Electron Acceptor Research Articles

Theoretical study on the efficiency of new organic dyes based on (E)-2-(2-(thiophen-3-yl)vinyl)-1,1′-bipyrrole as dye-sensitized solar cell sensitizers

Dye-sensitized solar cells (DSSCs) have gained critical importance as a leading emerging photovoltaic technology for low-cost power generation due to their simple production, light weight, applicability to the development of flexible photovoltaic devices, and use of abundant and inexpensive materials, including advantageous metal-free organic dyes. In this context, as a continuation of our work on DSSCs, a theoretical examination using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) was conducted to evaluate the photovoltaic performance of eight new organic dyes. Each dye contains an electron donor group ((E)-2-(2-(thiophen-3-yl)vinyl)-1,1′-bipyrrole), an electron acceptor group (cyanoacrylic acid (CCA)), and four auxiliary donor/acceptor groups, i.e., 3,4-ethylenedioxythiophene (EDOT), furan/benzothiadiazole (BTZ), diketopyrrolopyrrole (DPP) linked to π-conjugated bridges such as styrene or thiophene. We calculated several parameters for each dye, including EHOMO, ELUMO, Egap, λmax, Eex, pen-circuit photovoltage (VOC), light harvesting efficiency (LHE), regeneration driving force (ΔGreg), electron injection driving force (ΔGinject), and excitation lifetime (τ) to determine the photovoltaic efficiency of each dye. The results showed that the new dyes exhibited good performance and remarkable energy-conversion efficiencies. Additionally, all investigated dyes posed as promising candidates for the generation of effective DSSC sensitizers, particularly M6, which contained a styrene-linked EDOT auxiliary donor group.

Tuning the photovoltaic potential of thiazole based materials via incorporation of selenophene and electron acceptors rings at peripheral positions: A DFT approach

The non-fullerene acceptor (NFA) chromophores have sparked scientific and economic interest, due to their rapid advancements in power conversion efficiencies. Therefore, a series of new chlorothiazole based compounds (STM1-STM6) with A1–π–A2–π–A1 configuration was designed using reference chromophore (STMR). Structural modifications were made via incorporating selenophene and extended acceptor units, to enhance photovoltaic response in the designed materials. Density functional theory/time dependent-density functional theory (DFT/TD-DFT) calculations were executed at M06/6-311G (d,p) level to investigate key electronic and photovoltaic properties of STM1-STM6. So, various analyses such as UV–Visible, frontier molecular orbitals (FMOs), transition density matrix (TDM), density of states (DOS), open circuit voltage (Voc) and binding energy (Eb) were conducted to comprehend the photovoltaic properties. The designing in structural aspects with terminal acceptors and π-linker induced a reduction in energy gaps (ΔE = 2.078–2.237 eV) with an enhancement in the bathochromic shift (λmax = 744.650–798.250 nm in chloroform) than reference compound. A higher exciton dissociation rate was observed in all the compounds due to lower binding energy values (Eb = 0.525–0.572 eV). Additionally, TDM and DOS findings further endorsed the effective charge delocalization from HOMO to LUMO. Among all the examined compounds, STM3 exhibited the smallest band gap (2.078 eV), highest absorption maxima (798.250 nm), and the lowest exciton binding energy (0.525 eV), indicating significant electronic properties. Moreover, Voc analysis was conducted with respect to HOMOPBDBT-LUMOacceptor for all the designed chromophores; consequently, STM2 demonstrated a substantial Voc value of 1.647 V. Similarly, electron hole analysis was also conducted and significant electron and hole density was observed in all the investigated compounds, especially in STM2. The entitled compounds with photovoltaic potential would be considered as promising materials for the development of solar energy devices.

