Electron Transfer Channels Research Articles

A Novel Nickel and Cobalt-Layered Double Hydroxide@Nickel Borate with Three-Dimensional Flower-like Structure as Electrode Material for High-performance Hybrid Supercapacitor

It is crucial for enhancing electrochemical properties of existing supercapacitors to design and develope electrode materials with unique structures. Herein, a novel design of nickel and cobalt-layered double hydroxide@nickel borate (NiCo-LDH@Ni(BO2)2) with three-dimensional flower-like structure as the positive by a two-step method for asymmetric supercapacitor is reported. The synthesis strategy of the unique structure formed by stacking two-dimensional lamels provides efficient mesoporous networks, ion diffusion channels for quicker electron transfer, and enhances more active sites for nickel and cobalt-layered double hydroxide (NiCo-LDH) and nickel borate (Ni(BO2)2). The specific electric capacity of optimized NiCo-LDH@Ni(BO2)2 composite achieves 1373 F·g−1 at 0.5 A·g−1 in a three-electrode system. The self-assembled hybrid supercapacitors (HSC) NiCo-LDH@Ni(BO2)2//AC owns the an maximum energy density of 46.5 Wh·kg-1 at the power density 850 W·kg-1. Meanwhile, it displays significant cycle stability with an impressive capacitance retention rate of 84.9% over 5000 charging/discharging cycles. In the end, two serial-connected HSC devices can light up (Light Emitting Diodes) LEDs with difference color (red, yellow and green). Hence, the present research can match the demand of high-property electrode materials for energy storing equipment in the future.

Pr doping promotes the formation of Pt single atoms by regulating metal-support interaction for remarkable photocatalytic hydrogen production

Since the metal-support interaction (MSI) has a great influence on the structure and properties of single atom catalysts (SACs), the activity and stability of SACs can be effectively regulated by adjusting the structure of the matrix. Herein, the morphology of surface supported Pt species can be controlled by doping to adjust the properties of TiO2 support. Specifically, under the same conditions, the Pt species on the Pr doped TiO2 surface are Pt SAs (PtSA/TiO2(Pr)), while on the pure TiO2 surface are particles (PtNP/TiO2). Experimental and theoretical studies demonstrate that Pr doping weakens the interaction of Ti-O bond, stabilizes the O-Pt unit site and Pt SAs. Impressively, PtSA/TiO2(Pr) shows superior photocatalytic hydrogen production performance (196.43 mmol g-1h−1), far exceeding PtNP/TiO2 (91.96 mmol g-1h−1). Additionally, Pr dopant modulates the electronic interaction between TiO2 support and Pt SAs, thus the adsorption/desorption behavior of H intermediates (H*) is balanced. Besides, the electron delocalization of O adjacent to Pt SAs can be adjusted by Pr doping, prompting the establishment of efficient Pt-O electron transfer channels and further enhances the utilization of photogenerated carriers. This study presents a promising strategy to prepare SACs with high activity for photocatalyst hydrogen production.

A photosynthesis‐derived bionic system for sustainable biosynthesis

“Cell factory” strategy based on microbial anabolism pathways offers an intriguing alternative to relieve the dependence on fossil fuels, which are recognized as the main sources of CO2 emission. Typically, anabolism of intracellular substance in cell factory requires the consumption of sufficient reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine triphosphate (ATP). However, it is of great challenge to modify the natural limited anabolism and to increase the insufficient level of NADPH and ATP to optimum concentrations without causing metabolic imbalance. Inspired by the natural photosynthesis process in which NADPH and ATP can both be produced through the coupled electron‐proton transfer processes driven by sunlight, herein we designed a light‐driven bionic system composed of three modules including photo‐induced electron module, electron transfer channel module and proton gradient module. The proposed strategy of light‐driven bionic system enables for achieving simultaneous and controllable supplies of NADPH and ATP, thus facilitating both highly efficient CO2 fixation and biomanufacturing. The proposed light‐driven bionic system design strategy in this work might pave new sustainable ways for reducing power and energy regeneration to optimize microbial metabolism, offering intriguing alternatives for CO2 emission reduction and high value‐added chemical biomanufacturing.

