Interfacial Kinetics Research Articles

3D reduced graphene oxide wrapped MoS2@Sb2S3 heterostructures for high performance sodium-ion batteries

Metal sulfides have been widely used as the anode materials of sodium-ion batteries (SIBs) due to their high theoretical capacity. However, their inherent low conductivity and irreversible volume expansion limit their electrochemical performance and application. To solve these problems, the MoS2@Sb2S3 heterostructure composites wrapped by 3D interconnected reduce graphene oxide (rGO) are prepared. The MoS2@Sb2S3 heterostructure accelerates the transfer of ions and electrons, and provides rich active sites, which facilitates electrolyte penetration and improves the interfacial reaction kinetics. Wrap 3D interconnected rGO networks around the porous MoS2@Sb2S3 composites to reduce the volume expansion of composite materials in the process of sodiumization and desodiumization, and ensure the structural stability. The theoretical calculation further supports the experimental results that the MoS2@Sb2S3/rGO heterojunction promotes the redistribution of different charge density and optimizes the adsorption energy of the composite for Na+, thus accelerating the electrochemical reaction kinetics. The MoS2@Sb2S3/rGO composite as the anode materials of SIBs can achieve a discharge specific capacity of 591.6 mAh g−1 at the second cycle with current density of 5 A g−1, and 162.1 mAh g−1 after 1100 cycles. High-rate capacities are achieved for SIBs (350.4 mAh g−1 @ 1 A g−1, 260.1 mAh g−1 @ 5 A g−1). This work provides a practical method for preparing anode materials of SIBs with excellent electrochemical performance.

Improving Electrocatalytic Activity of MoO3 for the Oxygen Evolution Reaction by Incorporation of Li Ions

Several polymorphs of MoO3 with different crystal and electronic structures provide many opportunities to find suitable electrocatalysts for water splitting hydrogen generation. So far, promising electrocatalytic activity for hydrogen evolution reaction (HER) has been found for α-MoO3 (orthorhombic), while the polymorph has shown a poor oxygen evolution reaction (OER) activity. In this work, it is found that the intrinsic OER activity of α-MoO3 is remarkably improved by incorporating guest ions of lithium-ion (Li+). α-MoO3 nanoparticles were deposited on a carbon fiber paper (α-MoO3/CFP) by chemical vapor transport and a subsequent lithiation process was applied to prepare lithiated α-MoO3/CFP (Li-α-MoO3/CFP), showing the robust η10 of 458 mV. The improved OER activity in the lithiated electrode is attributed to the incorporation of Li+ into the MoO3, which increases the electron carrier density and the corresponding electrical conductivity, thereby improving the interfacial charge transfer kinetics as well as activating a large number of ECSA.

Characterization of Mass Transfer within the Crystal-Solution Boundary Layer of l-Alanine {120} Faces Using Laser Interferometry during Growth and Dissolution.

Crystallization and dissolution are important processes to consider in drug development as well as many other industrial processes. Many current growth and dissolution models are based on bulk solution properties and do not implicitly consider concentration variation close to the crystal surface-solution interface and how this is mediated by solute diffusive mass transfer. Solution boundary layer thickness and concentration distribution, for the {120} crystal habit face of single crystals of l-alanine in saturated aqueous solutions during both growth and dissolution processes, is measured as a function of super/undersaturation using a Mach-Zehnder optical interferometer system. Further analysis allows determination of the diffusion coefficient and mass flux within the boundary layer as well as whether the processes are controlled by mass transfer or crystal interfacial kinetics. The measurement of this study revealed that the {120} face was not saturated at its surface during growth or dissolution meaning both processes were somewhat limited by their crystal interfacial kinetics. Growth was limited by crystal interfacial kinetics at all supersaturations to the same degree, whereas dissolution had a mixed dependency on crystal interfacial kinetics and mass transfer at lower undersaturations becoming more limited by mass transfer at higher undersaturations. Boundary layer thickness increased with super/undersaturation but to a lesser degree than the increase in the concentration difference between the crystal surface and bulk solution leading to a higher mass flux of solute molecules through the boundary layer. At the same relative super/undersaturation mass flux of solute molecules was faster during dissolution which was concurrent with its increased surface to bulk solution concentration difference and boundary layer thickness.

