Modulating Electronic Structure by Etching Strategy to Construct NiSe2 /Ni0.85 Se Heterostructure for Urea-Assisted Hydrogen Evolution Reaction.

Exploring and developing novel strategies for constructing heterostructure electrocatalysts is still challenging for water electrolysis. Herein, a creative etching treatment strategy is adopted to construct NiSe2 /Ni0.85 Se heterostructure. The rich heterointerfaces between NiSe2 and Ni0.85 Se emerge strong electronic interaction, which easily induces the electron transfer from NiSe2 to Ni0.85 Se, and tunes the charge-state of NiSe2 and Ni0.85 Se. In the NiSe2 /Ni0.85 Se heterojunction nanomaterial, the higher charge-state Ni0.85 Se is capable of affording partial electrons to combine with hydrogen protons, inducing the rapid formation of H2 molecule. Accordingly, the lower charge-state NiSe2 in the NiSe2 /Ni0.85 Se heterojunction nanomaterial is more easily oxidized into high valence state Ni3+ during the oxygen evolution reaction (OER) process, which is beneficial to accelerate the mass/charge transfer and enhance the electrocatalytic activities towards OER. Theoretical calculations indicate that the heterointerfaces are conducive to modulating the electronic structure and optimizing the adsorption energy toward intermediate H* during the hydrogen evolution reaction (HER) process, leading to superior electrocatalytic activities. To expand the application of the NiSe2 /Ni0.85 Se-2h electrocatalyst, urea is served as the adjuvant to proceed with the energy-saving hydrogen production and pollutant degradation, and it is proven to be a brilliant strategy.

Dual Atoms (Fe, F) Co-Doping Inducing Electronic Structure Modulation of NiO Hollow Flower-Spheres for Enhanced Oxygen Evolution/Sulfion Oxidation Reaction Performance.

Heteroatoms Fe, F co-doped NiO hollow spheres (Fe, F-NiO) are designed, which simultaneously integrate promoted thermodynamics by electronic structure modulation with boosted reaction kinetics by nano-architectonics. Benefiting from the electronic structure co-regulation of Ni sites by introducing Fe and F atoms in NiO , as the rate-determined step (RDS), the Gibbs free energy of OH* intermediates (ΔGOH* ) for Fe, F-NiO catalyst is significantly decreased to 1.87 eV for oxygen evolution reaction (OER) compared with pristine NiO (2.23 eV), which reduces the energy barrier and improves the reaction activity. Besides, densities of states (DOS) result verifies the bandgap of Fe, F-NiO(100) is significantly decreased compared with pristine NiO(100), which is beneficial to promote electrons transfer efficiency in electrochemical system. Profiting by the synergistic effect, the Fe, F-NiO hollow spheres only require the overpotential of 215 mV for OER at 10 mA cm-2 and extraordinary durability under alkaline condition. The assembled Fe, F-NiO||Fe-Ni2 P system only needs 1.51 V to reach 10 mA cm-2 , also exhibits outstanding electrocatalytic durability for continuous operation. More importantly, replacing the sluggish OER by advanced sulfion oxidation reaction (SOR) not only can realize the energy saving H2 production and toxic substances degradation, but also bring additional economic benefits.

Interfacial Charge Transfer in MoS2/TiO2 Heterostructured Photocatalysts: The Impact of Crystal Facets and Defects.

One of the most challenging issues in photocatalytic hydrogen evolution is to efficiently separate photocharge carriers. Although MoS2 loading could effectively improve the photoactivity of TiO2, a fundamental understanding of the charge transfer process between TiO2 and MoS2 is still lacking. Herein, TiO2 photocatalysts with different exposed facets were used to construct MoS2/TiO2 heterostructures. XPS, ESR, together with PL measurements evidenced the Type II electron transfer from MoS2 to {001}-TiO2. Differently, electron-rich characteristic of {101}-faceted TiO2 were beneficial for the direct Z-scheme recombination of electrons in TiO2 with holes in MoS2. This synergetic effect between facet engineering and oxygen vacancies resulted in more than one order of magnitude enhanced hydrogen evolution rate. This finding revealed the elevating mechanism of constructing high-performance MoS2/TiO2 heterojunction based on facet and defect engineering.

The electrochemical properties of Co3O4 as a lithium-ion battery electrode: a first-principles study.