A photosynthesis-derived bionic system for sustainable biosynthesis.

"Cell factory" strategy based on microbial anabolism pathways offers an intriguing alternative to relieve the dependence on fossil fuels, which are recognized as the main sources of CO2 emission. Typically, anabolism of intracellular substance in cell factory requires the consumption of sufficient reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine triphosphate (ATP). However, it is of great challenge to modify the natural limited anabolism and to increase the insufficient level of NADPH and ATP to optimum concentrations without causing metabolic imbalance. Inspired by the natural photosynthesis process in which NADPH and ATP can both be produced through the coupled electron-proton transfer processes driven by sunlight, herein we designed a light-driven bionic system composed of three modules including photo-induced electron module, electron transfer channel module and proton gradient module. The proposed strategy of light-driven bionic system enables for achieving simultaneous and controllable supplies of NADPH and ATP, thus facilitating both highly efficient CO2 fixation and biomanufacturing. The proposed light-driven bionic system design strategy in this work might pave new sustainable ways for reducing power and energy regeneration to optimize microbial metabolism, offering intriguing alternatives for CO2 emission reduction and high value-added chemical biomanufacturing.

Feδ+ diaspora titanium dioxide and graphene: A study of conductive powder materials and coating applications.

Developing new conductive primers to ensure electrostatic spraying is crucial in response to the call for lightweight production of new energy vehicles. We report a stabilized material, Fe-T/G, of Fe-doped TiO2 composite graphene synthesized by a simple hydrothermal and electrostatic self-assembly method. The resistivity decreases from 0.9165Ω·cm to 0.0943Ω·cm for T/G. XPS and EPR confirm that Fe3+ is doped into the TiO2 lattice to generate OVs, and Feδ+ is introduced to activate the surrounding Fe-Ti active sites to break the obstruction of the Ti-O bond and build the Ti-O-C and Feδ+-O-C bonds between TiO2 and graphene to connect the two tightly. Multiple electron transfer channels promote Feδ+ impurity energy levels in the TiO2 valence and conduction bands to build electron leaping pathways, enhancing the electron transport ability. Based on this, Fe-T/G can be used as a conductive coating material to develop various insulator surfaces. With Fe-T/G powder material and PVDF, a conductive primer coating can be made and overlaid on a plastic plate to simulate actual applications. The resistance can still be maintained below 25Ω·cm. Through contact angle experiments, it has been confirmed that the superhydrophobic surface has a water contact angle of 142.8°, with self-cleaning potential.

Porous Supramolecular Crystalline Materials for Photocatalysis.

Porous supramolecular crystalline materials (PSCMs), usually including hydrogen-bonded organic frameworks (HOFs), π frameworks, and so on, can be defined as a type of porous supramolecular assemblies stabilized by hydrogen-bonding, π-π stacking and other non-covalent interactions. Given the unique features of mild synthetic conditions, well-defined and tailorable structures, easy healing and regeneration, PSCMs have captured widespread interest in molecular recognition, sensor, gas storage and separation, and so on. Moreover, they currently emerge as promising photocatalysts because it is readily to endow PSCMs with photo-function, and the hydrogen-bonding and π-π stacking can serve as electron transfer channels to boost photocatalytic activity. Nevertheless, the research on PSCMs for photocatalysis is still at an early stage. A review on this topic will greatly promote the development of supramolecular chemistry. In this Minireview, we will firstly introduce the syntheses of PSCMs, and then highlight the advantages of PSCMs in photocatalysis. Following this, we will further summarize the photocatalytic applications of PSCMs toward CO2 reduction, H2 evolution, H2O2 production, organic transformation and pollution degradation, where emphasis will be placed on concluding the relationship between the catalyst performances and structures. Finally, we will discuss the remaining challenges and perspectives in developing high-performance PSCM-based photocatalysts.