Ready-to-use interactive dual-readout differential lateral flow biosensor for two genotypes of human papillomavirus

Ready-to-use in vitro diagnosis of multiple genotypes is vital for the prevention and treatment of cervical cancer. Herein, a paper-film-based interactive dual readout differential lateral flow biosensor is proposed to simultaneously assay two high-risk types of human papillomavirus (HPV) within the body-fluid. The CuCo2S4/ZnIn2S4 heterostructure is fabricated on the paper-film compound chip with high thermostability, and surface sulfur vacancy is introduced by mild annealing treatment to endow unexceptionable photoexcitation activity, such structure can be served as an initial energy harvester and converter. With the assistance of differential channels, the dual-target-propelled self-assembly of annular DNA and the cleavage activity of CRISPR-Cas12a are stepwise activated by sequential solution transfer. Accordingly, the input and release of polydopamine-coated gold nanoparticles with photothermal/photoelectric characteristic were implemented. The fabricated biosensor not only realized intelligent thermal-response without large instruments, but also actuated dynamic interfacial charge separation and transfer kinetics to further transmit photoelectric-signal, resulting in desirable interactive dual-signal with low limit-of-detection (0.21 pM for HPV-18 and 42.92 pM for HPV-16). Thanks to the sophisticated design of differential lateral flow paper-film compound chip and interactive dual-signal amplification strategy, sensitive detection of two HPV genotypes is realized, which provides a promising candidate for home medical intelligent diagnosis.

A Multifunctional Electrolyte Additive With Solvation Structure Regulation and Electrode/Electrolyte Interface Manipulation Enabling High‐Performance Li‐Ion Batteries in Wide Temperature Range

AbstractImproving the tolerance of Li‐ion batteries (LIBs) to extreme temperatures and climates worldwide is vital to their global uptake. However, LIBs call for more strict requirements for the key components when operated in a wide temperature range, especially synchronously desirable interfacial kinetics and thermal stability. Here, a novel multifunctional electrolyte additive,N‐tert‐butyl‐2‐thiophenesulfonamide (NTSA), to fabricate stable LIBs under wide‐temperature conditions, is reported. The Li‐ion solvation structure in the electrolyte is regulated and involves less coordinated solvents (particularly fluoroethylene carbonate), leading to superior Li+transportation. The effective NTSA additive is preferentially decomposed to form a uniform electrode/electrolyte interface with abundant multiphase inorganic LiF, Li3N, and LiS species simultaneously on the cathode and anode surface. The resulting inorganic‐rich interface can not only boost the interfacial Li‐ion transfer kinetics at low temperatures but also protect the active material and enhance the thermal stability of the interface and LIB devices at high temperatures. By adopting the NTSA‐containing electrolyte, LiCoO2||ω‐Li3V2O5LIBs can be stably cycled in a wide temperature range between −30 °C and 80 °C, delivering a high capacity of ≈100.1 mAh g−1(0.2 A g−1) at −20 °C and high capacity retention of 94.5% after 200 cycles (0.5 A g−1) at 55 °C.

Interfacial Engineering of Na3V2(PO4)2O2F Cathode for Low-Temperature (-40 °C) Sodium-Ion Batteries.

Na3V2(PO4)2O2F (NVPOF) is considered a promising cathode material for sodium-ion batteries (SIBs) on account of its attractive electrochemical properties such as high theoretical capacity, stable structure, and high working platform. Nevertheless, the inevitable interface problems like sluggish interfacial electrochemical reaction kinetics and poor interfacial ion storage capacity seriously hinder its application. Construction of chemical bonding is a highly effective way to solve interface problems. Herein, NVPOF with interfacial V-F-C bonding (CB-NVPOF) is developed. The CB-NVPOF cathode exhibits high rate capability (65 mA h g-1 at 40C) and long-term cycling stability (a capacity retention of 77% after 2000 cycles at 20C). Furthermore, it shows impressive electrochemical performance at temperatures as low as -40 °C, delivering a capacity of 56 mA h g-1 at 10C and a capacity retention of ∼80% after 500 cycles at 2C. The interfacial V-F-C bond engineering significantly advances the electronic conductivity, Na+ diffusion, as well as interface compatibility at -40 °C. This study provides a novel idea for improving the electrochemical performance of NVPOF-based cathodes for SIBs aiming for low-temperature applications.