Extensive first principles calculations were performed to study the structural and electrochemical features of Co3O4 during its lithiation process as an anode material for lithium-ion batteries (LIBs). We found that with up to 8 mol Li in Co3O4, the formed LinCo3O4 structures are stable for low Li concentrations of n ≤ 1, but obvious structure distortions and volume expansions occur for LinCo3O4 with n > 1. This may be the reason why Co3O4 has a high Li capability but low cycling life as a LIB anode. The ab initio molecular dynamics simulations for LinCo3O4 (n = 2, 4, 8) further suggest a two-step electrochemistry process of Co3O4 → CoO → Co upon the lithiation process. We detected a distorted surface structure as Li atoms react with the Co3O4(110) surface, which also reduces the rate capability of the Co3O4 anode.

Nanopolygons of Monolayer MS2: Best Morphology and Size for HER Catalysis.

With first-principles calculations, we find a new strategy for developing high-performance catalysts for hydrogen evolution reaction (HER) via controlling the morphology and size of nanopolygons of monolayer transition-metal dichalcogenides (npm-MS2, with M = Mo, W, or V). Particularly, through devising a quantitative method to measure HER-active sites per unit mass and using such HER site density to comparatively gauge npm-MS2 performance, we identify three keys in making npm-MS2 with optimal HER performance: (a) npm-MS2 should be triangular with each edge being M-terminated and each edge-M atom passivated by one S atom; (b) each edge of npm-MoS2 and WS2 should have 5-6 metal atoms as HER site density drops below/above these sizes optimal both for HER and practical npm growth; and (c) npm-VS2 is immune to this overly fastidious size dependence. Known experimental data on npm-MoS2 indeed support the plausibility of practicing these design rules. We expect that raising the nucleation density and controlling the growth time to favor the production of our proposed ultrasmall npm-MS2 are critical but practical. Research on npm-VS2 would bear the highest impact because of its size-forgiving HER performance and relatively high abundance and low cost.

Highly Stretchable Superhydrophobic Composite Coating Based on Self-Adaptive Deformation of Hierarchical Structures.

With the rapid development of stretchable electronics, functional textiles, and flexible sensors, water-proof protection materials are required to be built on various highly flexible substrates. However, maintaining the antiwetting of superhydrophobic surface under stretching is still a big challenge since the hierarchical structures at hybridized micro-nanoscales are easily damaged following large deformation of the substrates. This study reports a highly stretchable and mechanically stable superhydrophobic surface prepared by a facile spray coating of carbon black/polybutadiene elastomeric composite on a rubber substrate followed by thermal curing. The resulting composite coating can maintain its superhydrophobic property (water contact angle ≈170° and sliding angle <4°) at an extremely large stretching strain of up to 1000% and can withstand 1000 stretching-releasing cycles without losing its superhydrophobic property. Furthermore, the experimental observation and modeling analysis reveal that the stable superhydrophobic properties of the composite coating are attributed to the unique self-adaptive deformation ability of 3D hierarchical roughness of the composite coating, which delays the Cassie-Wenzel transition of surface wetting. In addition, it is first observed that the damaged coating can automatically recover its superhydrophobicity via a simple stretching treatment without incorporating additional hydrophobic materials.

Depth profiling cross-linked poly(methyl methacrylate) films: a time-of-flight secondary ion mass spectrometry approach.

RATIONALE: In order to determine the degree of cross-linking on the surface and its variations in a nanometer-scale depth of organic materials, we developed an approach based on time-of-flight secondary ion mass spectrometry (TOF-SIMS), which provides rich chemical information in the form of fragment ions. TOF-SIMS is extremely surface-sensitive and capable of depth profiling with the use of a sputter ion beam to remove controllable amounts of substance. METHODS: Poly(methyl methacrylate) (PMMA) films spin-coated on a Si substrate were cross-linked using a recently developed, surface sensitive, hyperthermal hydrogen projectile bombardment technique. The ion intensity ratio between two ubiquitous hydrocarbon ions, C6 H- and C4 H- , detected in TOF-SIMS, denoted as ρ, was used to assess the degree of cross-linking of the PMMA films. The cross-linking depth of the PMMA films was revealed by depth profiling ρ into the polymer films using a C60+ sputter beam. RESULTS: The control PMMA film spin-coated on a Si substrate was characterized by ρ = 32% on its surface when using a 25 keV Bi3+ primary ion beam. This parameter on the PMMA films subjected to HHIC treatment for 10, 100 and 500 s increased to 45%, 56% and 65%, respectively. The depth profiles of ρ obtained using a 10 keV C60+ ion beam resembled an exponential decay, from which the cross-linking depth was estimated to be 3, 15 and 39 nm, respectively, for the three cross-linked PMMA films. CONCLUSIONS: We demonstrated that the ion intensity ratio of C6 H- to C4 H- detected in TOF-SIMS provides a unique and simple means to assess the degree of cross-linking of the surface of PMMA films cross-linked by the surface sensitive hyperthermal hydrogen projectile bombardment technique. With a C60+ sputter beam, we were able to depth profile the PMMA films and determine cross-linking depths of the cross-linked polymer films at nanometer resolutions. Copyright © 2017 John Wiley & Sons, Ltd.