Interplay between photosynthetic electron flux and organic carbon sinks in sucrose-excreting Synechocystis sp. PCC 6803 revealed by omics approaches

BackgroundAdvancing the engineering of photosynthesis-based prokaryotic cell factories is important for sustainable chemical production and requires a deep understanding of the interplay between bioenergetic and metabolic pathways. Rearrangements in photosynthetic electron flow to increase the efficient use of the light energy for carbon fixation must be balanced with a strong carbon sink to avoid photoinhibition. In the cyanobacterium Synechocystis sp. PCC 6803, the flavodiiron protein Flv3 functions as an alternative electron acceptor of photosystem I and represents an interesting engineering target for reorganizing electron flow in attempts to enhance photosynthetic CO2 fixation and increase production yield.ResultsWe have shown that inactivation of Flv3 in engineered sucrose-excreting Synechocystis (S02:Δflv3) induces a transition from photoautotrophic sucrose production to mixotrophic growth sustained by sucrose re-uptake and the formation of intracellular carbon sinks such as glycogen and polyhydroxybutyrate. The growth of S02:Δflv3 exceeds that of the sucrose-producing strain (S02) and demonstrates unforeseen proteomic and metabolomic changes over the course of the nine-day cultivation. In the absence of Flv3, a down-regulation of proteins related to photosynthetic light reactions and CO2 assimilation occurred concomitantly with up-regulation of those related to glycolytic pathways, before any differences in sucrose production between S02 and S02:Δflv3 strains were observed. Over time, increased sucrose degradation in S02:Δflv3 led to the upregulation of respiratory pathway components, such as the plastoquinone reductase complexes NDH-11 and NDH-2 and the terminal respiratory oxidases Cyd and Cox, which transfer electrons to O2. While glycolytic metabolism is significantly up-regulated in S02:Δflv3 to provide energy for the cell, the accumulation of intracellular storage compounds and the increase in respiration serve as indirect sinks for photosynthetic electrons.ConclusionsOur results show that the presence of strong carbon sink in the engineered sucrose-producing Synechocystis S02 strain, operating under high light, high CO2 and salt stress, cannot compensate for the lack of Flv3 by directly balancing the light transducing source and carbon fixing sink reactions. Instead, the cells immediately sense the imbalance, leading to extensive reprogramming of cellular bioenergetic, metabolic and ion transport pathways that favor mixotrophic growth rather than enhancing photoautotrophic sucrose production.

Femtosecond Dynamics of the Excited Primary Electron Donor in Reaction Centers of the Purple Bacterium Rhodobacter sphaeroides.

Femtosecond transient absorption spectroscopy was used to study the dynamics of the excited primary electron donor in the reaction centers of the purple bacterium Rhodobacter sphaeroides. Using global analysis and the interval method, we found a correlation between the vibrational coherence damping of the excited primary electron donor and the lifetime of the charge-separated stateP+BA-, indicating the reversibility of electron transfer to the primary electron acceptor, theBA molecule. In the reaction centers, the signs of superposition of two electronic states of P were found for a delay time of less than 200fs. It is suggested that the admixture value of the charge transfer statePA+PB- with the excited primary electron donorP* is about 24%. The results obtained are discussed in terms of the two-step electron transfer mechanism.

Click Synthesis of Tweezer Dyads for H‐Bond Assisted Cooperativity in Tandem Uncaging Systems

Abstract: “Tandem” uncaging systems, in which a photolabile protecting group (PPG) is sensitized by an energy‐harvesting antenna, may increase the photosensitivity of PPGs by several orders of magnitude for two‐photon (2P) photorelease. Yet, they remain poorly accessible because of arduous multi‐step synthesis. In this work, we design efficient tandem uncaging systems by (i) using a convenient assembly of the building blocks relying on click chemistry, (ii) H‐bonding induced proximity thus facilitating (iii) photoinduced electron transfer (PeT) as a cooperative mechanism. A strong two‐photon absorber electron‐donating quadrupolar antenna and various electron‐accepting PPGs (mDEAC, MNI or MDNI) were clicked stepwise onto a “tweezer‐shaped” pyrido‐2,6‐dicarboxylate platform whose H‐bonding and p‐stacking abilities were exploited to keep the antenna and the PPGs in close proximity. The different electron acceptor ability of the PPGs led to dyads with wildly different behaviors. Whilst the MDNI and MNI dyads showed poor dark stability or no photo‐uncaging ability due to their too high electron accepting character, the mDEAC dyad benefited from optimum redox potentials to promote PeT and slow down charge recombination, resulting in enhanced uncaging quantum yield (Fu=0.38) compared to mDEAC (Fu=0.014). The unique resulted in large 2P photo‐sensitivity in the near‐infrared window (240 GM at 710 nm).

Enhanced Thermally Activated Delayed Fluorescence by Sole Coordination: From an Organic Molecule to Its Zinc Complex.

