Electron Transfer Distance Research Articles

Highly active Cu2O/CoCo-PBA S-scheme heterojunction for enhanced visible-light-driven hydrogen evolution

Prussian blue analogues is a unique class of organic-inorganic hybrid materials that have garnered significant attention in the field of photocatalysis due to their large specific surface area and abundant active sites. However, their potential is limited by the challenge of photogenerated charge carrier recombination. To address this issue, we successfully synthesized a tightly coupled Cu2O/CoCo-PBA S-scheme heterojunction catalyst using ultrasound-assisted and thermal treatment methods, aiming to reduce the recombination of photogenerated charge carriers. In this system, CoCo-PBA serves as the electron donor, while Cu2O acts as the electron acceptor. The closely coupled interface between these materials shortens the electron transfer distance. Under 10 W white light irradiation, the Cu2O/CoCo-PBA composite photocatalyst demonstrated remarkable hydrogen evolution activity, with a hydrogen production rate of 5.98 mmol⋅g⁻¹⋅h⁻¹, which is 6.4 times that of CoCo-PBA alone. This S-scheme heterojunction strategy lays the groundwork for the design and large-scale application of highly active visible-light-driven photocatalysts.

Fully Integrated Biosensing System for Dynamic Monitoring of Sweat Glucose and Real-Time pH Adjustment Based on 3D Graphene MXene Aerogel.

The development of noninvasive glucose sensors capable of continuous monitoring without restricting user mobility is crucial, particularly for managing diabetes, which demands consistent and long-term observation. Traditional sensors often face challenges with accuracy and stability that curtail their practical applications. To address these issues, we have innovatively applied a three-dimensional porous aerogel composed of Ti3C2Tx MXene and reduced graphene oxide (MX-rGO) in electrochemical sensing. It significantly reduces the electron-transfer distance between the enzyme's redox center and the electrode surface while firmly anchoring the enzyme layer to effectively prevent any leakage. Another pivotal advancement in our study is the integration of the sensor with a real-time adaptive calibration mechanism tailored specifically for analyzing sweat glucose. This sensor not only measures glucose levels but also dynamically monitors and adjusts to pH fluctuations in sweat. Such capabilities ensure the precise delivery of physiological data during physical activities, providing strong support for personalized health management.

S-scheme charge transfer pathway in a hierarchical BiOCl0.7I0.3-P/TiO2 heterojunction for bifunctional bacterial inactivation and antibiotic degradation

Photocatalytic technology holds significant importance and feasibility in bacterial inactivation and antibiotic degradation. This study successfully fabricated a hierarchical inorganic BiOCl0.7I0.3-P/TiO2 (BOCI-P/TH) S-scheme heterojunction by in-situ growth of BiOCl0.7I0.3-P (BOCI-P) nanosheets on TiO2 hollow spheres (TH), which was capable of suppressing charge carrier recombination and enhancing oxidative-reductive capability. The charge transfer mechanism of the hierarchical BOCI-P/TH composite was elucidated by radical-trapping electron paramagnetic resonance and X-ray photoelectron spectroscopy analysis, revealing the mechanism behind high activities of the BOCI-P/TH photocatalysts in antibacterial and degradation. It was found that the multiple light-scattering in hierarchical structure enhanced the light absorption, tight contacted interface decreased electron transfer distance, and S-scheme charge transfer inhibited charge recombination. As a result, electrons and holes with strong redox ability were generated, resulting the formation of abundant ·O2- and ·OH radicals, achieving efficient sterilization and antibiotic degradation. The BOCI-P/TH catalysts exhibited outstanding photocatalytic activity and photostability for deactivating Staphylococcus aureus (99.99%) and degrading Rhodamine B (99.98%), tetracycline hydrochloride (84.81%), and ofloxacin (99.95%). This research provided valuable insights into the multi-strategy design of photocatalysts and the application of dual-functional catalysts in various environments.