Edges of graphene and carbon nanotubes with high catalytic performance for the oxygen reduction reaction.

We invented a practical and simple wet-grinding method to break conventional graphene sheets and CNTs for the production of new graphene/CNTs with adequate edge density (about 25 000 atoms per graphene-fragment of about 1 µm2 in size) and no detectable changes in intrinsic defects, extrinsic impurities, and even surface-area. Measurements using the standard cyclic voltammetry, rotating disk electrode and rotating ring-disk electrode techniques all confirm that such mildly fragmented graphene, as well as carbon-nanotubes treated similarly using this wet-grinding method, can facilitate the fast 4-electron oxygen reduction reaction (ORR) pathway. Our first-principles computational studies of the ORR on graphene, as well as the relevant known data in the literature, support an intriguing proposition that the ORR can be speeded up simply by increasing the edge-density of graphene. The adsorption of O2 involving both oxygen atoms, which causes O-O elongation, is best facilitated at the edge of graphene, facilitating a multi-step 4-electron ORR process.

Influence of magnetic ordering and Jahn-Teller distortion on the lithiation process of LiMn2O4.

We performed extensive first-principles studies on the magnetic ordering and Jahn-Teller (JT) distortion of spinel LiMn2O4, a promising candidate for cathode materials in Li-ion batteries. We find that the ground state of LiMn2O4 is an anti-ferromagnetic (AFM) orthorhombic spinel structure, where AFM Mn3+ layers and FM Mn4+ layers alternate along the [001] direction and the 90° Mn3+-O2--Mn3+ in the Mn3+-(001) planes are AFM coupling, forming an indirect Kramers-Anderson superexchange. The coplanar Mn3+ ions maximize the JT distortion and the AFM magnetic orderings further strengthen the interaction between Mn3+ cations and O2- anions, making the structure stable. Li diffusion in such a stable LiMn2O4 material will occur through a ring consisting of six Mn atoms, and the energy barrier of Li diffusion is dependent on the valence states of those Mn atoms. Our theoretical results give insights into exploring the ground state of related JT magnetic materials, and also provide information on the performance improvement of LiMn2O4 cathode materials.

Tuning band gaps and optical absorption of BiOCl through doping and strain: insight form DFT calculations.

Bismuth oxyhalides (BiOX, X = Cl, Br, and I) are a new family of promising photocatalysts. BiOCl and BiOBr possess large band gaps and weak absorption in visible light regions, which limit their applications. Although the band gap of BiOI is suitable to absorb most of the visible light, its redox capability is very weak. In this work, the doping and strain effects on the electronic structures and optical properties of BiOCl are explored using first principle calculations. The results show that doping in BiOCl, especially co-doping of Sb and I atoms, can obviously decrease the band gaps along with enhancing the optical absorption coefficients of pristine BiOCl because of the electronegativity difference between Sb/I atoms and Bi/Cl atoms. Meanwhile the band gap of BiOCl can be tuned under strain. This work offers potential strategies to enhance BiOCl absorption coefficients in the visible light region and its photocatalyst activity.

Al atom on MoO3(010) surface: adsorption and penetration using density functional theory.

