Direct Electron Transport Research Articles

Hierarchical Branched TiO2 Photo/Photoelectrocatalyst with Directed Charge Transfer for Efficient Hydrogen Production from Seawater.

The directed electron transport channel design in semiconductors, which could promote charge utilization, is attractive but rarely reported. Hierarchical branched titanium dioxide (HB-TiO2), possessing a charge cascade transfer channel, was constructed by assembling titanium-defected TiO2 nanobranches on oxygen-defected TiO2 nanobelts. The interfacial Ti/O vacancies have been detected by X-ray photoelectron and electron paramagnetic resonance spectroscopies, and the vacancies act as the "bridge" of photogenerated carrier transport. This structure maintained high photoactivity in H2 production in different mass fractions of NaCl solutions. The photocurrent density of the HB-TiO2 photoanode in natural seawater is 3.9, 2.1, and 2.6 times that of oxygen-defected TiO2 nanobelts, titanium-defected TiO2 nanobranches, and their mixture, respectively. Besides, the charge transport mechanism from the inner lattice to the TiO2 surface is proposed.

Epsilon‐negative materials with lower percolation threshold derived from segregated structures

AbstractEpsilon‐negative materials (ENM) at radio frequency, usually designed based on percolation theory, recently drew much attention because of their potential applications in capacitors, transistors, and antennas. However, randomly distributed conductive functional materials cannot achieve directional long‐range electron transportation within the material, resulting in decreased utilization efficiency. The morphology design of the substrate material can change the distribution state and electron transfer pathway of conductive fillers. By controlling the size of the polystyrene (PS) and the content of multi‐walled carbon nanotubes (MWCNTs), PS/MWCNTs composites with random structures and segregated structures were designed, both of which exhibited negative permittivity with increasing MWCNTs content. Further investigation revealed that negative permittivity behavior is due to the establishment of the conductive network and the plasma oscillation of free electrons. Moreover, components with segregated structures have lower percolation thresholds, as directional electron transport is achieved and conductive fillers are efficiently utilized. This work provides a new method for guiding the electron transport pathway and effectively changing the distribution state of conductive fillers in ENM.Highlights Negative permittivity is achieved by plasma oscillation at radio frequency. The segregated structure leads to a decrease in the percolation threshold. Epsilon‐negative materials have good prospects in inductive components.

(Invited) Designing Photocatalytic Membrane to Direct Electron and Hole Transport

Surface interaction of chromophore or redox active molecule which dictate the efficiency of energy/electron transfer, plays an important role in realizing photocatalytic and optoelectronic applications. Metal halide perovskite nanocrystals are interesting in the sense that they can either transfer energy or selectively transfer electrons or holes to the adsorbed molecules.1,2 The presentation will focus on two specific scenarios of the flow of energy and electron processes in CsPbX3 (X= Br, I) nanocrystal-molecular hybrids. The energy transfer is probed through three moleculr acceptors – rhodamine B (RhB), rhodamine isothiocyanate (RhB-NCS), and rose Bengal (RoseB), which contain an increasing degree of heavy atom pendant groups. Electron and/or hole transfer from excited CsPbX3 nanocrystals to a molecular relay present near the interface offers another avenue to directly convert light energy into chemical energy. Such interfacial electron transfer of semiconductor nanocrystals has been widely explored in photocatalytic processes. A basic understanding of the fundamental differences between the two excited deactivation processes (energy and charge transfer) and ways to modulate them should enable design of more efficient light harvesting assemblies with semiconductor and molecular systems.

Totally Tubular TiO2 Nanotubes as Semiconducting Material for Dye-Sensitized Photoelectrodes