Increasing Lewis acidic sites and promoting electron transfer of Mn2O3 by C-hybridization to improve the peroxymonosulfate activation for Bisphenol A degradation.

The surface acidity and electron transfer performance of manganese oxide catalysts significantly affected its performance of peroxymonosulfate (PMS) activation. In this work, Mn2O3 catalyst was prepared by the precipitation method. The C-hybridization Mn2O3-D (Mn2O3-D) catalyst prepared with disodium oxalate as a precipitant had more Mn3+ and Lewis acid sites on the surface, promoting the binding of PMS on the catalyst surface, which exhibited the best performance in inducing PMS activation to degrade bisphenol A (BPA). Quenching experiments and in situ electron spin resonance (ESR) results indicated that radicals and singlet oxygen were not the main reactive oxygen species (ROSs) in the advanced oxidation process. The chemical probe experiment of phenylmethylsulfone (PMSO) showed that the ≡Mn-OOSO3- metastable intermediate formed by the binding of PMS with Mn sites on the catalyst surface was important active species for contaminants degradation. Contaminants combined with intermediates on the catalyst surface to form the electron transfer channels, which were directly degraded through oxygen-atom-transfer pathway and single-electron-transfer pathway. And the hybridization of C promoted the electron transfer during this process. This work further elucidated the reaction mechanism of PMS activation by manganese oxides, and proposed new ideas for the design of MnOx catalysts for efficient activation of PMS.

Defect Engineered Ru-CoMOF@MoS2 Heterointerface Facilitate Water Oxidation Process.

Catalyst design plays a critical role in ensuring sustainable and effective energy conversion. Electrocatalytic materials need to be able to control active sites and introduce defects in both acidic and alkaline electrolytes. Furthermore, producing efficient catalysts with a distinct surface structure advances our comprehension of the mechanism. Here, a defect-engineered heterointerface of ruthenium doped cobalt metal organic frame (Ru-CoMOF) core confined in MoS2 is reported. A tailored design approach at room temperature was used to induce defects and form an electron transfer interface that enhanced the electrocatalytic performance. The Ru-CoMOF@MoS2 heterointerface obtains a geometrical current density of 10 mA-2 by providing hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at small overpotentials of 240 and 289 mV, respectively. Density functional theory simulation shows that the Co-site maximizes the evolution of hydrogen intermediate energy for adsorption and enhances HER, while the Ru-site, on the other hand, is where OER happens. The heterointerface provides a channel for electron transfer and promotes reactions at the solid-liquid interface. The Ru-CoMOF@MoS2 model exhibits improved OER and HER efficiency, indicating that it could be a valuable material for the production of water-alkaline and acidic catalysts.

Construction of a 0D-2D-2D Sandwich-like Ag/g-C3N4/MoS2 Photocatalyst with Bidirectional Electron Transfer Channels for Photocatalytic Hydrogen Evolution.

Hydrogen (H2) production technology has sparked a boom in research aimed at alleviating environmental pollution and the pressure of nonrenewable energy sources. A key factor in this technology is the use of efficient photocatalysts. In this work, we successfully synthesized a 0D-2D-2D sandwich-like Ag/g-C3N4/MoS2 catalyst with bidirectional electron transfer channels via a calcination-hydrothermal method. The H2 evolution reaction of the Ag/g-C3N4/MoS2 catalyst under simulated solar light irradiation conditions revealed that it achieved a maximum H2 evolution rate of 1061.13 μmol·g-1·h-1, representing a 43.12-fold improvement over pristine g-C3N4. Based on systematic characterization with a combination of theoretical simulations, time-resolved photoluminescence, and electron spin resonance spectra, we demonstrate that the remarkable improvement in photocatalytic performance was ascribed to the bidirectional electron transport channels and 0D-2D-2D structure of the ternary catalyst. This unique structure, which was characterized by a large specific surface area, provided numerous active sites for photocatalytic reactions. Bidirectional electron transfer channels expedited the migration of photogenerated electrons reaching cocatalysts MoS2 and Ag from the conduction band of g-C3N4, consequently enhancing the photocatalytic activity. This study highlights the effectiveness of the bidirectional electron transfer channels in promoting charge carrier migration and suppressing charge carrier recombination for boosting photocatalytic hydrogen evolution and provides an efficient strategy for the actual application of g-C3N4-based photocatalysts.