Interfacial issues, such as the interfacial structure and the interdiffusion of atoms at the interface, are fundamental to the understanding of the ignition and reaction mechanisms of nanothermites. This study employs first-principle density functional theory to model Al/MoO3 by placing an Al adatom onto a unit cell of a MoO3(010) slab, and to probe the initiation of interfacial interactions of Al/MoO3 nanothermite by tracking the adsorption and subsurface-penetration of the Al adatom. The calculations show that the Al adatom can spontaneously go through the topmost atomic plane (TAP) of MoO3(010) and reach the 4-fold hollow adsorption-site located below the TAP, with this subsurface adsorption configuration being the most preferred one among all plausible adsorption configurations. Two other plausible configurations place the Al adatom at two bridge sites located above the TAP of MoO3(010) but the Al adatom can easily penetrate below this TAP to a relatively more stable adsorption configuration, with a small energy barrier of merely 0.2 eV. The evidence of subsurface penetration of Al implies that Al/MoO3 likely has an interface with intermixing of Al, Mo and O atoms. These results provide new insights on the interfacial interactions of Al/MoO3 and the ignition/combustion mechanisms of Al/MoO3 nanothermites.

Bipolar doping of double-layer graphene vertical heterostructures with hydrogenated boron nitride.

Using first-principles calculations, we examined the bipolar doping of double-layer graphene vertical heterostructures, which are constructed by hydrogenated boron nitride (BN) sheets sandwiched into two parallel graphene monolayers. The built-in potential difference in hydrogenated BN breaks the interlayer symmetry, resulting in the p- and n-type doping of two graphene layers at 0.83 and -0.8 eV, respectively. By tuning the interlayer spacing between the graphene and hydrogenated BN, the interfacial dipole and screening charge distribution can be significantly affected, which produces large modulations in band alignments, doping levels and tunnel barriers. Furthermore, we present an analytical model to predicate the doping level as a function of the average interlayer spacing. With large interlayer spacings, the "pillow effect" (Pauli repulsion at the highly charge overlapped interface) is diminished and the calculated Dirac point shifts are in good accordance with our prediction models. Our investigations suggest that this double-layer graphene heterostructures constructed using two-dimensional Janus anisotropic materials offer exciting opportunities for developing novel nanoscale optoelectronic and electronic devices.

Band gap engineering of FeS2 under biaxial strain: a first principles study.

The promising photovoltaic activity of pyrite (FeS2) is attributed to its excellent optical absorptivity and earth abundance, but its band gap, 0.95 eV, is slightly lower than the optimum value of 1.3 eV. Here we report the first investigation of strained FeS2, whose band gap can be increased by ∼0.3 eV. The influence of uniaxial and biaxial strains on the atomic structure as well as the electronic and optical properties of bulk FeS2 is systematically examined by the first principles calculations. We found that the biaxial strain can effectively increase the band gap with respect to uniaxial strain. Our results indicate that the band gap increases with increasing tensile strain to its maximum value at 6% strain, but under the increasing compressive strain, the band gap decreases almost linearly. Moreover, the low intensity states at the bottom of the conduction band disappear and a sharp increase in the intensity appears at the lower energy level under the tensile strain, which causes the red shift of the absorption edge and enhances the overall optical absorption. With the increase of the band gap and enhanced optical absorption, FeS2 will make a better photovoltaic material.

Self-assembled monolayers of CH3S from the adsorption of CH3SSCH3 on Au(111).

By performing density functional theory calculations, we have examined the adsorption of dimethyl disulfide (CH3SSCH3) on Au(111). In addition, we have also charted the reaction paths leading to dissociation of the S-S bond and the formation of thiolate-adatom species. Further, we have simulated the scanning tunneling microscopic (STM) images of the key adsorption intermediates and products and compared them with the experimental data available in the literature. In summary, our computations show that CH3SSCH3 adsorbs on Au(111) non-dissociatively with a moderate adsorption energy 0.42 eV for the trans-conformation which is 0.24 eV more stable than its cis-isomer. When the adsorbed trans-CH3SSCH3 dissociates at low temperature, the two CH3S fragments are retained by the closest neighboring sites and the trans-conformation of them prior to S-S dissociation can be preserved. The activation barrier to rotating the CH3S fragments on Au(111) is 0.17 eV so a moderate temperature rise can facilitate the transformation of the trans-conformation and generate a mixture of the trans- and cis-conformation. Our calculations also show that intrinsic defects such as gold adatoms (Auad) are active in CH3SSCH3 dissociation in two mechanisms: a direct mechanism in which CH3SSCH3 dissociation drives Auad formation and CH3S-Auad formation simultaneously, with leftover vacancies as by-products; a sequential mechanism in which Auad is present in advance and subsequently interacts with a nearby CH3S fragment to form CH3S-Auad. The respective activation barriers are 0.15 and 0.32 eV for the trans- and cis-CH3S-Auad-SCH3 complex along the direct mechanism, and 0.21 and 0.18 eV along the sequential mechanism.