Shortening electron transfer distance to enhance chemicals and electric energy production in Escherichia coli

Intracellular electron abundance affects the efficiency of biosynthetic pathways in microbial cell factories. However, regulating electron transfer efficiency to change intracellular electron abundance is challenging. Herein, we aimed to improve the electron transfer efficiency by shortening electron transfer distance using two systems: an extracellular electron transfer system (EET) and a light-driven intracellular electron regeneration system (ERS). The EET involved reconstructing an efficient electron transfer pathway (AEC4) and using periplasmic and biofilm engineering to improve its efficiency, whereas the ERS involved developing a biologically self-synthetic photosynthetic biohybrid system and using protein cage engineering to enhance its efficiency. As a proof of concept, the EET was implemented using a dynamic AND logic gate to increase the α-ketoglutarate titer to 30.4 g/L and the power density to 561.5 mW/m2 in microbial fuel cells. In a 5 L fermenter, the titer and productivity of α-ketoglutarate reached 67.7 g/L and 1.88 g/L/h, respectively. The ERS was manipulated using a chemo-optogenetic AND logic gate to increase the adipate titer to 43.1 g/L in a 5 L fermenter. Overall, our results provide a potential way to shorten electron transfer distance for the efficient production of valuable chemicals and electric energy.

In situ proof construction of GDY/NiWO4/CdS double S-scheme heterojunction: Improving charge transfer and promoting photocatalytic activity

In the field of photocatalysis, the inherent properties of catalysts are a hard condition that affects catalytic performance, and constructing heterojunctions is a common method to improve catalyst defects and enhance catalyst performance. This article makes effective use of the outstanding stability and unique electronic structure of graphdiyne, along with its excellent semiconductor properties comparable to silicon. It uses these properties to attach rod-shaped CdS and microspherical NiWO4 onto sheet-like graphdiyne, creating an S-scheme heterojunction. With the construction of S-scheme heterojunctions and the special contact methods between the three, the physical potential barrier and the distance of electron transfer are reduced. Furthermore, the combined impact of NiWO4 and graphdiyne works to inhibit the photo corrosion of CdS, enhance its electron transfer capabilities, decrease electron-hole recombination efficiency, and boost hydrogen evolution sites. This maximizes the redox potential during catalysis, leading to exceptional stability and efficiency of the composite catalyst. This study opens up a new avenue for leveraging the superior properties of graphdiyne and advancing sustainable practices.

Directional long-distance electron transfer from reduced to oxidized zones in the subsurface

Electron transfer (ET) is the fundamental redox process of life and element cycling. The ET distance is normally as short as nanometers or micrometers in the subsurface. However, the redox gradient in the subsurface is as long as centimeters or even meters. This gap triggers an intriguing question whether directional long-distance ET from reduced to oxidized zones exists along the redox gradient. By using electron-donating capacity variation as a proxy of ET, we show that ET can last over 10 cm along the redox gradient in sediment columns, through a directional long-distance ET chain from reduced to oxidized zones constituted by a series of short-distance electron hopping reactions. Microbial and chemical processes synergistically mediate the long-distance ET chain, with an estimated flux of 6.73 μmol e−/cm2 per day. This directional long-distance ET represents an overlooked but important “remote” source of electrons for local biogeochemical and environmental processes.

Strong electronic coupling of Mo2TiC2 MXene/ZnCdS ohmic junction for boosting photocatalytic hydrogen evolution

Effective electron coupling is an effective method to enhance hydrogen evolution dynamics. Herein, a Mo2TiC2 MXene/ZnCdS ohmic junction was constructed for boosting photocatalytic hydrogen evolution. The terminal groups on the surface of Mo2TiC2 MXene provide abundant active sites and adsorption sites for the catalyst. The 2D/0D structure of Mo2TiC2/ZnCdS forms a tight interfacial contact, providing the shortest transport distance for electron transfer. At the same time, the 2D structure Mo2TiC2 MXene prevents the aggregation of ZnCdS, causing it to expose more active sites. The results of DFT calculation and XPS show that there is an obvious strong electron coupling interface between Mo2TiC2 MXene and ZnCdS, which increases the local electron density of Mo2TiC2 MXene and inhibits electron backflow. The increase of the d-band center reduced the filling of anti-bonding states and increase the bonding strength of H2, promote the separation efficiency of photogenerated electrons and enhance the ability of photocatalytic hydrogen evolution. Therefore, 25 %Mo2TiC2/ZnCdS showed the best photocatalytic hydrogen evolution activity (17.73 mmol g−1 h−1), which was 3.15 times that of ZnCdS (5.62 mmol g−1 h−1). And AQE can reach 16.22 % at 475 nm. This work provides some insights for constructing ohmic junction based on MXene material to adjust the local electronic structure of catalyst for photocatalytic hydrogen evolution.