A BPAPTPyC organic molecule containing a sandwich structural chromophore is designed and synthesized to produce blue thermally activated delayed fluorescence (TADF). The chromophore is composed of two di(4-tert-butylphenyl)amino donors and one inserted terpyridyl acceptor hitched at positions 1, 8, and 9 of a single carbazole via the p-phenylene group, in which the multiple space π-π interactions between the donor and acceptor enable the molecule to possess the TADF feature with a high energy emission at 470 nm but a low photoluminescence quantum yield (PLQY) and a small proportion of the delayed component. In contrast, the corresponding Zn(BPAPTPyC)Cl2 complex has a high PLQY and a short lifetime with a red-shifted emission due to the enhanced rigidity and electron accepting ability of the terpyridyl group from coordination. A solution-processed organic light-emitting diode (OLED) based on the complex achieves a maximum external quantum efficiency (EQE) of 17.9% with an emission peak at 585 nm, while an OLED of the organic molecule produces blue emission with a maximum EQE of 2.7%.

Redox state of plastoquinone QA and lifetime of the P680 +•Pheo ‒• pair in photosystem II reaction centers

When plastoquinone QA (the electron acceptor) presents in one- or two-electron reduced states, the energy barrier between the radical pair and the excited photoactive chlorophyll ( ) in the photosystem II (PSII) reaction centers was estimated to be ~0.06 eV and ~0.12 eV, respectively (Safarova et al., 2023). In this study, the effect of the one- and two-electron reduced states of plastoquinone on the lifetime of the pair formed in the primary photochemical reaction in the PSII reaction center was evaluated. It has been shown that the lifetime of the pair formed when plastoquinone is doubly reduced is ≥10 times greater than when plastoquinone undergoes single reduction (recombination of charges, accordingly, occurs at a ≥10 times lower rate). The obtained result was compared with the existing experimental data. Keywords: Photosystem II, plastoquinone, charge recombination, lifetime

Large scale photocatalytic hydrogen production from original natural Yellow River water and solvent (0.35 M Na2S and 0.25 M Na2SO3) over nano Cu@graphdiyne/Zn0.5Cd0.5S photocatalyst

The Zn0.5Cd0.5S material holds significant promise for employment in photocatalytic hydrogen evolution. However, it face an issue of photogenerated electrons, resulting in an elevated rate of photogenerated electron-hole recombination. To tackle this challenge, we propose a remedy utilizing a dual built-in electric field. This is accomplished by leveraging the distinct properties of graphdiyne, which can serve as either an electron donor or acceptor. To create the dual built-in electric field, we first grow a thin layer of graphdiyne on the surface of Nano Cu, forming the first layer. The subsequent layer consists of another graphdiyne thin layer combined with Zn0.5Cd0.5S. Upon exposure to light, Zn0.5Cd0.5S produces a substantial number of photogenerated electrons, which can swiftly move under the influence of the dual built-in electric field. In experiments conducted under square meter conditions with a reaction environment of 0.35 M Na2S and 0.25 M Na2SO3, hydrogen evolution reached a production quantity of 106,689 µmol within 30 h. In another experiment conducted with original natural water from the Yellow River, the production quantity amounted to 334 µmol within 84 h. Under 5 W simulated sunlight and 108 hours in pure water, 178 µmol of hydrogen and 50 µmol of oxygen were generated.

The monotopic quinone reductases from Staphylococcus aureus

Staphylococcus aureus, a Gram-positive bacterium, is an opportunistic pathogen and one of the most frequent causes for community acquired and nosocomial infections that has become a major public health threat due to the increased incidence of its drug resistance. Although being a prominent pathogen, its energetic metabolism is still underexplored, and its respiratory enzymes have been escaping attention. S. aureus can adapt to different environmental conditions by performing both aerobic and anaerobic respirations, which is particularly important as it frequently colonizes niches with different oxygen concentrations. This adaptability is derived from the composition of its respiratory chain, specifically from the presence of terminal electron acceptor reductases. The plasticity of S. aureus energy metabolism is enlarged by the ten quinone reductases encoded in its genome, eight of them being monotopic proteins. The role of these proteins is critical as they connect the different catabolic pathways to the respiratory chain. In this work, we identify, describe, and revise the monotopic quinone reductases present in S. aureus, providing an integrated view of its respiratory chain.