(n, m) Distribution of Single-Walled Carbon Nanotubes Grown from a Non-Magnetic Palladium Catalyst

Non-magnetic metal nanoparticles have been previously applied for the growth of single-walled carbon nanotubes (SWNTs). However, the activation mechanisms of non-magnetic metal catalysts and chirality distribution of synthesized SWNTs remain unclear. In this work, the activation mechanisms of non-magnetic metal palladium (Pd) particles supported by the magnesia carrier and thermodynamic stabilities of nucleated SWNTs with different (n, m) are evaluated by theoretical simulations. The electronic metal-support interaction between Pd and magnesia upshifts the d-band center of Pd, which promotes the chemisorption and dissociation of carbon precursor molecules on the Pd surface, making the activation of magnesia-supported non-magnetic Pd catalysts for SWNT growth possible. To verify the theoretical results, a porous magnesia supported Pd catalyst is developed for the bulk synthesis of SWNTs by chemical vapor deposition. The chirality distribution of Pd-grown SWNTs is understood by operating both Pd-SWNT interfacial formation energy and SWNT growth kinetics. This work not only helps to gain new insights into the activation of catalysts for growing SWNTs, but also extends the use of non-magnetic metal catalysts for bulk synthesis of SWNTs.

4.2V polymer all-solid-state lithium batteries enabled by high-concentration PEO solid electrolytes

Polyethylene oxide (PEO) solid electrolytes (SEs) are practicable in all-solid-state lithium batteries (ASSLBs) with high safety for driving electric vehicles. However, the low oxidative decomposition potential (below 4 V) of normal PEO SEs rules out high-voltage (≥4.2 V) cathodes in PEO-based ASSLBs with sacrificed energy densities. Herein, high-concentration PEO SEs (EO:Li+ ≤ 6:1) possessing high oxidation potentials (>5 V vs. Li/Li+) are designed based on concentrated-salt chemistry with oxidation potential surging incessantly with increasing the degree of coordinated EO. Thereby, double-layered heterogenous SEs with PEO(EO:Li=4:1) on the cathode side and PEO(EO:Li=16:1) on the anode side are designed to resist oxidation and bate interfacial impedance. Coupled with 4.2 V-class LiCoO2 and LiNi0.6Co0.2Mn0.2O2, the ASSLBs using heterogenous SEs exhibit enhanced stable cycling performances when charged to 4.2 V and 4.4 V at 60°C. As revealed by the Wagner-type model and Raman spectra, high-concentration PEO SE could suppress the interfacial degradation kinetics, the production of electronic conduction in the cathode electrolyte interphase (CEI) and the irreversible phase-change of LiCoO2 to Co3O4. All these contribute to the improved electrochemical performance of PEO/LiCoO2 system with high-volage, offering a potential pathway toward high-voltage stable polymer electrolytes for high-energy-density lithium batteries.

Interfacial Adsorption Kinetics of Methane in Microporous Kerogen.