Redox Properties of Bacillus subtilis Ferredoxin:NADP+ Oxidoreductase: Potentiometric Characteristics and Reactions with Pro-Oxidant Xenobiotics.

Bacillus subtilis ferredoxin:NADP+ oxidoreductase (BsFNR) is a thioredoxin reductase-type FNR whose redox properties and reactivity with nonphysiological electron acceptors have been scarcely characterized. On the basis of redox reactions with 3-acetylpyridine adenine dinucleotide phosphate, the two-electron reduction midpoint potential of the flavin adenine dinucleotide (FAD) cofactor was estimated to be -0.240 V. Photoreduction using 5-deazaflavin mononucleotide (5-deazaFMN) as a photosensitizer revealed that the difference in the redox potentials between the first and second single-electron transfer steps was 0.024 V. We examined the mechanisms of the reduction of several different groups of non-physiological electron acceptors catalyzed by BsFNR. The reactivity of quinones and aromatic N-oxides toward BsFNR increased when increasing their single-electron reduction midpoint redox potentials. The reactivity of nitroaromatic compounds was lower due to their lower electron self-exchange rate, but it exhibited the same trend. A mixed single- and two-electron reduction reaction was characteristic of quinones, whereas reactions involving nitroaromatics proceeded exclusively via the one-electron reduction reaction. The oxidation of FADH• to FAD is the rate-limiting step during the oxidation of fully reduced FAD. The calculated electron transfer distances in the reaction with nitroaromatics were close to those of other FNRs including the plant-type enzymes, thus demonstrating their similar active site accessibility to low-molecular-weight oxidants despite the fundamental differences in their structures.

Adsorption and sensing characteristics of insulating gas C4F7N on 3d late transition metal‐phthalocyanine: Theoretical and experimental study

AbstractHeptafluoroisobutyronitrile (C4F7N) is being considered as a promising alternative to the greenhouse gas SF6 in the electrical industry. However, its biotoxicity necessitates the development of gas sensing technology to detect leaked C4F7N. A combination of density functional theory and experiments was employed to evaluate the adsorption and sensing performance of different metal‐phthalocyanines as potential sensing materials for C4F7N detection. The study included exploring adsorption configurations with adsorption energies, electron transfer, and adsorption distance, as well as comparisons of electronic properties, electron distribution, and density of states (DOS) among the MPcs. Furthermore, gas sensing experiments were conducted using different MPcs to detect 25–100 ppm C4F7N. The results revealed that Mn‐Pc, Fe‐Pc, Co‐Pc, and Zn‐Pc exhibited considerable chemical interactions, while Ni‐Pc and Cu‐Pc showed weaker adsorption strength. These findings were further elucidated based on the electron density and DOS of atomic orbitals. Moreover, gas sensing experiments indicated that Co‐Pc demonstrated a higher response compared to Fe‐Pc at the same concentration of C4F7N. Overall, the theoretical and experimental insights offer valuable guidance for C4F7N detection and provide a systematic approach to screen and explore organometallic polymer‐based gas sensors applicable in various fields.

Site-Specific Photochemistry along a Protonated Peptide Scaffold.