The use of chemical bonds to store solar energy is a promising approach to address the intermittency of the sun by harnessing sunlight to drive chemical transformations. One strategy to drive these processes is to use a bespoke semiconductor surface implemented in a photoelectrode to absorb light and generate charge carriers that can drive redox reactions such as the direct oxidation of adsorbed species on the photoanode. To minimize recombination of photogenerated electron-hole pairs, molecular donor-chromophore-acceptor (D-C-A) systems can be used to sensitize wide bandgap semiconductors for visible light absorption and to generate (high energy) long-living charge separated states. Such assemblies represent a photoelectrode for dye-sensitized photoelectrochemical cells (DS-PECs). Presented here are recent findings using molecularly sensitized TiO2 nanotubes as a nanohybrid architecture for DS-PECs. The highly ordered and oriented 1D-nanostructures are purpose-grown using a self-organizing electrochemical anodization approach. The nanotube mouth is functionalized with a Cu(I)-based donor-chromophore-acceptor system by direct assembly at the surface. The resulting photoanodes are investigated against different water oxidation catalysts (e.g., [Cp*Ir(pyalk)OH], pyalk = 2-(pyridine-2-yl)propan-2-ol; CoOx) for their ability to generate oxidizing equivalents that can subsequently drive follow-on oxidation reactions. A more common TiO2 nanostructure morphology (e.g., nanospheres) and simpler Cu(I)-based chromophores are also examined for comparative purposes to highlight the advantages of the proposed assembly.It is well understood that the role of the semiconductor is to connect the molecular components and transfer/store charge carriers from the excited dye to drive redox processes. The TiO2 nanotubes used here are synthesized by self-organized electrochemical anodization (SOA); a process Involving an anode/cathode arrangement where Ti is used as the anode. This process is a balance between the electrochemical formation of TiO2 and simultaneous chemical dissolution in fluoride-containing electrolytes. The resulting semiconducting film is found to be a vertically oriented, size-controlled, and back-contacted nanostructured array of TiO2 on a foil of titanium. In addition to this composition inheriting high chemical stability, the morphology can grant added benefits such as two-dimensional confinement, directional charge transport and orthogonal charge separation.[1]A crucial limiting factor for the performance of this system is the recombination of the electron-hole pairs. By using a transition metal complex or chromophore (C) that is covalently linked with electron donating (D) and electron accepting (A) moieties, the energy levels can be aligned for charge-transfer processes between the electroactive groups for directional electron transport and formation of a charge-separated state.[2] Copper(I) D-C-A assemblies are also of interest when taking into consideration the low-cost and photophysical properties when compared to typical ruthenium(II) polypyridine chromophores used in these types of cells. Transient photocurrent measurements of the photoelectrode suggest that the TiO2 nanotubes’ mouths generate a base photocurrent, which could be associated with graphitic-like carbon impurities extending light absorption for photoactivity. Furthermore, once the surface is decorated with the copper(I) D-C-A assembly, the photocurrent is significantly increased, enabling light-driven oxidation of CoOx photoelectrochemically deposited on the surface of the photoelectrode.REFERENCES[1] Nguyen, N. T.; Altomare, M.; Yoo, J. E.; Taccardi, N.; Schmuki, P. Noble Metals on Anodic TiO2 Nanotube Mouths: Thermal Dewetting of Minimal Pt Co-Catalyst Loading Leads to Significantly Enhanced Photocatalytic H2 Generation. Adv. Energy Mater. 2016, 6, 1501926. DOI: 10.1002/aenm.201501926[2] Singh, Z.; Kamal, S.; Majewski, M. B. Copper(I) Donor−Chromophore−Acceptor Assembly for Light-Driven Oxidation on a Zinc Oxide Nanowire Electrode. J. Phys. Chem. C. 2022, 126, 39, 16732-16743. DOI: 10.1021/acs.jpcc.2c04652 Figure 1

Directional electron transport and strong chloridion repulsion enabled by Hierarchical NiCo2O4/NiCoP heterojunction for efficient seawater oxidation

Optimizing the efficiencies of both electron transport and chloridion repulsion are highly desired for achieving high-performance oxygen evolution reaction (OER) electrocatalysts in seawater oxidation, but still remains a huge challenge. In this study, an efficient synthetic method is developed to successfully synthesize a novel heterogeneous hollow polyhedron nanocages (denoted as NiCo2O4/NiCoP) with directional electron transport and strong chloridion repulsion properties, which profits from its diverse work functions and anion electrostatic repulsion in heterojunction nanostructure, respectively. Accordingly, NiCo2O4/NiCoP exhibits superior OER activity in 1 M KOH (η = 325 mV@10 mA cm−2) and alkaline simulated seawater (η = 340 mV@10 mA cm−2), as well as outstanding long-term stability. Density functional theory calculations demonstrate that the construction of NiCo2O4/NiCoP heterojunction promotes the directional electron transport in the heterogeneous interface and enables strong chloridion repulsion in comparison with individual NiCo2O4 and NiCoP, thus largely improving its OER performance in alkaline simulated seawater.