Ferrocene-Functionalized Atomically Precise Metal Clusters Exhibit Synergistically Enhanced Performance for CO2 Electroreduction.

The integration of organometallic compounds with metal nanoparticles can, in principle, generate hybrid nanocatalysts endowed with augmented functionality, presenting substantial promise for catalytic applications. Herein, we synthesize an atomically precise metal cluster (Ag9Cu6) catalyst integrated with alkynylferrocene molecules (Ag9Cu6-Fc). This hybrid catalyst design facilitates a continuous electron transfer channel via an ethynyl bridge and establishes a distinctive local chemical environment, resulting in remarkably enhanced catalytic activity in CO2 electroreduction. The Ag9Cu6-Fc catalyst achieves a record-high product selectivity of CO Faradaic efficiency of 100 % and an industrial-level CO partial current density of -680 mA/cm2, surpassing the performance of the Ag9Cu6 cluster (62 % and -230 mA/cm2, respectively) without ferrocene functionalization in a membrane electrode assembly cell. Operando experimental and computational findings offer valuable insights into the role of ferrocene functionalization in synergistically improving the catalytic performance of metal clusters, propelling the advancement of metallic-organometallic hybrid nanoparticles for energy conversion technologies.

Photogenerated electron transfer channels in carbon nanotube-intercalated Cu2O nanospheres for boosting visible light-driven CO2 reduction

Photogenerated electron transfer channels in carbon nanotube-intercalated Cu2O nanospheres for boosting visible light-driven CO2 reduction

Construction of multi-pathway electron transfer channel: Mechanism on non-radical to radical promotion in electrocatalysis

Construction of multi-pathway electron transfer channel: Mechanism on non-radical to radical promotion in electrocatalysis

Efficient generation of Fe(IV) = O for water purification in periodate activation process: Reducing Fe orbital occupation and expanding electron transfer channel

The rapid generation of high-valent iron species (Fe(IV) = O) in AOPs has become a challenge for the removal of organic pollutants due to the high electron occupancy in the Fe 3d orbitals and low electron transfer efficiency. Herein, BN modified CuFe2O4 catalysts were constructed by in situ growth of CuFe2O4 nanoparticles on ultrathin BN nanosheets for periodate (PI) catalysis. Especially, the formed Fe-N interface sites not only reduce the electron occupation in the Fe 3d orbitals, but also expand the electronic transfer pathway, thus transforming the oxidation mechanism from one electron process to two electron process for facilitating the Fe(IV) = O and 1O2 generation in the CuFe2O4/BN/PI system. The bimetallic redox cycle between Fe and Cu realizes the accelerated conversion of Fe(III) to Fe(II), promoting the continuous and fast conversion of Fe(II) to Fe(IV) = O via two electron process. As a result, the developed CuFe2O4/BN/PI system exhibits excellent degradation efficiency for oxytetracycline (OTC), achieving 91.02 % OTC removal within 60 min, and maintains relatively high remove efficiency even under different water quality conditions. This research provides a new insight into the evolution of Fe(IV) = O and the deep mechanism of PI activation.

