Enhanced Electron Transfer Research Articles

Mn─O Covalency as a Lever for Na⁺ Intercalation Kinetics: The Role of Oxygen Edge-Sharing Co Octahedral Sites in MnO₂.

The strategic enhancement of manganese-oxygen (Mn─O) covalency is a promising approach to improve the intercalation kinetics of sodium ions (Na⁺) in manganese dioxide (MnO2). In this study, an augmenting Mn─O covalency in MnO2 by strategically incorporating cobalt at oxygen edge-sharing Co octahedral sites is focused on. Both experimental results and density functional theory (DFT) calculations reveal an increased electron polarization from oxygen to manganese, surpassing that directed toward cobalt, thereby facilitating enhanced electron transfer and strengthening covalency. The synthesized Co-MnO2 material exhibits outstanding electrochemical performance, demonstrating a superior specific capacitance of 388Fg-1 at 1Ag-1 and maintaining 97.21% capacity retention after 12000 cycles. Additionally, an asymmetric supercapacitor constructed using Co-MnO2 achieved a high energy density of 35Whkg-1 at a power density of 1000Wkg-1, underscoring the efficacy of this material in practical applications. This work highlights the critical role of transition metal-oxygen interactions in optimizing electrode materials and introduces a robust approach to enhance the functional properties of manganese oxides, thereby advancing high-performance energy storage technologies.

Multifunctional Ni-MOF (3D) with N-rich structures for self-generated reactive oxygen species and enhanced electron transfer for synergistic degradation of organic pollutants and removal of Hg(II)

Metal–organic frameworks (MOFs) can effectively adsorb or remove pollutants; however, their application to water treatment remains limited. Herein, we report the preparation of two novel multifunctional Ni-based MOFs (2D and 3D), via the design and synthesis of multi-nitrogen-like ligands. The introduction of polynitrogen-containing organic macrocyclic ligands improved the structure and electron transfer capability of the MOF, and its adsorption and synergistic degradation performance were further enhanced via coordination with Ni. The 3D MOF (MOF-2) had a maximum adsorption capacity of 948 mg/g for Hg(II). The adsorption and synergistic degradation capacities of MOF-2 for tetracycline (TC, 18 mg/L), 17α-ethynylestradiol (EE2, 3 mg/L), rhodamine B (RhB, 6 mg/L), and methylene blue (MB, 6 mg/L) were 98.54%, 97.32%, 91.08%, and 85.02%, respectively. The addition of KHSO5 (PMS, 0.01 g/L) resulted in nearly 100% degradation of the organic pollutants within 100 min. MOF-2 alone simultaneously degraded more than 90.73% (360 min Hg(II) adsorption equilibrium) of five pollutants in ultrapure water, tap water, and lake water. MOF-2+PMS degraded 99.13% of TC within 60 min, and the remaining four pollutants were completely adsorbed and degraded. DFT calculations and experiments indicated that the efficient adsorption of Hg(II) and efficient degradation of the organic pollutants by MOF-2 were mainly attributed to its abundant N atoms, which provide active sites for Hg(II) capture; and the structure itself has strong electron transfer ability and self-produced reactive oxygen species (ROS), which can effectively degrade organic pollutants and activate PMS to enhance the degradation efficiency. MOF-2 also exhibited 100% antibacterial activity against Escherichia coli and Staphylococcus aureus. This work provides a basis for designing synthesis pathways for MOFs and elucidates the electron-transfer mechanism underlying the enhanced synergistic removal of complex pollutants from water.