Enhanced anaerobic digestion of landfill leachate based on a novel redox mediator: Synergistic mechanism of enhancing extracellular electron transfer

The presence of recalcitrant compounds and toxic substances in landfill leachate results in low anaerobic digestion (AD) efficiency and poor methane production performance. Strengthening the extracellular electron transfer of microorganisms represents an effective approach to promote the AD of landfill leachate. In this study, a novel redox mediator (FeNC-RM) was synthesized through the combination of metal and non-metal doping, intensifying the stable operation of the landfill leachate AD system. Through characterization techniques including X-ray photoelectron spectroscopy and X-ray diffraction, it was observed that FeNC-RM possesses a larger specific surface area, abundant functional groups, and exceptional electrochemical performance. By adding FeNC-RM, the stability and efficiency of the medium-temperature AD system in the treatment of landfill leachate were improved: Obtained a high removal of chemical oxygen demand which was increased by 30 % compared to the control group and enhanced the specific methanogenic activity by 57.5 % compared to the control group. The electron transport system (ETS) activities of the experimental groups with the addition of RMs were all significantly higher than those of the control group, and the ETS activity of the sludge from the FeNC-RM group was 79.6 % higher than that of the control group. Through a comprehensive analysis of the underlying mechanism, it was determined that three aspects synergistically facilitated electron transfer: FeNC-RM, endowed with electrochemical capabilities, assumed a pivotal role in establishing a conduit for electron transport, thus promoting the synthesis of extracellular humic substances and augmenting electron transport activity. Furthermore, the microbial community was optimized by FeNC-RM, thereby fostering a co-nutritional mechanism between hydrolytic acidification bacteria and methanogens, establishing a direct interspecific electron transport pathway. In this study, an “endogenous + exogenous” electron transport model based on the enhanced extracellular electron transport pathway facilitated by FeNC-RM was proposed. This study offered valuable contributions to the advancement of anaerobic treatment technology for landfill leachate.

Synergistic Coupling of Sulfide Electrolyte and Integrated 3D FeS2 Electrode Toward Long‐Cycling All‐Solid‐State Lithium Batteries

FeS2 cathode is promising for all‐solid‐state lithium batteries due to its ultra‐high capacity, low cost, and environmental friendliness. However, the poor performances, induced by limited electrode‐electrolyte interface, severe volume expansion, and polysulfide shuttle, hinder the application of FeS2 in all‐solid‐state lithium batteries. Herein, an integrated 3D FeS2 electrode with full infiltration of Li6PS5Cl sulfide electrolytes is designed to address these challenges. Such a 3D integrated design not only achieves intimate and maximized interfacial contact between electrode and sulfide electrolytes, but also effectively buffers the inner volume change of FeS2 and completely eliminates the polysulfide shuttle through direct solid–solid conversion of Li2S/S. Besides, the vertical 3D arrays guarantee direct electron transport channels and horizontally shortened ion diffusion paths, endowing the integrated electrode with a remarkably reduced interfacial impedance and enhanced reaction kinetics. Benefiting from these synergies, the integrated all‐solid‐state lithium battery exhibits the largest reversible capacity (667 mAh g−1), best rate performance, and highest capacity retention of 82% over 500 cycles at 0.1 C compared to both a liquid battery and non‐integrated all‐solid‐state lithium battery. The cycling performance is among the best reported for FeS2‐based all‐solid‐state lithium batteries. This work presents an innovative synergistic strategy for designing long‐cycling high‐energy all‐solid‐state lithium batteries, which can be readily applied to other battery systems, such as lithium‐sulfur batteries.