Protective structure coupled dual electron transfer channels for enhancing the activity and stability of photocatalytic CO2 reduction to C2 liquid products

Protective structure coupled dual electron transfer channels for enhancing the activity and stability of photocatalytic CO2 reduction to C2 liquid products

Preparation of Microfiltration Membrane with Good Conductivity and Its Antifouling Performance

Membrane fouling restricts the widespread adoption and application of membrane separation technology. Electrically assisted membrane filtration has proven effective in mitigating this issue. The development of conductive membranes is crucial in this process. In this study, graphene oxide (GO), titanium dioxide (TiO2), and multi-walled carbon nanotubes (MWCNT) were incorporated into polypyrrole/polyvinylidene fluoride (PPy/PVDF) to create the composite conductive membranes GO/PPy/PVDF, TiO2/PPy/PVDF and MWCNT/PPy/PVDF. These membranes demonstrated strong acid resistance, but lacked resistance to strong alkali corrosion. The hydrophilicity of the composite membranes improved compared to that of PPy/PVDF, with the TiO2/PPy/PVDF membrane exhibiting the highest hydrophilicity, evidenced by a contact angle of only 57.52°. The membrane conductivity of MWCNT/PPy/PVDF significantly increased, being 3.27 times that of the PPy/PVDF membrane, due to the inherent excellent conductivity of MWCNT and the increased electron transfer channels. Among the membranes tested, the TiO2/PPy/PVDF membrane, with outstanding hydrophilicity, achieved a water flux of up to 1085L·h−1m−2. It also showed superior antifouling characteristics, with a high flux recovery rate (97.10%) and a low irreversible fouling rate (2.90%) when tested against bovine serum albumin and sodium alginate as foulants.

Two-dimensional QDs-Co-CuS1-x/Ti3C2/TiO2 heterojunction with synergistic unsaturated bimetal sites and sulfur vacancies for highly selective photocatalytic CO2 reduction

The primary factors that determine the efficiency and selectivity of multi-electron photoreduction of CO2 include the chemical properties of the active sites, as well as the kinetics of charge separation and transfer. Herein, a novel two-dimensional QDs-Co-CuS1-x/Ti3C2/TiO2 heterojunction is developed, with Co-CuS1-x quantum dots serving as cocatalysts and Ti3C2 MXene as an effective electron transfer channel. The anchoring effect of Ti3C2 facilitates the formation of robust TiS bonds with Co-CuS1-x, thereby promoting efficient separation and transfer of photoelectrons to the Co-Cu bimetallic active sites. This process enhances the local electron density at these sites and accelerates the kinetics of electron transfer to absorbed CO2. The recyclability of the Co-Cu sites is also significantly enhanced by continuous photoelectron injection. Importantly, DFT calculations indicate that the synergistic dual sites involving highly exposed Co-Cu and S vacancies promote rate-determining step from COO* to COOH*, which may account for the highly selective photoreduction of CO2-to-CO. Benefitting from the synergic effects of the active sites and efficient separation of carriers, the optimized Co-CuS1-x/Ti3C2/TiO2 exhibits a satisfactory CO photoreduction rate of 30.8 µmol∙g−1∙h−1, with an excellent selectivity of 87.9 % and apparent quantum yield of 0.61 % in the absence of any sacrificial reagents, which is 6.5 times higher than Co-CuS1-x, 54.0 times than Ti3C2Tx/TiO2.

Highly enhanced electro-catalytic behavior of an amide functionalized Cu(II) coordination polymer on OER at large current densities

Extensive utilization of fossil fuels has led to their swift exhaustion, causing an escalating energy dilemma and significant environmental apprehensions. This situation has spurred advancement of sustainable energy conversion systems. Electrochemical water splitting is viewed as a capable method for generating hydrogen and oxygen intended for diverse electrochemical energy apparatus. A proficient, multifunctional electro-catalyst capable of facilitating both OERs) and HERs is of paramount importance. In this work, we report Cu-MOF electro-catalyst synthesized via the solvothermal route engaging OER activity using nickel foam (NF) in a 1 M KOH solution. Several analytical techniques were used to investigate the electro-catalysts BET, PXRD, FTIR and oxidation states. The water-splitting evaluation of the LOCOM-1 demonstrated exceptional oxygen activity concerning OER (oxygen evolution reaction), showcasing to extent a current density of 10 mAcm−2 a reduced of 286 mV over potential. Additionally, it exhibited a diminished onset potential of 1.37 V attributable towards a decreased Tafel slope of 44.50 mVdec−1, and a proton couple electron transfer (PCET) channel that is stable over an extended period of time (1000 cycles of cyclic voltammetry and 40 h of chronoamperometry). Therefore, this current endeavour might offer a new prospect or pathway for exploring the OER (Oxygen Evolution Reaction).