Ligand-free Cs2PdBr6 perovskite microcrystals with narrow bandgap and high photoelectrochemical performance in aqueous solution

The exploration of efficient lead-free perovskite photoelectric active materials to develop high-performance photoelectrochemical (PEC) systems in aqueous solution is crucial to expand their PEC applications. Herein, we successfully constructed a high-performance PEC platform using ligand-free perovskite Cs2PdBr6 microcrystals (MCs) as the photoactive substance. The Cs2PdBr6 MCs showed narrow bandgap, wide absorption range, high electronic mobility and good stability in aqueous solutions. Particularly, the Cs2PdBr6 MCs exhibited an excellent photoresponse, the photocurrent density could reach as high as 98 μA/cm2 under 10.18 mW/cm2 light irradiation in the absence of other electron acceptors. In addition of the extremely wide range of response wavelength, wide pH range and accelerated interfacial carrier transfer, the Cs2PdBr6 MCs demonstrated the significant potential of photocathode active material for applications in PEC sensors and optoelectronic devices. Therefore, this work indicates that Cs2PdBr6 MCs design is a highly efficient way to solve the intrinsic issues of perovskite material, predicting a promising strategy for high performance PEC application in aqueous ambience.

Rosettibacter primus gen. nov., sp. nov., and Rosettibacter firmus sp. nov., facultatively anaerobic moderately thermophilic bacteria of the class Ignavibacteria from hot springs of North Ossetia

A novel facultatively anaerobic moderately thermophilic bacteria, strains 4137-MeT and 4148-MeT, were isolated from hot springs of Karmadon and Ursdon, respectively (North Ossetia, Russian Federation). Gram-negative, motile rods were present singly, in pairs, rosettes, and aggregates, or formed biofilms. Both strains grew optimally at 50–55 °C, pH 7.0 and did not require sodium chloride or yeast extract for growth. They were chemoorganoheterotrophs, growing on mono-, di- and polysaccharides (cellulose, starch, xylan, lichenan, galactan, xyloglucan, mannan, xanthan gum, guar gum) as well as proteinaceous substrates (gelatin, peptone, beef and yeast extract). Growth under anaerobic conditions was observed in presence and absence of external electron acceptors. Sulfur, thiosulfate, arsenate, Fe-citrate, and ferrihydrite were reduced with acetate, starch, or yeast extract as electron donors. The respiratory quinone was MK-7. Major cellular fatty acids of both strains were iso-C15:0, anteiso-C17:0, C15:0, iso-C16:0 and additionally iso-C17:0 for strain 4137-MeT. The size of the genome and genomic DNA G + C content of strain 4137-MeT were 3.24 Mb. and 29.9 %, respectively; for strain 4148-MeT – 3.33 Mb and 30.7 %. According to the 16S rRNA gene sequence and conserved protein sequences phylogenies, strains 4137-MeT and 4148-MeT represented a distinct lineage of the family Melioribacteraceae within the class Ignavibacteria. Based on phylogenetic analysis and phenotypic features, the novel isolates were assigned to a novel genus, for which the name Rosettibacter gen. nov. is proposed. Strain 4148-MeT represents its type species Rosettibacter primus sp. nov., while strain 4137-MeT represents a new species Rosettibacter firmus sp. nov.

Salinity and nutrient condition as key factors drive the assembly of sediment prokaryotic communities

Despite extensive research on the geographical patterns of microbial communities, our comprehension of the mechanisms underlying their spatial distribution is still limited. Natural ecosystems provide opportunities to investigate the structure, connectivity, and assembly processes of prokaryotic communities. Saline lakes, mangroves, ocean margins, cold seeps, and open oceans as five distinct natural ecosystems exhibit varied levels of salinity and nutrient condition (carbon sources, electron donors, and electron acceptors). Based on the analysis of 197 sets of published 16S rRNA gene amplicon sequencing data on sediment samples of the five habitats, differences in salinity and nutrient conditions were identified to play a critical role in governing the composition, connectivity, and assembly process of prokaryotic communities. Specifically, unique prokaryotic community patterns were observed in these habitats, e.g., mangrove sediment communities were shown to have the highest alpha diversity and the lowest community-level ribosomal RNA gene operon (rrn) copy numbers, compared to the open ocean sediment communities. Positive correlation predominated connections (>80% of total connections) of the prokaryotic microbial networks in the five habitats. Communities within nutrient-rich saline lake and cold seep sediments exhibit the strongest and closest connections. Using the dissimilarity-overlap curve and null model, differences in composition, connectivity, and assembly process were found to be predominantly governed by deterministic forces. These findings enhance our understanding of microbial ecology in typical saline environments and enable us to investigate intricate ecosystems.