Electricity generation by Pseudomonas putida B6-2 in microbial fuel cells using carboxylates and carbohydrate as substrates

Microbial fuel cells (MFCs) employing Pseudomonas putida B6-2 (ATCC BAA-2545) as an exoelectrogen have been developed to harness energy from various conventional substrates, such as acetate, lactate, glucose, and fructose. Owing to its metabolic versatility, P. putida B6-2 demonstrates adaptable growth rates on diverse, cost-effective carbon sources within MFCs, exhibiting distinct energy production characteristics. Notably, the anode chamber's pH rises with carboxylates' (acetate and lactate) consumption and decreases with carbohydrates' (glucose and fructose) utilization. The MFC utilizing fructose as a substrate achieved the highest power density at 411 mW m−2. Initial analysis revealed that P. putida B6-2 forms biofilms covered with nanowires, contributing to bioelectricity generation. These microbial nanowires are likely key players in direct extracellular electron transport through physical contact. This study established a robust foundation for producing valuable compounds and bioenergy from common substrates in bioelectrochemical systems (BESs) utilizing P. putida as an exoelectrogen.

Silver Nanowires Cascaded Layered Double Hydroxides Nanocages with Enhanced Directional Electron Transport for Efficient Electrocatalytic Oxygen Evolution.

Designing and fabricating highly efficient oxygen evolution reaction (OER) electrocatalytic materials for water splitting is a promising and practical approach to green and sustainable low-carbon energy systems. Herein, a facile in situ growth self-template strategy by using ZIF-67 as a consumable layered double hydroxides (LDHs) template and silver nanowires (AgNWs) as 1D conductive cascaded substrate to controllably synthesize the target AgNWs@CoFe-LDH composites with unique hollow shell sugar gourd-like structure and enhanced directional electron transport effect is reported. The AgNWs exhibit the key functions of the close connection of CoFe-LDH nanocages and the support of the directional electron transport effect in the composite catalyst inducing electrons directionally moving from CoFe-LDH to AgNWs. Meanwhile, the CoFe-LDH nanocages with ultrathin nanosheets and hollow structural properties show abundant active sites for electrocatalytic oxygen generation. The versatile AgNWs@CoFe-LDH catalyst with optimized components, enhanced directional electron transport, and synergistic effect achieves high OER performance with the overpotential of 207 mV and long-term 50 h stability at 10 mA cm-2 in an alkaline medium. Moreover, in-depth insights into the microstructure, structure-activity relationships, identification of key intermediate species, and a proton-coupled four-electron OER mechanism based on experimental discovery and theoretical calculation are also demonstrated.

Highly conductive riboflavin-based carbon quantum dot–embedded SiO2@MoS2 nanocomposite for enhancing bioelectricity generation through synergistic direct and indirect electron transport

A microbial fuel cell (MFC) is an advanced green battery that has limited application because of its low current density. In the present study, Shewanella oneidensis MR-1, which is an electricity-producing bacterium, was used in an electrochemical reactor as a bacterial model. Mesoporous spherical silica nanoparticles (NPs) loaded with riboflavin (RF) were prepared as the starting material, following which surface modification was conducted to expose the thiol group, which considerably increased the affinity of the NPs to MoS2 and resulted in the formation of a dense MoS2 shell on the surface after calcination. Moreover, the loaded RFs were successfully transformed into RF-based carbon quantum dots (CQDs), which resulted in a substantial increase in conductivity. The CQD-embedded SiO2@MoS2 NPs, which contained redox-active N-doped CQDs and had a metallic MoS2 shell, were able to receive electrons from exoelectrogenic bacteria (charging) and transfer electrons to an indium tin oxide electrode (discharging). Thus, these NPs could act as an electron nanoshuttle and a conductive medium in biofilms for enhancing systematic extracellular electron transport. A 10-fold increase in bioelectricity production than no NPs addition was achieved, which confirmed the applicability of the aforementioned NPs in advanced MFC applications. The NPs prepared in this study, which mimic biological electron shuttles (e.g., RF) in long-distance conduction, can usher in a new era in the development of advanced MFCs.

Indirect and direct electronic transitions and electron transport properties of van der Waals NbOCl2.

