of cell temperature, substrate temperature, polymerization time, and washing-solvent on film properties like optical bandgap, sheet resistance, surface roughness, and % transmittance (%T). Multi-layered PAz films were produced by layer-by-layer engineering. The effects of thin, electroactive multiple layers on film properties are investigated. UV–Vis, IR, and Raman analysis are utilized to understand the extended conjugation length and nature of the charge carriers. The spectroscopic data revealed the anomalous behaviour of PAz at a high level of doping. The proportion and amount of quinoid conformation is discussed. The addition of layers changes the transport of ions across the electroactive PAz films, which is studied using cyclic voltammetry at various scan rates. AFM and SEM images reveal a change in structural properties which is further correlated with a deviation of capacitance values at elevated scan rate. Comparison with earlier reported literature on electrochemically and chemically synthesized PAz is also provided. The conductivity, transparency and high capacitance show a promising application of AP-VPP PAz in various fields.

Despite the vast array of solution- and solid-state bio-analytical, bioelectronic and optoelectronic applications of cationic polythiophenes (CPTs), the number of studies focused on the role of hydrogen bonding (H-bonding) between these and other molecules is scarce, regardless of whether H-bonding is expected to play an important role in several such applications. Also, despite the advantages of using cosolvents to systematically examine the molecular interactions, there are no such studies for CPTs to our knowledge. This work presents a steady-state UV-vis/fluorescence spectroscopic, kinetic and thermodynamic study on the H-bonding interactions between a water-soluble, cationic-anionic (isothiouronium-tetraphosphonate), polythiophene-fullerene donor-acceptor pair with two-point, charge-assisted H-bonding (CAHB) capabilities, tuned using water or a 1,4-dioxane-water mixture (W-DI). Both solvents generate photoinduced electron transfer (PET), fluorescence resonance energy transfer (FRET), spontaneous binding, H-bonding, ground-state complexing via multiple site binding, formation of micelle-like aggregates and equivalence points at a similar concentration of the quencher. However, in comparison with water, W-DI promotes less-ordered, less packed micellar aggregates, due to hydrophobic desolvation of the H-bond and larger solvent displacement during the PT1-4Fo complexation. This would decrease the extent of charge-transfer and the size of the sphere-of-quenching, mainly by displacements or rotations of the H-bonds, instead of elongations, together with a possible larger extent of diffusion-controlled static quenching. At [4Fo] larger than the equivalence point the micelles formed in water do not have available binding sites due to a tighter aggregation, causing a decrease in the quenching efficiency, while the micelles formed in W-DI start showing larger quenching efficiencies, possibly due to an increase in entropy that overcomes the desolvation of the H-bonding. These results could be useful when analyzing outputs from systems including CPTs with H-bonding capabilities, operating in (or casted from) solvents with clear differences in polarity and/or H-bonding capacity.