Selective separation of rhenium from oxygen-pressure leach solution of molybdenite concentrate using modified D201 resin: Experiments and theoretical calculations

Recovering rhenium from highly acidic rhenium-containing leach solutions is challenging for most resins, particularly in multiplexed systems. Herein, we introduce a scheme for selectively obtaining rhenium from a multielement solution containing high concentrations of sulfuric acid using modified D201 resin. Considering the dosage of resin and parameters such as pH and adsorption temperature, the adsorption efficiencies under optimal conditions for rhenium, molybdenum, iron, and cerium were 97.46 %, 0.38 %, 0.94 %, and 1.10 %, respectively. The selective recovery mechanism of rhenium was investigated by fitting the experimental data to kinetic and adsorption isotherm models. The pseudo-second-order and Langmuir models better fit results corresponding to the experimental data, which indicates monolayer chemisorption of ReO4− formed on the resin surface. Meanwhile, various characterizations such as SEM-EDS, FTIR, XPS, etc., indicate that ReO4− initially combines with the protonated −CHN+H2CH2Cl on the modified resin surface and then undergoes ion exchange reaction with doped Cl−. Furthermore, because of the diverse forms and similar properties of molybdenum and rhenium ions in acidic solutions, a theoretical model based on density functional theory was used to simulate the selective adsorption process in leach solution with a pH of 1.7. The simulation results demonstrate a highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap, observed in the following order: ΔEMoO22+ = ΔEReO4− < ΔEMoO42− < ΔEMo7O246−, which implies that MoO22+ and ReO4− were most likely to transition from their ground states to excited states and react with the electron donor and acceptor groups, respectively. Compared with MoO42−, ReO4− is more likely to react with the electron acceptor group and provides the corresponding methods and a theoretical reference for selective separation of rhenium in multielement solutions.

Effects of anaerobic oxidation of methane (AOM) driven by iron and manganese oxides on methane emissions in constructed wetlands and underlying mechanisms

In recent years, anaerobic oxidation of methane with iron and manganese oxides as electron acceptors has been confirmed to exist in electrochemical constructed wetlands (CW), and this process is an important way to reduce methane emissions. However, the internal mechanisms of emission reduction, microbial ecological networks, and electron transfer mechanisms remain unclear. In this study, we found that AOM driven by iron and manganese oxides (Fe/Mn-AOM) reduced methane emissions by more than 50.86% in constructed wetland – microbial fuel cell (CW-MFC) systems. In iron and manganese systems, the relative abundance of microorganisms associated with methane metabolism (methanotrophic bacteria) increased significantly. AOM-related microorganisms cooperated with other microorganisms to form a robust and stable microbial ecological network. In the process of methane metabolism, there was an increase in the proportion of reverse methanogenic genes in iron and manganese systems, with the proportion of mcr genes being 1.75 and 1.79 times that of control systems. The key genes (cyc1 and cox11) that influence cytochrome C synthesis in AOM process were significantly enriched, resulting in enhanced electron transfer process. The coexistence of iron and manganese oxides enabled the simultaneous biochemical processes of CH4 oxidation and CO2 reduction within a single system. Additionally, the increase in humic acid also facilitated electron transfer, thereby significantly enhancing the removal efficiency of COD, TN, and TP in the CW-MFC systems. This study reveals the potential mechanism of Fe/Mn-AOM for CW-MFC methane emission reduction, which can provide a theoretical basis for the collaborative treatment of sewage and methane control in CWs, so as to achieve the maximum environmental benefits of CW.