In this paper, the optical and electron transport properties of the two-dimensional (2D) van der Waals (vdW) niobium oxide dichloride (NbOCl2) crystal with extremely high second-order nonlinear coefficients are investigated theoretically. We found that the strong absorption of NbOCl2 in the infrared region is caused by the indirect transition accompanied by phonons and confirmed that the interaction between layers is very weak. However, the study of electron transport properties shows that the interlayer interaction of NbOCl2 has a certain degree of influence on the scalability of electrical and optical properties. Because of the strong anisotropy of the NbOCl2 material, it will be a more optimized choice for constructing on-chip photoelectric or thermal devices in the Nb-Cl-Nb direction.

Assessing the mitochondrial safety profile of the molnupiravir active metabolite, β-d-N4-hydroxycytidine (NHC), in the physiologically relevant HepaRG model.

β-d-N4-Hydroxycytidine (NHC) is the active metabolite of molnupiravir, a broad-spectrum antiviral approved by the MHRA for COVID-19 treatment. NHC induces lethal mutagenesis of the SARS-CoV-2 virus, undergoing incorporation into the viral genome and arresting viral replication. It has previously been reported that several nucleoside analogues elicit off-target inhibition of mitochondrial DNA (mtDNA) or RNA replication. Although NHC does not exert these effects in HepG2 cells, HepaRG are proven to be advantageous over HepG2 for modelling nucleoside analogue-induced mitochondrial dysfunction. Therefore, the objective of this work was to assess the mitotoxic potential of NHC in HepaRG cells, a model more closely resembling physiological human liver. Differentiated HepaRG cells were exposed to 1-60 μM NHC for 3-14 days to investigate effects of sub-, supra-, and clinically-relevant exposures (in the UK, molnupiravir for COVID-19 is indicated for 5 days and reported Cmax is 16 μM). Following drug incubation, cell viability, mtDNA copy number, mitochondrial protein expression, and mitochondrial respiration were assessed. NHC induced minor decreases in cell viability at clinically relevant exposures, but did not decrease mitochondrial protein expression. The effects on mtDNA were variable, but typically copy number was increased. At supra-clinical concentrations (60 μM), NHC reduced mitochondrial respiration, but did not appear to induce direct electron transport chain dysfunction. Overall, NHC does not cause direct mitochondrial toxicity in HepaRG cells at clinically relevant concentrations, but may induce minor cellular perturbations. As HepaRG cells have increased physiological relevance, these findings provide additional assurance of the mitochondrial safety profile of NHC.

Tools to Simulate Resonance Raman Spectra for in-Situ Studies of Electron Transport Mediators and Bioelectrocatalysts

Raman spectroscopy is widely applied as an in-situ probe of electrochemical processes. When the excitation light is resonant with an electronic transition, the detected signal can be enhanced by more than 1,000-fold. Resonance Raman (RR) spectroscopy has broad application in the study of common organic electron transport mediators (i.e., viologens, phenazines, photosynthetic pigments) and active sites of redox proteins (i.e., laccases, peroxidases, flavin-containing enzymes). To support investigations of bioelectrocatalytic membranes, we have been adapting RR spectroscopy to gain insights into the properties of immobilized redox mediators and biocatalyst active sites.1,2 Computational methods can be useful for guiding spectral interpretation. This poster reports on applications of recently advanced time-dependent density functional theory (TDDFT) codes that enable the simulation of RR spectra for small electron transport mediators (e.g., methyl viologen radical anion) and redox protein active site models (e.g., laccase T1 site mimics). The ORCA program suite3 was adapted. A series of Cu-centered compounds that model the T1 active site in laccases was studied along with the methyl viologen radical cation. The T1 site in laccases facilitates direct electron transport to an electrode and is a target for in-situ RR measurements. The reported work demonstrates careful selection of the functional (B3-LYP versus the long-range corrected hybrid exchange functional, ωB97X-D3) results in TDDFT-calculated electronic absorption and RR spectra that have features in excellent agreement with experiment. The results provide a foundation to build from in advancing models of small redox mediators and laccase catalytic active sites in support of sustainable technologies. Ozuguzel, U.; Aquino, A.J.A.; Nieman, R.; Minteer, S.D.; Korzeniewski, C. “Calculation of Resonance Raman Spectra and Excited State Properties for Blue Copper Protein Model Complexes” ACS Sustainable Chem. Eng. 2022, 10, 14614. Xu, J.; Koh, M.; Minteer, S. D.; Korzeniewski, C. “In Situ Confocal Raman Microscopy of Redox Polymer Films on Bulk Electrode Supports” ACS Measurement Science Au 2023 (DOI: 10.1021/acsmeasuresciau.2c00064). Neese, F.; Wennmohs, F.; Becker, U.; Riplinger, C. “ORCA Quantum Chemistry Program Package” J. Chem. Phys. 2020, 152, 224108.