Metal Organic Frameworks‐Derived NiO/NiCo2O4 Heterostructures for Effective Methanol Oxidation Reaction

AbstractThe electrochemical process of methanol oxidation reaction (MOR), which is closely associated with electrochemical production of formate and hydrogen, is considered a highly viable avenue for advancing renewable energy technologies. Nevertheless, the development and creation of affordable, effective, and durable electrocatalysts for MOR continue to present significant obstacles. In this study, a hierarchical porous NiO/NiCo2O4/NF electrode is fabricated through the integration of solvothermal and thermal oxidation treatments of Ni‐MOF‐74 and NiCo‐Asp. After thoroughly assessing the electrochemical performance for MOR, NiO/NiCo2O4/NF demonstrates a significant current density of 140 mA cm−2 at 1.6 V (vs. RHE) and a tafel slop of 45.0 mV·dec−1 in 1 M KOH and 0.5 M methanol. The excellent performance of MOR can be ascribed to the hierarchical porous nature that enhances mass and electron transport while offering numerous active sites for electrocatalytic reactions. Additionally, the hetero interface between NiO and NiCo2O4 could further enhance electron transfer rate and reaction kinetics for the MOR. The developed NiO/NiCo2O4/NF electrode shows potential as a viable and economical alternative to Pt‐based electrocatalysts for MOR‐based applications.

Multilayer Porous Fe/Co-N-MWCNT Electrocatalyst For Rechargeable Zinc-Air Batteries.

The design of efficient, stable, low-cost non-precious metal-based electrocatalysts with enhanced oxygen reduction reaction (ORR) activity has garnered significant attention in the scientific community. This study introduces a novel electrocatalyst, Fe/Co-N-MWCNT, synthesized through the in-situ growth of ZIF-8 and Fe/Co-Phen on multi-walled carbon nanotubes (MWCNTs), followed by pyrolysis at varying temperatures to optimize its properties. The inclusion of Fe and Co during the pyrolysis process facilitated the creation of metal active sites and Fe-Co, enhancing electron transfer and ORR activity. Compared to Pt/C (E1/2=0.854 V, JL=4.90 mA cm-2), Fe/Co-N-MWCNT exhibited a similar half-wave potential (E1/2=0.812 V) and an improved limiting current density (JL=5.37 mA cm-2). Moreover, Fe/Co-N-MWCNT displayed remarkable stability, showing only a 7 mV negative shift in E1/2 after 2000 cycles. Ampere response testing indicated a current decay of only 7.8 % for Fe/Co-N-MWCNT after 10000 s, while Pt/C experienced a decay of about 18.4 %. The exceptional catalytic stability of Fe/Co-N-MWCNT positions it as a promising candidate for rechargeable zinc-air batteries, attributed to its high pyridinic nitrogen content, unique structure, and abundant metal active sites.

Accelerated Electrons Transfer and Synergistic Interplay of Co and Ge Atoms (111 Crystal Plane) Activated by Anchoring Nano Spinel Structure Co2GeO4 onto Carbon Cloth Composite Electrocatalyst for Highly Enhanced Hydrogen Evolution Reaction

The electrochemical hydrogen evolution reaction (HER) was considered to be a promising strategy for future clean energy. In this work, a composite electrocatalyst (designated as CGO36@CC) was synthesized through anchoring of nano spinel structure Co2GeO4 onto carbon cloth fibers and exhibited outstanding electrocatalytic performance for HERs in an alkaline medium. The characterization outcome established that, after 36 h of hydrothermal reaction, nano spinel structure Co2GeO4 particles (exposed abundant 111 crystal planes) were stably loaded onto a carbon cloth fiber surface, and this structural configuration facilitated the electrons transferring between each other. In addition, the electrochemical analysis revealed that the incorporation of nano spinel structure Co2GeO4 and carbon cloth significantly augmented the electrochemical activity value of the composite and efficiently enhanced the HER performance. Notably, the overpotential was merely 96 mV at 10 mA·cm−2 current density, and the Tafel slope was only 48.9 mV·dec−1. Moreover, CGO36@CC displayed remarkable catalytic activity and sustained HER catalytic stability. The theoretical catalytic prowess of CGO36@CC stemmed from the collaborative influence of germanium and cobalt atoms within the exposed 111 crystal plane of the Co2GeO4 molecular framework. The amalgamation of Co2GeO4 with carbon cloth fiber conferred upon the composite electrocatalyst both superior theoretical catalytic activity and enhanced electron transfer capability. This work provides a novel strategy for exploring a highly efficient composite electrocatalyst combined transition metal with carbon material to accelerate the HER activity.

Built-In Electric Field Boost Photocatalytic Degradation of Pollutants in Wastewater.