We present a detailed study of the time-dependent photophysics and photochemistry of a known conformation of the two protonated pentapeptides Leu-enkephalin (Tyrosine-Glycine-Glycine-Phenylalanine-Leucine, YGGFL) and its chromophore-swapped analogue FGGYL, carried out under cryo-cooled conditions in the gas phase. Using ultraviolet-infrared (UV-IR) double resonance, we record excited state IR spectra as a function of time delay between UV and IR pulses. We identify unique Tyr OH stretch transitions due to the S1 state and the vibrationally excited triplet state(s) formed by intersystem crossing, Tn(v). Photofragment mass spectra are recorded out of the S1 origin and following UV-IR double resonance. Several competing site-specific fragmentation pathways are discovered involving peptide backbone cleavage, Tyr side chain loss, and N-terminal NH3 loss mediated by electron transfer. In YGGFL, IR excitation in the S1 state promotes electron transfer (ET) from the aromatic ring to the N-terminal R-NH3+ group leading to loss of neutral NH3. This product channel is missing in FGGYL due to the larger distance for ET from Y(4) to NH3+. Selective loss of the Tyr side chain occurs out of an excited state process following UV excitation and is further enhanced by IR excitation in S1 and Tn(v) states of both YGGFL and FGGYL. Finally, IR excitation in the S1 or Tn(v) states fragments the peptide backbone exclusively at amide(4), producing the b4 cation. We postulate that this selective fragmentation results from intersystem crossing to produce vibrationally excited triplets with enough energy to launch the proton along a proton conduit present in the known starting structure.

Bismuth-Doped Carbon Dots Decorated Escherichia coli for Enhanced Hydrogen Production.

Photosynthetic inorganic biohybrid systems (PBSs) combining an inorganic photosensitizer with intact living cells provide an innovative view for solar hydrogen production. However, typical whole-cell biohybrid systems often suffer from sluggish electron transfer kinetics during transmembrane diffusion, which severely limits the efficiency of solar hydrogen production. Here, a unique biohybrid system with a quantum yield of 8.42% was constructed by feeding bismuth-doped carbon dots (Bi@CDS) to Escherichia coli (E.coli). In this biohybrid system, Bi@CDS can enter the cells and transfer the electrons upon light irradiation, greatly reducing the energy loss and shortening the distance of electron transfer. More importantly, the photocatalytic hydrogen production of the E.coli-Bi@CDs biohybrid system reached up to 0.95 mmol within 3 h under light irradiation (420-780 nm, 2000 W m-2), which is 1.36 and 2.38 times higher than that in the E.coli-CDs biohybrid system and the E.coli system, respectively. In addition, the mechanism of enhanced hydrogen production was further explored. It was found that the accelerated decomposition of glucose, the accelerated production of pyruvate, the inhibition of lactic acid, and the increase of formic acid were the reasons for the increase of hydrogen production. This work provides a novel strategy for improving the hydrogen production in photosynthetic inorganic biohybrid systems.

N vacancy and self-enhancement induced high anodic electrochemiluminescence of 3D g-C3N4 for sensitive staphylococcus aureus analysis

Here, 3D g-C3N4 with dense N vacancy in its 3D porous interconnected open-framework was synthesized, and the co-reactive 3-(dibutylamino)propylamine (DBAPA) was further covalently coupled onto the surface, resulting in a strong self-enhanced anodic electrochemiluminescence (ECL). Through introduction of high-density N vacancy, for the obtained 3D g–C3N4–NV, the band gap was broadened and the electrical conductivity was enhanced, realizing an obvious ECL improvement. Moreover, after the covalent binding of co-reactive DBAPA, the obtained 3D g–C3N4–NV-DBAPA exhibited a more intensive self-enhanced ECL signal due to the higher co-reaction efficiency originated from shorter electron transfer distance and lower energy loss. Based on the high initial signal of the proposed 3D g–C3N4–NV-DBAPA, a sensitive ECL biosensor with signal “on-off” was fabricated in assistance with multiple horizontal ordered hybridization chain reaction (HO-HCR). Through orderly fixing the reacted DNA chains on the Y-shape DNA structure on the electrode could effectively decrease diffusion process and improve the reaction efficiency of HCR process, resulting in the formation of numerous long horizontal double-strand DNA that could immobilize abundant ferrocene-doxorubicin (Fc-Dox) with ECL quenching effect. Meanwhile, compared to the traditional vertical HCR, the HO-HCR could make the quench reagent closer to the ECL emitter on the electrode surface and obtain a more effective quenching effect to enhance the sensing sensitivity. As a result, the proposed ECL biosensor archived the sensitive measurement of staphylococcus aureus with a detection limit of 10.3 aM.