Rapid declines in unconventional shale production arise from the poorly understood interplay between gas transport and adsorption processes in microporous organic rock. Here, we use high-fidelity molecular dynamics (MD) simulations to resolve the time-varying adsorption of methane gas in realistic organic rock samples, known as kerogen. The kerogen samples derive from various geological shale fields with porosities ranging between 20% and 50%. We propose a kinetics sorption model based on a generalized solution of diffusive transport inside a nanopore to describe the adsorption kinetics in kerogen, which gives excellent fits with all our MD results, and we demonstrate it scales with the square of the length of kerogen. The MD adsorption time constants for all samples are compared with a simplified theoretical model, which we derive from the Langmuir isotherm for adsorption capacitance and the free-volume theory for steady, highly confined bulk transport. While the agreement with the MD results is qualitatively very good, it reveals that, in the limit of low porosity, the diffusive transport term dominates the characteristic time scale of adsorption, while the adsorption capacitance becomes important for higher pressures. This work provides the first data set for adsorption kinetics of methane in kerogen, a validated model to accurately describe this process, and a qualitative model that links adsorption capacitance and transport with the adsorption kinetics. Furthermore, this work paves the way to upscale interfacial adsorption processes to the next scale of gas transport simulations in mesopores and macropores of shale reservoirs.

Interfacial enzyme kinetics reveals degradation mechanisms behind resistant starch

The digestive resistance of so-called resistant starch (RS) provides an important nutritional principle. However, as yet the mechanisms underlying digestive resistance of the granular starches are not well described. We address this problem by employing a novel enzyme kinetics approach, which in contrast to conventional enzyme kinetics takes the interfacial nature of the enzyme reaction into account. Structurally different starch granules with different amylose contents were modified by the hydrolytic enzyme glucoamylase (GA). Kinetic-, adsorbtion-, imaging-, particle size-, and spectroscopic data combinedly revealed important origins of hydrolytic resistance of high-amylose starch. Our data demonstrate that amylose restricted the enzymatic catalysis efficiency on starch granules chiefly by providing less hydrolytic effective attack sites for the enzyme at granular surface. Specifically, the total binding sites (adsΓmax) (20.9 nmol/g) on starch with 0% amylose content (AC) were almost all effective attack sites (kinΓmax) (20.2 nmol/g). At 26% AC, the binding sites on the granules decreased to 13.9 nmol/g, and attack sites decreased to 7.4%. At 72% AC, the binding sites were only slightly reduced to 11.2 nmol/g, however, the attack sites were remarkably decreased to 2.6 nmol/g. Beyond the initial catalytic events, i.e., for further degraded granules, the binding and catalysis efficiency differed notably for the three starch types. At 0% AC, both binding and attack increased demonstrating increased hydrolytic susceptibility of the granules. At 26% AC only binding increased, while attack was unchanged. Interestingly, at 72% AC, binding increased, while attack deceased notably with hydrolysis time, demonstrating decreased efficiency of interfacial catalysis during the hydrolysis process.

Decoupling Effects of Electrostatic Gating on Electronic Transport and Interfacial Charge-Transfer Kinetics at Few-Layer Molybdenum Disulfide.

The electronic properties of electrode materials play a crucial role in defining their electrochemical behavior in energy conversion and storage devices. The assembly of van der Waals heterostructures and fabrication into mesoscopic devices enable the dependence of an electrochemical response on electronic properties to be systematically interrogated. Here, we evaluate the effect of charge carrier concentration on heterogeneous electron transfer at few-layer MoS2 electrodes by combining spatially resolved electrochemical measurements with field-effect electrostatic manipulation of band alignment. Steady-state cyclic voltammograms and finite-element simulations reveal a strong modulation of the measured electrochemical response for outer-sphere charge transfer at the electrostatic gate voltage. In addition, spatially resolved voltammetric responses, obtained at a series of locations at the surface of few-layer MoS2, reveal the governing role of in-plane charge transport on the electrochemical behavior of 2D electrodes, especially under conditions of low carrier densities.

Anionic Effects on Li-Ion Activity and Li-Ion Intercalation Reaction Kinetics in Highly Concentrated Li Salt/Propylene Carbonate Solutions