The photocatalysis technique shows significant potential for wastewater degradation; however, the rapid recombination of photogenerated holes and electrons severely limits its photocatalytic efficiency. This situation necessitates the development of effective strategies to tackle these challenges. One well-documented approach is built-in electric field engineering in heterojunctions or composites, which has been shown to enhance electron transfer and thereby reduce the recombination of electrons and holes. This strategy has proven highly effective in significantly improving photocatalytic activity for the degradation of pollutants in wastewater. In this context, we summarize recent advancements in built-in electric field engineering in photocatalysts, highlighting the fundamentals and modifications of this approach, as well as its positive impact on photocatalytic performance in the degradation of wastewater pollutants.

Mn and P co-doped biochar catalyst for persulfate efficient degradation of tetracycline hydrochloride：Process and mechanism

A novel manganese/phosphorus-doped biochar (Mn/P-C) catalyst was prepared for the degradation of tetracycline hydrochloride (TCH) by activating peroxymonosulfate (PMS). Characterization of the catalyst revealed that Mn/P-C possessed stacked, complex pleated sheets and surface oxygen-containing functional groups, providing abundant active sites. Mn/P-C exhibited superior adsorption and catalytic properties. Nearly complete removal of TCH was achieved under optimal conditions: a PMS concentration of 2 mM, pH 6.51, and catalyst dosage of 0.5 g/L within 120 minutes of reaction time. The reaction rate constant of the system was 0.060 min−1, which was 13.79 times higher than that of pure biochar. XPS characterization before and after the reaction, quenching experiment, and electron paramagnetic resonance (EPR) experiment comprehensively verified the reaction pathway mechanisms. The primary radicals involved were SO4•- and O2•-, while the 1O2 non-radical transfer pathway was also generated on the catalyst surface, enhancing electron transfer and accelerating catalytic degradation. UPLC-MS/MS was used to investigate the main degradation intermediates and the possible transformation pathways were proposed. The toxicity of TCH and its intermediates was evaluated by the quantitative structure-activity relationship (QSAR) method. Theoretical calculations provided deeper insights into TCH degradation pathways through DFT computational analysis. This study confirms that doping biochar with transition metals and nonmetals can synergistically enhance the degradation efficacy of PMS-activated biochar catalysts, providing a novel approach for the application of carbon-based material catalysts in persulfate activation.

Hydrogen-bond enhanced interior charge transport and trapping in all-fiber triboelectric nanogenerators for human motion sensing and communication

Maximizing charge density output within confined tribolayer areas is crucial for advancing triboelectric nanogenerator (TENG) performance. While conventional methods primarily focus on enhancing current density by modifying the surface properties of tribo-surfaces, the impact of dipole-dipole interactions between polymer molecular chains in the fibrous tribomaterials has been underexplored. This study reveals that intermolecular dipole-dipole interactions, mediated by hydrogen bonding between chitosan and nylon66 molecular chains, serve as effective bridging mechanisms that substantially boost TENG current density. Furthermore, we developed a breathable and antibacterial electrode by depositing silver nanowires (AgNWs) on the tribolayer surfaces. To prevent air breakdown resulting from excessively high current density, multiwalled carbon nanotubes (MWCNTs) were integrated to enhance electron transfer and storage. The structure we constructed achieved an optimized performance with a high voltage of 335 V, current density of 194.5 mA m−2 and power density of 65.1 W m−2, which demonstrates outstanding performance compared to previously obtained results. Finally, the prepared SWS-TENG was attached to the fingertips, wrist, and neck to track the physiological signals of the human state during standing, walking, and running. In addition, the integration of Morse code functionality introduces new possibilities for healthcare, particularly for non-verbal patients, enabling non-invasive communication of symptoms and emotions. This technology demonstrates significant potential as a versatile and non-invasive tool for point-of-care (PoC) and biomedical applications when deployed on various parts of the human body.