Electrochemical Nonenzymatic Acetone Sensing: A Novel Approach of Biosensor Platform Based on CNT/CuO Nanosystems

AbstractA promising approach for noninvasive medical diagnosis may be to measure the VOCs produced by metabolic changes or pathological disorders in human sweat, such as measuring the acetone levels in the presence of diabetes. Acetone is a by‐product of fat catabolism and serves as an indicator of ketosis and diabetes. The measurement of acetone may be used instead of glucose monitoring. Current research aims to develop and improve noninvasive methods of detecting acetone in sweat that are accurate, sensitive, and stable. The carbon nanotubes (CNTs)–copper oxide (CuO) nanocomposite (NC) improves direct electron transport to the electrode surface in this study. The complex‐precipitation method is used to make this NC. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) are used to investigate the crystal structure and morphology of the prepared catalyst. Using cyclic voltammetry (CV) and amperometry, the electrocatalytic activity of the as‐prepared catalyst is evaluated. The electrocatalytic activity in artificial sweat solution is examined at various scan rates and acetone concentrations. The detection limit of the CNTs‐CuO NC catalyst is 0.05 mm, with a sensitivity of 16.1 mA cm−2 µm−1 in a linear range of 1–50 mm. Furthermore, this NC demonstrates a high degree of selectivity for various biocompounds found in sweat, with no interfering cross‐reactions from these species. The CNT‐CuO NC, as produced, has good sensitivity, rapid reaction time (2 s), and stability, indicating its potential for acetone sensing.

Dye-sensitized solar cells containing photoelectrodes with TiO2 grids

A 90-nm-thick TiO2 grid is created through photolithography, sputtering and lift-off process in this study. A nanoporous film is deposited on the TiO2 grid. The grid induces a protrusive structure in the nanoporous film. Experimental results demonstrate that introducing the TiO2 grid into a dye-sensitized solar cell increases its power conversion efficiency by 25% compared to a dye-sensitized solar cell lacking a TiO2 grid. Consequently, the TiO2 grid proves beneficial in augmenting the power conversion efficiency of the dye-sensitized solar cell. The increased power conversion efficiency of the dye-sensitized solar cell containing the TiO2 grid is attributed to the large surface area and directional electron transport channels of the protrusive structure. The TiO2 grid offers advantages such as simple fabrication, cost-effective production and improved power conversion efficiency.

Surface reconstruction and directed electron transport in NiSe2/MoSe2 Mott-Schottky heterojunction catalysts promote urea-assisted water splitting

The construction of cost-effective electrocatalysts with remarkable activity and durability for the urea oxidation reaction (UOR) is urgently needed to achieve sustainable hydrogen production. Herein, a three-dimensional (3D) nanostructure with uniform NiSe2/MoSe2 Mott-Schottky heterojunction nanoneedle arrays densely grown on carbon cloth was designed and fabricated by a hydrothermal method followed by selenization treatment. In the UOR process, NiSe2/MoSe2 undergoes surface reconstruction into a Mo-NiOOH/NiSe2 composite structure, and Mo-doping can optimize the adsorption/desorption of UOR intermediates. In the hydrogen evolution reaction (HER) process, the directed electron transfer brought by the Mott-Schottky heterojunction can modulate the electronic structure and optimize the d-band center, thus promoting HER. The well-designed NiSe2/MoSe2 as a bifunctional catalyst for urea-assisted electrolysis can reach 10 mA cm−2 at only 1.44 V with almost no performance degradation for 48 h. This work provides a promising avenue to develop efficient HER/UOR bifunctional catalysts toward urea-assisted water electrolysis.