Certain highly concentrated electrolytes (HCEs) enhance the charge-transfer reaction rate at the electrode/electrolyte interface in Li-ion batteries. The solvation structure of Li+ in HCEs significantly affects the electrochemical interfacial reaction kinetics. However, the effects of different anions on these kinetics have not yet been fully understood. Therefore, in this study, we investigated the effects of anionic species on the liquid structure and electrochemical reactions of HCEs composed of various Li salts and propylene carbonate (PC). Raman spectra revealed that both PC and anions were coordinated to Li+ ions in HCEs and that the concentration of uncoordinated (free) PC changed depending on the anionic species. Consequently, the activity of Li+ in the electrolyte changed depending on the anionic species. The use of Li salts with weakly Lewis basic anions increased the activity of Li+ and decreased the concentration of free PC in HCEs. The activity of Li+ in the electrolyte significantly affected the Li+ intercalation/deintercalation reaction rate of the LiCoO2 thin-film electrode. Electrochemical impedance spectroscopy revealed that the interfacial reaction rate of LiCoO2 was enhanced in the HCEs with anions having weaker Lewis basicity owing to the higher Li+ ion activity.

Scanning Electrochemical Microscope Studies of Charge Transfer Kinetics at the Interface of the Perovskite/Hole Transport Layer

Interfacial carrier transfer kinetics is critical to the efficiency and stability of perovskite solar cells. Herein, we measure the regeneration rate constant, absorption cross-section, reduction rate constant, and conductivity of hole transport layered perovskites using scanning electrochemical microscopy (SECM). The SECM feedback revealed that the regeneration rate constant, absorption cross-section, and reduction rate constant of the nickel oxide (NiO) layer perovskite layer are higher than those of the poly (3,4-ethyenedioxythiophene)-poly (styrenesulfonate) layered perovskite. Also, at a specific flux density ( J h v ), the value of the regeneration rate constant (keff) in both blue and red illuminations for the NiO/CH3NH3PbI3 film is significantly higher than in both PEDOT: PSS/CH3NH3PbI3 and FTO/CH3NH3PbI3 films. The difference in keff between layered and nonlayered perovskite conforms to the impact of the hole conducting layer on the charge transfer kinetics. According to the findings, SECM is a powerful approach for screening an appropriate hole transport layer for stable perovskite solar cells.

Interfacial Polymerization Kinetics of Polyurea Microcapsules Formed Using Hexamethylene Diisocyanate Biuret Low Viscosity Isocyanate

AbstractFor cosmetic industrial applications, polyurea microcapsules were formed by using hexamethylene diisocyanate biuret low viscosity (HDB‐LV) and three different amines: ethylenediamine (EDA), guanidine (GUA), and hexamethylenediamine (HMDA). Toluene droplets containing dissolved HDB‐LV were formed by an oil‐in‐water emulsion before being poured into a water phase containing the required excess of amine. The pH of the aqueous phase was fitted through time to calculate the kinetic constant k' and the diffusion constant DB through the polyurea shell when possible. At 60 °C, EDA and HMDA follow a pure kinetic regime, whereas GUA follows a combination of kinetic and diffusion regimes. The presented kinetic data shows that HDB‐LV is a promising nontoxic isocyanate for cosmetic encapsulation.

Enhanced Photoelectrochemical Water Oxidation on BiVO4 Photoanodes Functionalized by Bimetallic Dicyanamide Molecular Catalysts

A novel hybrid structure of bimetallic dicyanamide decorated BiVO4 is developed via a simple method to accelerate interfacial water oxidation kinetics. Two types of bimetallic dicyanamides, CoNi(dca)2 and CoFe(dca)2, are coated on BiVO4 photoanodes and are found to exhibit far more enhanced PEC performance than Co(dca)2 or Ni(dca)2 as cocatalysts. The successful deposition of metal dicyanamides on BiVO4 photoanodes is confirmed by physical characterizations including X-ray photoelectron spectroscopy (XPS). The optimized Co0.9Ni0.1(dca)2/BiVO4 photoanode exhibits the highest photocurrent density of 2.58 mA/cm2 at 1.23 V vs. RHE under 100 mW/cm2 AM 1.5 G irradiation, which is 2.5 times that of bare BiVO4. The substantial enhancement of PEC performance can be ascribed to the advantageous interfacial charge transfer and improved charge injection efficiencies. This work presents a feasible strategy using different types of bimetallic dicyanamides to design a modified BiVO4-based photoanode system for enhanced water oxidation efficiency.