Integrating NiSe2-MoSe2 heterojunctions with N-doped porous carbon substrate architecture for an enhanced electrocatalytic water splitting device

The development of sustainable energy technologies relies on the exploitation of efficient and durable electrocatalysts for water splitting at high current densities. Our work presents a novel bifunctional catalyst, denoted as NM@NC/CC, which combines the benefits of NiSe2-MoSe2 heterojunctions with nitrogen-enriched porous carbon derived from metal-organic frameworks (MOFs). The integration of these components is designed to harness their combined advantages, which include enhanced electron transfer, improved mass and gas evolution dynamics, and an increased number of catalytically active sites. These features collectively optimize the energetics for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a result, the catalyst facilitates rapid kinetics for the overall water-splitting process. The NM@NC/CC demonstrates low overpotentials, requiring only 91 mV for the HER and 280 mV for the OER to reach a current density of 10 mA cm−2. Even at higher current densities of 100 mA cm−2 for HER and 50 mA cm−2 for OER, the overpotentials are only 159 mV and 350 mV, respectively. Additionally, a two-electrode setup using this catalyst achieves a current density of 10 mA cm−2 with a minimal cell voltage of 1.56 V. The insights gained from this study will contribute to the advancement of electrocatalysts for energy conversion technologies.

Zn-O-Sn covalency interface governs the intrinsic activity of the Zn2SnO4/SnO2 heterostructure for boosting hydrogen peroxide production

Electrocatalytic production of hydrogen peroxide (H2O2) from oxygen is vital for sustainable clean fuel. Developing highly active, stable, and inexpensive catalysts for H2O2 remains a top priority but is still challenging. In this study, an atomic-shared heterointerface was constructed between Zn2SnO4 and SnO2 via a self-templating co-precipitation method. Theoretical and experimental analysis confirms the delocalization effects of electrons within the Zn2SnO4/SnO2 spinel structure. The resulting Zn-O-Sn bridge (asymmetric sites) modulates electronic transport at the interface, and the intensified Zn-O bond facilitates proton adsorption and transfer kinetics. Moreover, strong interface coupling between Zn2SnO4 and SnO2 enhances electron transfer, which effectively promotes the *OOH intermediate favorable for H2O2 production, boosting H2O2 selectivity of nearly 97 %. The high production rate of 8.19 mol gcat−1 h−1 and excellent stability during long-term operation over 24 h. This work provides strategic insights into developing efficient H2O2 catalysts and other catalytic applications.

Synergistic role of carbon quantum dots on biohydrogen production

Biohybrid system has their distinct ability to improve microbial fermentation. This study demonstrates the role of surface-doped carbon quantum dots (CQDs) on dark fermentative biohydrogen production using lactobacillus organic-hybrid biocatalyst. Herein, nitrogen-doped carbon quantum dots (N-CQDs) with < 5 nm (having a surface charge of +2.6 mV) and un-doped carbon quantum dots (CQDs) (having a surface charge of −4.5 mV) were synthesized via chemical assisted process. Subsequently, the biohybrid systems were constructed via augmentation of N-CQDs and CQDs with Lactobacillus delbreuckii and assessed for biohydrogen production. The results revealed that both the biohybrid systems (N-CQDs- Lactobacillus delbreuckii and CQDs- Lactobacillus delbreuckii) provided improved hydrogen production than that of the native bacterial strain. Interestingly, the obtained N-CQDs- Lactobacillus delbreuckii system provided the maximum hydrogen yield of 2.01 mol/mol hexose, followed by 1.86 mol/mol hexose from CQDs- Lactobacillus delbreuckii, which is about 33 % and 19 % higher than the bare bacterial strain. The electron transfer and metabolic alteration of microbes by carbon quantum dots were assessed using cyclic voltammetry (CV) and VFA production. It was concluded that the improved bio-hydrogen production from N-CQDs- Lactobacillus delbreuckii is attributed to enhanced electron transfer, which regulates the central metabolic pathway of acetate and butyrate synthesis with the least production of lactate and other reduced end product formation.