Regulating electrons transfer through Pd-O-Bi bridges for boosting photocatalytic CO2 reduction

The photocatalytic efficiency of bismuth-based metal-organic framework (Bi-MOF) is extremely restricted by the rapid recombination of photogenerated electron-hole pairs, which reduce the number of electrons involved in the photocatalytic reduction reaction. Constructing precise interfacial bond bridges between metal nanoparticles (NPs) and MOFs has emerged as an effective strategy to address the above-mentioned issues, promoting the electrons transfer. Herein, this study improves the sluggish dynamics of photogenerated charge in Bi-MOF by inducing the Pd-O-Bi bond bridges at the interface on a Pd NPs-decorated Bi-MOF (Pd/Bi-MOF) nanosheets. This phenomenon results in an interaction between Pd NPs and the Bi-MOF support. And Pd-O-Bi bond bridges provide the fast electron transfer channels, triggering the directional migration of photogenerated electrons from Pd to Bi node, then enhancing the spatial separation of photogenerated electron-hole pairs, finally facilitating overall photocatalytic CO2 reduction. The presence of these bond bridges leads to higher enhancement in CO production for Pd/Bi-MOF nanosheets compared to the Bi-MOF nanosheets under visible light irradiation after 4.5 h. This research demonstrates the importance of interfacial bond bridges and provides a reasonable guide to design efficient photocatalyst for reduction of CO2 to CO.

Microscopic Origin of Twist-Dependent Electron Transfer Rate in Bilayer Graphene.

Using molecular simulation and continuum dielectric theory, we consider how electrochemical kinetics are modulated by the twist angle in bilayer graphene electrodes. By establishing a connection between the twist angle and the screening length of charge carriers within the electrode, we investigate how tunable metallicity modifies the statistics of the electron transfer energy gap. Constant potential molecular simulations show that the activation free energy for electron transfer increases with screening length, leading to a non-monotonic dependence on the twist angle. The twist angle alters the density of states, tuning the number of thermally accessible channels for electron transfer and the reorganization energy by affecting the stability of the vertically excited state through attenuated image charge interactions. Understanding these effects allows us to express the Marcus rate of interfacial electron transfer as a function of the twist angle in a manner consistent with experimental observations.

Dual-site engineering of N vacancies and K single-atoms in C3N4: Enabling spatial charge transfer channels for photocatalysis

Graphitic carbon nitride (C3N4) is a promising photocatalyst due to its suitable band gap and polymer properties, but its efficiency is limited by the poor separation of photoinduced electron/hole (e–/h+) pairs. To address this issue, we propose creating N vacancies within the layers and bridging K single-atoms between the C3N4 layers through the self-assembly of potassium citrate and melamine–urea monomers. The introduction of N vacancies disrupts the symmetry of C3N4, promoting electron transfer along the delocalized π-conjugated network, while the presence of K atoms provides channels for electron transfer between the layers by forming N–K–N bridges, thereby leading to significant enhancement in the separation and transfer of e–/h+ pairs across spatial dimension. As expected, the co-modified C3N4, with N vacancies and K single-atoms (designated as CN-K-VN), exhibits excellent photocatalytic performance, with reaction rate constant of 9.69×10–2 min–1 (7.39×10–2 min–1 in real water environment) for tetracycline, achieving 80% degradation of tetracycline within 20 minutes. The reaction mechanism, as well as the toxicity of the degradation intermediates, is deeply discussed. This study provides a strategy to enhance the spatial separation of electrons for photocatalyst, highlighting its significance role in photocatalysis.