Diverse and tunable electronic structures of single-layer metal phosphorus trichalcogenides for photocatalytic water splitting.

The family of bulk metal phosphorus trichalcogenides (APX3, A = M(II), M(I)(0.5)M(III)(0.5); X = S, Se; M(I), M(II), and M(III) represent Group-I, Group-II, and Group-III metals, respectively) has attracted great attentions because such materials not only own magnetic and ferroelectric properties, but also exhibit excellent properties in hydrogen storage and lithium battery because of the layered structures. Many layered materials have been exfoliated into two-dimensional (2D) materials, and they show distinct electronic properties compared with their bulks. Here we present a systematical study of single-layer metal phosphorus trichalcogenides by density functional theory calculations. The results show that the single layer metal phosphorus trichalcogenides have very low formation energies, which indicates that the exfoliation of single layer APX3 should not be difficult. The family of single layer metal phosphorus trichalcogenides exhibits a large range of band gaps from 1.77 to 3.94 eV, and the electronic structures are greatly affected by the metal or the chalcogenide atoms. The calculated band edges of metal phosphorus trichalcogenides further reveal that single-layer ZnPSe3, CdPSe3, Ag0.5Sc0.5PSe3, and Ag0.5In0.5PX3 (X = S and Se) have both suitable band gaps for visible-light driving and sufficient over-potentials for water splitting. More fascinatingly, single-layer Ag0.5Sc0.5PSe3 is a direct band gap semiconductor, and the calculated optical absorption further convinces that such materials own outstanding properties for light absorption. Such results demonstrate that the single layer metal phosphorus trichalcogenides own high stability, versatile electronic properties, and high optical absorption, thus such materials have great chances to be high efficient photocatalysts for water-splitting.

Shewanella oneidensis MR-1 bacterial nanowires exhibit p-type, tunable electronic behavior.

The study of electrical transport in biomolecular materials is critical to our fundamental understanding of physiology and to the development of practical bioelectronics applications. In this study, we investigated the electronic transport characteristics of Shewanella oneidensis MR-1 nanowires by conducting-probe atomic force microscopy (CP-AFM) and by constructing field-effect transistors (FETs) based on individual S. oneidensis nanowires. Here we show that S. oneidensis nanowires exhibit p-type, tunable electronic behavior with a field-effect mobility on the order of 10(-1) cm(2)/(V s), comparable to devices based on synthetic organic semiconductors. This study opens up opportunities to use such bacterial nanowires as a new semiconducting biomaterial for making bioelectronics and to enhance the power output of microbial fuel cells through engineering the interfaces between metallic electrodes and bacterial nanowires.

Optimization of mid-infrared noninvasive blood-glucose prediction model by support vector regression coupled with different spectral features.

Mid-infrared spectral analysis of glucose in subcutaneous interstitial fluid has been widely employed as a noninvasive alternative to the standard blood-glucose detection requiring blood-sampling via skin-puncturing, but improving the confidence level of such a replacement remains highly desirable. Here, we show that with an innovative metric of attributes in measurements and data-management, a high accuracy in correlating the test results of our improved spectral analysis to those of the standard detection is accomplished. First, our comparative laser speckle contrast imaging of subcutaneous interstitial fluid in fingertips, thenar and hypothenar reveal that spectral measurements from hypothenar, with an attenuated total reflection Fourier transform infrared spectrometer, give much stronger signals than the stereotype measurements from fingertips. Second, we demonstrate that discriminative selection of the spectral locations and ranges, to minimize spectral interference and maximize signal-to-noise, are critically important. The optimal band is pinned at that between 1000 ± 3 cm-1 and1040 ± 3 cm-1. Third, we propose an individual exclusive prediction model by adopting the support vector regression analysis of the spectral data from four subjects. The average predicted coefficient of determination, root mean square error and mean absolute error of four subjects are 0.97, 0.21 mmol/L, 0.17 mmol/L, respectively, and the average probability of being in Zone A of the Clark error grid is 100.00 %. Additionally, we demonstrate with the Bland and Altman plot that our proposed model has the highest consistency with portable blood glucose meter detection method.