Highly efficient electrochemiluminescence based on Lu@Ov-ZMO as an ECL emitter for ultrasensitive detection of CA242

An effective electrochemiluminescence (ECL) emitter, luminol@oxygen vacancies-ZnMn2O4 (Lu@Ov-ZMO), was prepared to fabricate a novel luminol/H2O2-O2/Ov-ZMO ECL system for ultrasensitive detection of carbohydrate antigen 242 (CA242). The integrated design of co-reaction accelerator ZMO and luminol effectively shortened the electron transfer distance in the ECL system. Meanwhile, the abundant oxygen vacancies in ZMO further promoted the generation of more superoxide anion radicals (O2.-), which further improved the ECL luminescence efficiency. The resonance energy transfer (RET) strategy was used to construct the signal-off ECL immunesensor with PDA@SiO2 as the quencher. The fabricated immunosensor showed a good linear range of 0.01 mU/mL to 100 U/mL with a detection limit of 3.3 μU/mL (S/N = 3) under the optimum experimental conditions. This work put forward a new method of integrating luminophore and OVs enriched accelerator with wonderful signal-amplification strategy to formulate a functional immunosensor for early disease diagnostics.

Facilitating Se(VI) adsorption and electron transfer by introducing αFeOOH to sulfidated zero-valent iron

Sulfidation of zerovalent iron (SZVI) enhances electron transfer ability due to the formation of FeSx, which facilitates pollutant removal. However, for pollutants that are difficult to adsorb onto SZVI, the longer electron transfer distance results in inefficient removal. The presence of iron (hydr)oxides on ZVI and SZVI is inevitable, and it can adsorb highly mobile pollutants (such as Se(VI)). Here, we regulated the composition of iron (hydr)oxides on ZVI and SZVI surfaces by aging treatment, which improves their Se(VI) removal performance. Based on this, αFeOOH which has a strong affinity for Se(VI), is introduced onto SZVI to synthesize the high-quality composite SZVI-αFeOOH. The characterization results showed that Fe-OH from αFeOOH and FeSx successfully combined and uniformly distributed on SZVI-αFeOOH, creating active sites, and the Se(VI) removal rate (kobs = 0.2211 min−1) increased ∼ 7.4 times over SZVI (kobs = 0.0297 min−1). The adsorption and reduction of Se(VI) were optimized by regulating the mass ratio of αFeOOH to SZVI. In addition, different initial Se(VI) concentrations and solution pH were designed to explore the effects on Se(VI) removal and evaluate the best removal reaction condition. The mechanism of Se(VI) removal by SZVI-αFeOOH is as follows: Se(VI) is firstly adsorbed on αFeOOH, which shortens the electron transfer distance, and then the absorbed Se(VI) is reduced to readily immobilized states by SZVI. This work proposes a targeted strategy to modify SZVI to efficiently remove pollutants with strong mobile and difficult adsorption.

Coupled Poly(ethylenimine) Coreactant to Enhance Electrochemiluminescence of Polymer Dots for Array Imaging of Protein Biomarkers.

Traditional electrochemiluminescent (ECL) bioanalysis suffers from the demand for excessive external coreactants and the damage of reaction intermediates. In this work, a poly(ethylenimine) (PEI)-coupled ECL emitter was proposed by covalently coupling tertiary amine-rich PEI to polymer dots (Pdots). The coupled PEI might act as a highly efficient coreactant to enhance the ECL emission of Pdots through intramolecular electron transfer, reducing the electron transfer distance between emitter and coreactant intermediates and avoiding the disadvantages of traditional ECL systems. Through modification of the PEI-Pdots with tDNA, a sequence partially complementary to cDNA that was complementary to the aptamer of target protein biomarker (aDNA), tDNA-PEI-Pdots were obtained. The biosensors were produced using Au/indium tin oxide (ITO) with an aDNA/cDNA hybrid, and an ECL imaging biosensor array was constructed for ultrasensitive detection of protein biomarkers. Using vascular endothelial growth factor 165 (VEGF165) as a protein model, the proposed ECL imaging method containing two simple incubations with target samples and then tDNA-PEI-Pdots showed a detectable range of 1 pg mL-1 to 100 ng mL-1 and a detection limit of 0.71 pg mL-1, as well as excellent performance such as low toxicity, high sensitivity, excellent selectivity, good accuracy, and acceptable fabrication reproducibility. The PEI-coupled Pdots provide a new avenue for the design of ECL emitters and the application of ECL imaging in disease biomarker detection.