Rational design of g-C3N4-based photocatalysts with intramolecular donor-acceptor structures for deep oxidation of emerging organic micropollutants

An in-situ route for the fabrication of intramolecular electron donor-acceptor (D-A) structured g-C3N4 photocatalysts is developed by the preorganization of urea with the precursor of electron donor units, such as 4-iodobenzaldehyde, 5-bromo-2-thiophenaldehyde and 5-bromo-2-furaldehyde, followed by thermal polymerization. In the resulting benzene unit-, thiophene unit- and furan unit-based D-A structured g-C3N4 photocatalysts, namely, BHCNx, SCNx, and OCNx, the incorporated electron donor units (i.e., benzene units, thiophene units and furan units) link with the electron acceptors (i.e., heptazine units) through CN and CN covalent bonds. In comparison of bulk g-C3N4, all D-A structured g-C3N4 display notably enhanced visible-light photocatalytic oxidation activity in the degradation of emerging organic micropollutants, p-nitrophenol (PNP) and methylparaben (MPB), in which the apparent first-order kinetic constant of the optimized BHCN2, SCN2, and OCN2 is 1.6, 3.0 and 6.8 times higher than bulk g-C3N4 for PNP degradation and 1.9, 3.4 and 2.6 times higher than bulk g-C3N4 for MPB degradation. Importantly, the micropollutants can be not only degraded but also mineralized completely. The catalysts are also robust in the removal of mixed emerging organic micropollutants in pharmaceutical wastewater, exhibiting potential of dealing with organic micropollutants in wastewater. Mechanism studies reveal that the unique intramolecular charge transfer process in the catalysts enhances visible-light harvesting capacity, boosts directional transfer of the photogenerated charges and increases adsorption towards oxygen molecules. These collective improvements can maximum utilization the photogenerated electrons and holes to yield plentiful reactive oxygen species for deep oxidization of the pollutants.

Molecular Copper(I)-Sensitized Photoanodes for Alcohol Oxidation under Ambient Conditions.

Dye-sensitized photoelectrochemical cells can enable the production of molecules currently accessible through energetically demanding syntheses. Copper(I)-based dyes represent electronically tunable charge transfer and separation systems. Herein, we report a Cu(I)-bisdiimine donor-chromophore-acceptor dye with an absorbance in the visible part of the solar spectrum composed of a phenothiazine electron donor, and dipyrido[3,2-a:2',3'-c]phenazine electron acceptor. This complex is incorporated onto a zinc oxide nanowire semiconductor surface effectively forming a photoanode that is characterized spectroscopically and electrochemically. We investigate the photo-oxidation of hydroquinone, and the photosensitization of 2,2,6,6-tetramethylpiperidine-1-oxyl and N-hydroxyphthalimide for the oxidation of furfuryl alcohol to furfuraldehyde, resulting in near quantitative conversions, with poor selectivity to the alcohol.

Aerobic and anaerobic mineralisation of sediment organic matter in the tidal River Elbe

PurposeThe share of microbially degradable sediment organic matter (SOM) and the degradation rate depend, among others, on the intrinsic properties of SOM as well as on the type and concentration of terminal electron acceptors (TEA). Next to its role as TEA, molecular oxygen enhances SOM decay by oxygenase-mediated breakdown of complex organic molecules. This research investigated long-term SOM decay (> 250 days) under aerobic and anaerobic conditions to (1) provide a basis for sediment carbon flux estimates from the River Elbe estuary and (2) assess the potential for carbon burial in relation to redox conditions and dredging interventions.MethodsLong-term aerobic and anaerobic SOM decay in fluid mud, pre-consolidated and consolidated sediment layers was investigated over three years along a transect of ca. 20 km through the Port of Hamburg, starting at the first hydrodynamically determined hotspot of sedimentation after the weir in Geesthacht. Absolute differences between aerobic and anaerobic cumulative carbon mineralization were calculated, as well as their ratio. Findings were correlated to a suite of solids and pore water properties.ResultsSOM decay followed first order multi-phase exponential decay kinetics. The ratio between C release under aerobic and anaerobic conditions ranged around 4 in the short-term, converging to a value of 2 in the long term. Strong gradients in absolute C release along the upstream–downstream transect did not reflect in a corresponding gradient of the aerobic-anaerobic ratio. C release was most strongly correlated to the water-soluble organic matter, in particular humic acids. Contact of anaerobically stabilized sediment with the oxygenated water phase induced significant release of carbon.ConclusionSOM degradability in the study area exhibited strong spatial gradients in relation to the organic matter source gradient but was mainly limited by the high extent of organic matter stabilization. Under these conditions, molecular oxygen as TEA provides little thermodynamic advantage. Carbon-sensitive sediment management, considering SOM reactivity patterns in stratified depositional areas, is a powerful strategy to reduce environmental impacts of dredging measures.