Dual polarization in CoMoO4-NiMoO4 heterojunction boosted electrochemical charge storage

Binary transition metal oxides (BTMOs) stand out as a focal point due to their distinctive electrochemical properties. However, they encounter challenges like low conductivity and limited active sites. To tackle these obstacles, we have meticulously designed a CoMoO4-NiMoO4 (CMNM) heterostructure featuring significant compressive-tensile strain. This design facilitates the robust integration of CoMoO4 (CM) and NiMoO4 (NM), initiating interfacial polarization, and establishing a built-in electric field (BIEF) that significantly enhances electron transfer between the phases. Moreover, the strain serves as a driving force for the electric field, promoting the rearrangement of interface electrons and further boosting interfacial polarization. This avant-garde approach propels the CMNM electrode to achieve a remarkable specific capacity of 530.45 C g−1 at 1 A g−1, maintaining 327 C g−1 even at 10 A g−1, thus showcasing a superior rate capability. Furthermore, an asymmetric supercapacitor employing CMNM as the positive and FeOOH as the negative achieves a high energy density of 78.9 Wh kg−1 at a power density of 927.02 W kg−1. Our methodology, leveraging heterostructures coupled with the interfacial strain tactics, paves a novel avenue for high-performance supercapacitors.

Construction of "Metal Defect/Oxygen Defect Junction" in ZnFe2O4-NiCo2O4 Heterostructures for Enhancing Electrocatalytic Oxygen Evolution.

Defect engineering is a promising approach to improve the conductivity and increase the active sites of transition metal oxides used as catalysts for the oxygen evolution reaction (OER). However, when metal defects and oxygen defects coexist closely within the same crystal, their compensating charges can diminish the benefits of both defect structures on the catalyst's local electronic structure. To address this limitation, a novel strategy that employs the heterostructure interface of ZnFe2O4-NiCo2O4 to spatially separate the metal defects from the oxygen defects is proposed. This configuration positions the two types of defects on opposite sides of the heterojunction interface, creating a unique structure termed the "metal-defect/oxygen-defect junction". Physical characterization and simulations reveal that this configuration enhances electron transfer at the heterostructure interface, increases the oxidation state of Fe on the catalyst surface, and boosts bulk charge carrier concentration. These improvements enhance active site performance, facilitating hydroxyl adsorption and deprotonation, thereby reducing the overpotential required for the OER.

In Situ Label‐Free Monitoring of Riboflavin Concentration in Shewanella via a Fiber‐Optic Biosensor Modified by Ti3C2‐MXene@ SGNps Composites

AbstractRiboflavin is a common marker of microbial corrosion and can act as an electron shuttle in the solvated state to enhance electron transfer efficiency. In this paper, an in‐situ label‐free fiber‐optic biosensor modified by Ti3C2‐MXene@Square Gold nanoparticles (SGNps) composites and riboflavin kinase is developed, which behaved with high sensitivity for measuring riboflavin. The sensing interface of the sensor is constructed by stepwise assembly of SGNps and riboflavin kinase using Ti3C2‐MXene nanosheets as the supporting substrate. Riboflavin kinase catalyzed the phosphorylation of riboflavin to form flavin mononucleotides in the presence of adenine nucleoside triphosphate and Mg2+. Experimental results showed that the sensitivity of riboflavin measurement is 5.61 nm µm−1 and the limit of detection (LOD) is 115 nmol L−1 (nm) in the concentration range of 0–2.656 µm. In situ label‐free monitoring of riboflavin in Shewanella, the sensitivity of the sensor in bacterial fragmentation fluid is 53.90 nm/OD within the optical density (OD) of 0–0.175, and the LOD is OD = 0.017. The above results verified the feasibility of the sensor for in situ monitoring of riboflavin in microbial corrosive environments, with ultra‐low detection limit and good selectivity, which undoubtedly provided great research value for the application of optical fiber sensors in microbial corrosion monitoring.