Enhanced piezocatalytic hydrogen evolution performance of bismuth vanadate by the synergistic effect of facet engineering and cocatalyst engineering

Developing piezocatalysts with excellent piezocatalytic hydrogen evolution reaction (HER) performance is highly desired but also challenging. Here, facet engineering and cocatalyst engineering are employed to synergistically improve the piezocatalytic HER efficiency of BiVO4 (BVO). Monoclinic BVO catalysts with distinct exposed facets are synthesized by adjusting pH of hydrothermal reaction. The BVO with highly exposed {110} facet exhibits a superior piezocatalytic HER performance (617.9 μmol g-1h−1) compared with that with {010} facet, owing to the strong piezoelectric property, high charge transfer efficiency, and excellent hydrogen adsorption/desorption capacity. The HER efficiency is enhanced by 44.7% by selectively depositing cocatalyst of Ag nanoparticles specifically on the reductive {010} facet of BVO, where the Ag-BVO interface provides the directional electron transport for high-efficiency charge separation. Under the collaboration between cocatalyst of CoOx on {110} facet and the hole sacrificial agent of methanol, the piezocatalytic HER efficiency is evidently enhanced by 2 times because CoOx and methanol can impede the water oxidation and improve the charge separation. This easy and simple strategy provides an alternative perspective on designing high-performance piezocatalysts.

Membrane engineering of Escherichia coli based on “Building bridges” and “Digging tunnels” to improve electro-fermentation of succinate

Succinate is the end product of anaerobic metabolism of Escherichia coli, and its over-production needs abundant reducing force. Electro-fermentation (EF) is a novel biotechnology to steer and control fermentative processes by supplying extra electrons. However, E.coli is a non-electroactive strain which needs the support of electron shuttle in EF. Here, membrane engineering strategies of “Building bridges” via screening direct electron transport pathway and “Digging tunnels” via screening membrane porins were developed to improve the transmembrane transport of electron during the cathodic electro-fermentation (CEF). As a result, the total electron quantity during electro-fermentation was increased from 1.21 mmol to 7.90 mmol, and succinate yield was increased by 23.3% when these strategies simultaneously were applied to the succinate candidate E. coli Suc260. Hence, this study provides a reference mode for designing and constructing non-electroactive bacteria for electro-fermentation of reductive metabolites.

TiO2-rGO-Cu complex: A photocatalyst possessing an interfacial electron transport mechanism to enhance hydrogen production from seawater

Photocatalytic hydrogen production from seawater has great prospects for generating clean energy from renewable resources. We designed a TiO2-rGO-Cu photocatalyst that possesses a pathway for directed electron transfer from nitrogen-doped TiO2 to rGO and then to Cu nanoparticles, which leads to efficient electron-hole pairs separation. Results show that TiO2-rGO-Cu has a hydrogen production rate of 16.08 mmol h−1g−1 in simulated seawater, which is as much as 25 times higher than that of TiO2. The mechanism for a highly efficient directional interfacial electron transport is proposed. The strategy could be effective for designing new photocatalysts for hydrogen production from seawater.

Facile three-step strategy to design CdS@Bi2Se3 core-shell nanostructure: An efficient electrode for supercapacitor application

In this study, we utilized a successive ionic layer adsorption and reaction (SILAR) route to attach bismuth selenide (Bi2Se3) nanoparticles on one dimensional (1D) cadmium sulfide nanowires (CdS NWs) at ambient temperature (27 °C) to design CdS@Bi2Se3 core-shell nanostructure towards active electrode for supercapacitor application. To verify and explore the retrieved surface configuration, structural, elemental, compositional, and surface morphological investigations were performed. The designed CdS@Bi2Se3 core-shell nanostructure not only offers the tremendous number of active areas, but also a continuous and quick one directional electron transport channels, demonstrating noticeable electrochemical performance with specific capacitance of 198 F g−1 (aerial capacitance 59.5 mF/cm2) with 80% cyclic retention @ 2000 cycles. Superior electrochemical activity was enhanced through the mutualistic involvement of Na+ ion insertion/extraction via non-stoichiometric bismuth selenide, which was well supported through electrochemical impedance (EIS) studies.