Preparation and characterization of N-TiO2 photocatalyst with high crystallinity and enhanced photocatalytic inactivation of bacteria.

This study reports the synthesis, characterization and environmental applications of nitrogen doped TiO2 photocatalyst in the form of powder and film. N-TiO2 photocatalysts were synthesized via the hydrolysis of titanium tetraisopropoxide using urea as the nitrogen source. The crystalline structure, particle size and specific surface area of the resultant N-TiO2 nanoparticles were investigated by x-ray powder diffraction and the Brunauer-Emmett-Teller method. The results showed that a mixture of anatase and brookite phases was formed at pH 1 after annealing the powder at 450 ° C for 4 h, in contrast to a pure anatase phase at pH 3. UV-vis spectral characterization showed that the absorption region of the as-prepared N-TiO2 was extended to the visible light region. Stable sols could be achieved by controlling the molar ratio of water-to-titanium precursor and pH of the sols. During the photocatalytic test, in comparison to the standard commercial photocatalyst Evonik-Degussa P25 and home-made bare TiO2 nanoparticles, the N-TiO2 particles exhibited enhanced photocatalytic performance for degradation of methylene blue (MB) dye. The visible light induced photocatalytic inactivation of the obtained nanopowders and nanofilms on bacteria (Escherichia coli) was evaluated. The N-TiO2 nanomaterials showed higher bactericidal activity under visible light irradiation.

Effects of intrinsic defects on methanthiol monolayers on Cu(111): a density functional theory study.

Density functional theory calculations were used to examine the effects of intrinsic surface defects of Cu(111) on the adsorption of methylthiol (CH3SH). The examination covers both the initial non-dissociative adsorption and the subsequent dissociation reaction pathways to form intermediate and final reaction products. By comparing the most probable adsorption structures likely formed after the adsorption of CH3SH on Cu(111) with and without the presence of adatoms (Cu(ad)) and vacancies, this computational work offers new insights about the geometry and thermodynamic stability of these structures. Particularly, it reveals a new type of surface complexes having two CH3S bonding to one Cu(ad) (referred therein as CH3S-Cu(ad)-CH3S). In addition, this work also yields new reaction dynamics results on transition states and activation barriers. The results reveal that the presence of Cu(ad) indeed significantly changes the kinetics of adsorption and dissociation of CH3SH on Cu(111). The most kinetically favorable reaction pathway turns out to be that involving the formation of a special surface complex formed by one Cu(ad) plus two CH3S fragments from the dissociation of CH3SH, with the two S atoms located at the bridge sites of Cu(111). Finally, this work also gives simulated scanning tunneling microscopic images for the most important adsorption species in the course of the transition from CH3SH∕Cu(111) to CH3S∕Cu(111), which may stimulate future experimental studies of self-assembled monolayers on practical metal substrates such as thiols on copper.

Electrical transport along bacterial nanowires from Shewanella oneidensis MR-1.

Bacterial nanowires are extracellular appendages that have been suggested as pathways for electron transport in phylogenetically diverse microorganisms, including dissimilatory metal-reducing bacteria and photosynthetic cyanobacteria. However, there has been no evidence presented to demonstrate electron transport along the length of bacterial nanowires. Here we report electron transport measurements along individually addressed bacterial nanowires derived from electron-acceptor-limited cultures of the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1. Transport along the bacterial nanowires was independently evaluated by two techniques: (i) nanofabricated electrodes patterned on top of individual nanowires, and (ii) conducting probe atomic force microscopy at various points along a single nanowire bridging a metallic electrode and the conductive atomic force microscopy tip. The S. oneidensis MR-1 nanowires were found to be electrically conductive along micrometer-length scales with electron transport rates up to 10(9)/s at 100 mV of applied bias and a measured resistivity on the order of 1 Ω·cm. Mutants deficient in genes for c-type decaheme cytochromes MtrC and OmcA produce appendages that are morphologically consistent with bacterial nanowires, but were found to be nonconductive. The measurements reported here allow for bacterial nanowires to serve as a viable microbial strategy for extracellular electron transport.