Directional and rapid electron transfer in perylene diimide modified iron-manganese bimetallic metal-organic frameworks for enhanced photo-Fenton process

Bimetallic metal-organic frameworks (MOFs) with iron and another transition metal in the inorganic nodes, as newly developed photo-Fenton catalysts, have gained an ample attention because of the synergistic effect and enhanced properties compared to the monometallic counterparts. However, the photo-Fenton application of bimetallic MOFs still faces the obstacle of unsatisfactory photogenerated electrons transfer due to the fast recombination of photogenerated electron-hole pairs. In this work, perylene diimide (PDI) was modified upon bimetallic NH2-MIL-88B(Fe, Mn) (FM88B) via the ammonolysis process to construct PDI/FM88B heterojunction structure. The constructed heterostructure mediated the directional transfer of photogenerated electrons from PDI (electron donor) to FM88 (electron acceptor). The built-in electric field (BIEF) between PDI and FM88B promoted the separation and directional transfer of photogenerated electron-hole pairs. The interfacial amide bond as the high-speed electronic transmission channel reduced the transfer distance and energy barrier of photogenerated electrons from PDI to FM88B, accelerating the photogenerated electrons delivery. As a result, both Fe(III)/Fe(II) and Mn(III)/Mn(II) redox couples were continuously and rapidly cycled, ultimately boosting the performance of FM88B for H2O2 activation. Compared with FM88B, the optimal 6%PDI/FM88B exhibited excellent degradation performance against tetracycline (TC) (degradation efficiency and apparent rate constant, as 89% and 0.067 min−1) and notable synergy between photocatalysis and Fenton-like process (synergistic factor of 77.61%). DFT calculation and HPLC-MS analysis were used to verify the possible degradation pathways of TC. Meanwhile, the corresponding toxicity changes during TC degradation were studied in detail. This work paves the way for improving the heterogeneous photo-Fenton performance of the bimetallic MOFs in environmental remediation.

Preparation of lithium iron phosphate battery by 3D printing

Three-dimensional (3D) printed batteries are considered a special class of energy storage devices that allow flexible control of the electrode structure on a microscopic scale, which is crucial to improving the energy density of miniaturized devices. In this study, lithium iron phosphate (LFP) porous electrodes were prepared by 3D printing technology. The results showed that with the increase of LFP content from 20 wt% to 60 wt%, the apparent viscosity of printing slurry at the same shear rate gradually increased, and the yield stress rose from 203 Pa to 1187 Pa. The rheological property and printability of the slurry show that the printing slurry of 40 wt% LFP has excellent conformal property and self-supporting property. Due to the porous skeleton shortening the transfer distance of ions and electrons and enhancing the efficiency of the electrode reaction, the rate performances and cycle stability of LFP batteries were improved. The 3D-printed battery containing an active material loading of 15.9 mg cm−2 achieved a specific capacity of 121.7 mA h g−1 at 0.5C after 200 cycles and coulombic efficiency higher than 99.7 %, and the LFP battery had an energy density of 350 W h kg−1. These results suggest that 3D printing is an effective strategy for developing batteries with high active material loadings and energy densities at micro sizes.