Non-sealed water hastens the efficiency of microbial electrochemical remediation system

Soil petroleum hydrocarbon contamination has become a global problem and microbial remediation is a friendly technology. The scarcity of electron acceptors and the low activity of functional microbes are limiting factors which are overcome by the soil microbial electrochemical system (MES). Using the petroleum hydrocarbon polluted soils as substrates, soil MESs were constructed with four different water-sealed levels to optimize the system configuration. After 65 days of operation, the accumulated charge of the group with the lowest water level (MES0) was 1282 C, while that of the highest water level group (MES5) was only 151 C. Compared with the original soil (OS), the hydrocarbon removal near the anode and cathode in MES0 were 28%–30%, which were 4%–11% higher than those in MES5. Additionally, the co-occurrence networks analysis revealed dominance in positive than negative links among bacterial, fungal, and archaeal communities in MES0 compared to MES5 and OS. In MES0 bacteria were more densely populated and connected into more closely related groups with higher interactions than those in MES5 as well as in OS. Contrary to bacteria, MES5 favored the growth and connections of fungal and archaeal communities compared to those in MES0. The above changes were ascribed to the dissolved oxygen, redox potential, and reduction of resistance, which shifted the electron acceptors hence contributing to the process of electrons and substrates transfer in soil, suggesting that bacteria synergistically cooperated with fungi, and archaea in the removal mechanisms of hydrocarbons in the MES. Our findings revealed the optimization of low water seal on the MES performance by providing a detailed overview of the synergistic behavioral characteristics of bacterial, fungal, and archaeal in soil MESs.

Organic Visible‐Blind Ultraviolet Photodiodes and Pixel‐Array Imagers Based on [1]Benzothieno[3,2‐b]Benzothiophene (BTBT) Derivatives

AbstractVisible‐blind ultraviolet (VBUV) photodetectors are designed for UV detection without responding to visible light, thus having many applications in communications, flame detection, environment monitoring, and astronomy. Herein, an organic device concept based on the bulk heterojunction (BHJ) photodiode is presented for high‐performance VBUV photodetection and imaging. The BHJ, comprised of an organic electron donor, 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene (C8‐BTBT), and an electron acceptor, indene‐C60 bisadduct (ICBA), shows efficient generation and transport of free charges upon UV irradiation. The organic photodiode (OPD) delivers exceptional VBUV photodetection performance. At a low voltage of −0.5 V, the device exhibits a wide linear dynamic range of 98.15 dB. Furthermore, the OPD can detect ultra‐low light intensities down to 0.58 µW cm−2 with a high photoresponsivity of 0.12 A W−1 and specific detectivity of 2.75 × 1012 Jones. More importantly, by integrating the OPD with a readout integrated circuit, the pixel‐array organic VBUV imager is demonstrated to have high‐quality imaging capability. The results reveal a novel strategy to design VBUV photodetectors and imagers with balanced performance, cost, area, flexibility, and power consumption.

Aerobic denitrification as an N2O source from microbial communities.

Nitrous oxide (N2O) is a potent greenhouse gas of primarily microbial origin. Oxic and anoxic emissions are commonly ascribed to autotrophic nitrification and heterotrophic denitrification, respectively. Beyond this established dichotomy, we quantitatively show that heterotrophic denitrification can significantly contribute to aerobic nitrogen turnover and N2O emissions in complex microbiomes exposed to frequent oxic/anoxic transitions. Two planktonic, nitrification-inhibited enrichment cultures were established under continuous organic carbon and nitrate feeding, and cyclic oxygen availability. Over a third of the influent organic substrate was respired with nitrate as electron acceptor at high oxygen concentrations (>6.5mg/L). N2O accounted for up to one-quarter of the nitrate reduced under oxic conditions. The enriched microorganisms maintained a constitutive abundance of denitrifying enzymes due to the oxic/anoxic frequencies exceeding their protein turnover-a common scenario in natural and engineered ecosystems. The aerobic denitrification rates are ascribed primarily to the residual activity of anaerobically synthesised enzymes. From an ecological perspective, the selection of organisms capable of sustaining significant denitrifying activity during aeration shows their competitive advantage over other heterotrophs under varying oxygen availabilities. Ultimately, we propose that the contribution of heterotrophic denitrification to aerobic nitrogen turnover and N2O emissions is currently underestimated in dynamic environments.