Unusually improved peracetic acid activation for ultrafast organic compound removal through redox-inert Mg incorporation into active Co3O4

Peracetic acid (PAA) is increasingly used in advanced oxidation processes (AOPs) for water purification, yet there remains a critical need for highly-efficient and low-cost activators. Here, we constructed abundant oxygen vacancies (OVs) into redox-active Co3O4 by incorporating redox-inert Mg species (MgCoOx), achieving ultrafast degradation of sulfamethoxazole (SMX) via PAA activation. The MgCoOx/PAA system successfully degraded SMX within 3 min, with a removal rate 154.8 times higher than the Co3O4/PAA system, surpassing even previously reported single-atom catalysts. The primary active species identified was the acetylperoxyl radical (CH3C(O)OO•), with CoIV-oxo acting as a secondary active species that produced 18O-labeled sulfone compounds. We proposed a novel mechanism involving redox-inert Mg species that simultaneously strengthened PAA adsorption and activation. The enriched surface hydroxyl groups after Mg incorporation elevated the affinity for PAA binding. Meanwhile, the reduced Co average valence state and enhanced electron transfer capability facilitated PAA activation. This study offers an in-depth knowledge of redox-inert alkaline earth metals in PAA-AOPs.

Enhanced marmatite activation by copper with ammonium sulfate: An experimental and DFT investigation

The presence of iron atoms on the marmatite surface hinders effective interaction between the activator and the mineral, leading to unsatisfactory flotation performance through direct copper (Cu) activation. Hence, this study introduced ammonium sulfate to enhance the marmatite-activation capability by Cu ions. Additionally, the reinforcement mechanism was investigated through microflotation tests, atomic force microscopy (AFM), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and density-functional theory (DFT) calculations. Microflotation results demonstrated that the addition of ammonium sulfate as a complexing reagent increased the flotation recovery of marmatite by 17.36%. AFM analysis revealed that marmatite subjected to enhanced activation (i.e., in the presence of ammonium sulfate) exhibited a considerably higher surface roughness than that subjected to direct Cu activation. Moreover, the average height of hill-shaped materials on the marmatite surface notably increased to 9.6 nm after enhanced Cu activation. SEM-EDS analysis revealed that the concentration of Cu atoms (2.2%) on the marmatite surface after enhanced Cu activation was nearly three times that (0.8%) after direct Cu activation. Additionally, XPS results indicated a considerably higher presence of the Cu–S component on the marmatite surface after enhanced Cu activation than after direct Cu activation. ToF-SIMS analysis indicated an increase in the fragment peaks of Cu+, CuOCS2+, OCS2−, and OC2H2S2− on the surface of enhanced-activated marmatite. Additionally, DFT calculations indicated that the presence of NH3 molecules enhanced electron transfer between Cu and S on the hydrated marmatite surface. The marmatite (1 1 0) surface exhibited more negative adsorption energy of Cu ions after the action of NH3 molecules, and NH3–Cu showed a more stable adsorption configuration than Cu. Therefore, the addition of ammonium sulfate enhanced the Cu activation for marmatite, thereby improving flotation performance.

Solvent polarity-driven modulation of excited states: A DFT and spectroscopic analysis

The relationship between the photophysical properties of N,N,N’,N’-tetra-p-tolyl-benzidine (TTB) and [1,4-bis[2-[4-[N,N-di(p-tolyl)amino]phenyl]vinyl]benzene (DSB) molecules and solvent polarity was explored through steady-state spectroscopy, femtosecond transient absorption spectroscopy, and quantum chemical calculations. Computational results and steady-state spectra reveal that the lowest singlet excited states of TTB and DSB are primarily characterized by localized excited (LE) states in nonpolar cyclohexane (CHX), whereas intramolecular charge transfer (ICT) components predominate in highly polar acetonitrile (ACN). Compared to TTB, the excited-state potential of DSB demonstrates a heightened sensitivity to solvent polarity, exhibiting larger dipole moments due to enhanced electron transfer enabled by the incorporation of styrene groups. Ultrafast femtosecond transient absorption spectroscopy distinctly shows the transition from LE states in nonpolar CHX to ICT states in highly polar ACN. The deactivation mechanisms were further elucidated to understand how solvent polarity modulates excited states and high quantum yields, providing valuable insights for the design and application of photophysical materials.