Redox potentials elucidate the electron transfer pathway of NAD+-dependent formate dehydrogenases

Metal-dependent, nicotine adenine dinucleotide (NAD+)-dependent formate dehydrogenases (FDHs) are complex metalloenzymes coupling biochemical transformations through intricate electron transfer pathways. Rhodobacter capsulatus FDH is a model enzyme for understanding coupled catalysis, in that reversible CO2 reduction and formate oxidation are linked to a flavin mononuclotide (FMN)-bound diaphorase module via seven iron-sulfur (FeS) clusters as a dimer of heterotetramers. Catalysis occurs at a bis-metal-binding pterin (Mo) binding two molybdopterin guanine dinucleotides (bis-MGD), a protein-based Cys residue and a participatory sulfido ligand. Insights regarding the proposed electron transfer mechanism between the bis-MGD and the FMN have been complicated by the discovery that an alternative pathway might occur via intersubunit electron transfer between two [4Fe4S] clusters within electron transfer distance. To clarify this difference, the redox potentials of the bis-MGD and the FeS clusters were determined via redox titration by EPR spectroscopy. Redox potentials for the bis-MGD cofactor and five of the seven FeS clusters could be assigned. Furthermore, substitution of the active site residue Lys295 with Ala resulted in altered enzyme kinetics, primarily due to a more negative redox potential of the A1 [4Fe4S] cluster. Finally, characterization of the monomeric FdsGBAD heterotetramer exhibited slightly decreased formate oxidation activity and similar iron-sulfur clusters reduced relative to the dimeric heterotetramer. Comparison of the measured redox potentials relative to structurally defined FeS clusters support a mechanism by which electron transfer occurs within a heterotetrameric unit, with the interfacial [4Fe4S] cluster serving as a structural component toward the integrity of the heterodimeric structure to drive efficient catalysis.

Growth mechanism of 2D heterostructures of polypyrrole grown on TiO2 nanoribbons for high-performance supercapacitors.

The patterning of functional structures is crucial in the field of materials science. Despite the enticing nature of two-dimensional surfaces, the task of directly modeling them with regular structures remains a significant challenge. Here we present a novel method to pattern a two-dimensional polymer in a controlled way assisted by chemical polymerization, which is confirmed through discernible observation. The fabrication process involves in situ polymerization to create 2D layers of polypyrrole (PPy) on extended 2D TiO2 nanoribbons, resulting in oriented arrays known as 2D PPy/TiO2. These arrays exhibit enhanced electrochemical performance, making them ideal for supercapacitor applications. The skeleton structure of this material is distinctive, characterized by a homogeneous distribution of layers containing various elements. Additionally, it possesses a large contact surface, which effectively reduces the distance for ion transport and electron transfer. The 2D PPy/TiO2 electrode has a maximum specific capacitance of 280 F g-1 at an applied current density of 0.5 A g-1. Moreover, it demonstrates excellent rate capability and cycling stability. Therefore, this approach will open an avenue for improving polymerization-based patterning toward recommended applications.

N-Doped Carbon Nanowire-Modified Macroporous Carbon Foam Microbial Fuel Cell Anode: Enrichment of Exoelectrogens and Enhancement of Extracellular Electron Transfer.

Microbial fuel cell (MFC) performance is affected by the metabolic activity of bacteria and the extracellular electron transfer (EET) process. The deficiency of nanostructures on macroporous anode obstructs the enrichment of exoelectrogens and the EET. Herein, a N-doped carbon nanowire-modified macroporous carbon foam was prepared and served as an anode in MFCs. The anode has a hierarchical porous structure, which can solve the problem of biofilm blockage, ensure mass transport, favor exoelectrogen enrichment, and enhance the metabolic activity of bacteria. The microscopic morphology, spectroscopy, and electrochemical characterization of the anode confirm that carbon nanowires can penetrate biofilm, decrease charge resistance, and enhance long-distance electron transfer efficiency. In addition, pyrrolic N can effectively reduce the binding energy and electron transfer distance of bacterial outer membrane hemin. With this hierarchical anode, a maximum power density of 5.32 W/m3 was obtained, about 2.5-fold that of bare carbon cloth. The one-dimensional nanomaterial-modified macroporous anodes in this study are a promising strategy to improve the exoelectrogen enrichment and EET for MFCs.