Vacancy-rich heterogeneous MnCo2O4.5@NiS electrocatalyst for highly efficient overall water splitting

Alkaline water electrolysis is regarded as a promising technology for sustainable energy conversion. Spinel oxides have attracted considerable attention as potential catalysts because of their diverse metal valence states. However, achieving the required current densities at low voltages is a challenge due to its limited active sites and suboptimal electron transport. In this study, we present a novel bifunctional catalyst composed of MnCo2O4.5 nanoneedles grown on NiS nanosheets for water electrolysis. Remarkably, MnCo2O4.5@NiS demonstrates exceptional catalytic activity, requiring 187 and 288 mV to achieve a current density of 100 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. The impressive performance of MnCo2O4.5@NiS is demonstrated by the lower value of voltage 1.44 V needed to deliver the current density of 10 mA cm−2, which outperformed the 1.66 V required for a commercial Pt/C||RuO2 system. Detailed structure analysis and density functional theory (DFT) calculations reveal that the MnCo2O4.5@NiS heterostructure enhances electron transfer at the interface, promotes the formation of oxygen vacancies and tunes the electronic structures of Mn and Co. These findings underscore the potential of MnCo2O4.5@NiS as an efficient and cost-effective electrocatalyst for hydrogen production.

Effect of Three Different Types of Biochar on Bioelectricity Generated from Plant Microbial Fuel Cells under Unsaturated Soil Condition.

Plant microbial fuel cell (PMFC) is an emerging technology, showing promise for environmental biosensors and sustainable energy production. Despite its potential, PMFCs struggle with issues like low power output and limited drought resistance. Recent studies proposed that integrating biochar may enhance PMFC performance due to its physicochemical properties. The influence of different biochar types on PMFC efficiency has been minimally explored. This study aims to fill this gap by evaluating the performance of PMFCs integrated with various biochar types under unsaturated soil conditions. The study found that the addition of biochar types─specifically reed straw biochar (RSB), apple wood biochar (AWB), and corn straw biochar (CSB)─significantly influenced the performance of PMFCs. RSB, with its large surface area and porous structure, notably increased the current output by reducing soil resistance and enhancing electron transfer efficiency in microbial reduction reactions, achieving a peak power density of approximately 1608 mW/m2. AWB, despite its less porous structure, leveraged its high cation exchange capacity and hydrophilic functional groups to foster microbial community growth and diversity, thereby also increasing bioelectricity output. Conversely, CSB, with its large surface area, showed the least improvement in PMFC performance due to its layered structure and lower water retention capacity. Additionally, under drought conditions, PMFCs with added RSB and AWB exhibited better drought resistance due to their ability to improve soil moisture characteristics and enhance soil conductivity. The addition of biochar reduced soil resistance, increasing the bioelectric output of PMFCs and maintaining good performance even under low moisture conditions. This study highlights the critical role of biochar's surface area and functional groups in optimizing PMFC performance. It enhances our understanding of PMFC optimization and might offer a novel power generation method for the future, while also presenting a fresh strategy for soil monitoring.

Construction of biochar assisted S-scheme of CeO2/g-C3N4 with enhanced photoreduction CO2 to CO activity and selectivity

The multi-interface contacted S-scheme photocatalyst was used for CO2 reduction in this research. A hybrid nanostructures catalyst was constructed using g-C3N4 nanosheet, oxidized CeO2 nanoparticles, and biochar (BIO, cattail-derived). The g-C3N4-BIO/CeO2 catalyst exhibited high selectivity (> 95 %) in converting CO2 to CO in a gas-solid-liquid phase CO2 reduction system. Theoretical and experimental evidence suggests that the multi-interface and interfacial internal electric field (IEF) play a crucial role in enhancing electron transfer and redox ability in CO2 reduction processes. Ce4+ species in CeO2 have the capability to donate two electrons, facilitating the two-electron reduction process involved in the transformation of CO2 to CO. Additionally, Ce4+ in CeO2 acted as an electron trapping agent and could be reduced to Ce3+ ion after trapping electrons, which facilitated the separation process of photogenerated carriers inside CeO2. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) demonstrated that COOH* intermediate played a key role as the rate determining step in the overall CO2 photoreduction to CO. This investigation will contribute to the development and application of new and environmentally friendly BIO-based S-scheme photocatalysts.