New insights into high-rate and super-stable aqueous zinc-ion batteries via the design concept of voltage and solvation environment coordinated control

As the great potential host materials, the application of low-valent vanadium-based compounds for aqueous zinc-ion batteries are usually suffered from the insufficient storage capability and cycle performance. In this work, a unique voltage and solvation environment coordinated control strategy was developed to unlock the MXene derived VNxOy/C heterostructure as robust host applied for aqueous zinc-ion batteries. As the results indicated, such VNxOy/C can be completely converted to the new phase of Zn3(OH)2V2O7·2H2O when the cut-off voltage was controlled at 0.2–2.0 V. Moreover, unlike the mechanism of H+/Zn2+ co-insertion/extraction accompanied with the by-product formation in the electrolyte of pure H2O system, it was demonstrated that the introduction of hydrophilic polyethylene glycol (PEG) into electrolyte enables tailoring the solvation environment, forming the proton shielding to eliminate the blocking effect of by-products on interfacial transport kinetics and storage reversibility of the electrode, thus realizing controllable Zn2+-dominant insertion/extraction mechanism. Unexpectedly, such low-valent VNxOy/C electrode under the coordinated control of voltage and solvation environment enables achieving a significantly enhanced rate capability and ultralong cycle lifespan, which can retain the specific capacities of 369.4 and 112.7 mAh g−1 after 2000 cycles at 0.5 A g−1 and 14,200 cycles at 10 A g−1, respectively. Such novel and efficient avenue for the development of low-valent cathode material is expected to deepen the understanding of the construction of efficient energy storage systems including but not limited to aqueous zinc-ion batteries.

Localized Recrystallization of a Lithium-Metal Anode during Fast Stripping in High-Activity Liquid Electrolytes.

The lithium-metal anode is one of the most promising candidates for "beyond-lithium-ion" batteries thanks to its high specific capacity and low negative electrochemical potential. However, the electrode-electrolyte interface instability hinders its commercialization in rechargeable batteries. During cycles of charging and discharging, the lithium-metal anode is electrochemically plated and stripped along with the morphological evolution, which determines the cycling performance. In this work, with a phase-field model, we computationally characterize the morphological evolution dynamics during the plating and stripping steps at the lithium-metal-electrolyte interface. Our model is valid in a wide range of lithium concentrations in liquid electrolytes by incorporating nonidealities of electrolyte solutions into the interfacial reaction kinetics. Intriguingly, at fast stripping, i.e., high discharging overpotential, we observe an unexpected localized recrystallization phenomenon in high-lithium-ion-concentration valley regions. This recrystallization phenomenon mitigates the overall reaction rate heterogeneity and provides a potential approach to improving the morphological stability. Furthermore, we systematically investigate the correlation between the recrystallization phenomenon and lithium-ion activity and draw a simplified phase diagram for the overpotential-dependent recrystallization.

Structure and interface engineering on polypyrrole-deposited conductive paper originating from nature wood enables high performance flexible all-solid-state supercapacitors

Paper is an ideal substrate for manufacturing flexible electrodes because of its lightweight, inherent mechanical flexibility, and unique structure. However, the traditional bottom-up method of manufacturing paper-based electrode is time-consuming and the active material is easy to fall off. Here, we report a polypyrrole-deposited conductive paper (PCP), which is fabricated by chemical treatment, mechanical compression, and chemical polymerization of natural wood. The post densification process eliminates the vertical arrangement of wood cell cavities, and the formed wood fiber/multi-walled carbon nanotubes hybrid conductive network has high flexibility. The further deposited polypyrrole (PPy) conductive layer can effectively boost the ion transport between electrode/electrolyte interface and increase the active center of interface reaction. Based on the well-designed electrode structure and good interfacial reaction kinetics, the resulting PCP with a PPy mass loading of only 2.4 mg·cm−2 indicates a high areal capacitance of 275.8 mF cm−2 at 20 mV·s−1 and good cycling stability. All-solid-state symmetric supercapacitor exhibits capacitance of 308.3 mF·cm−2. This structure and interface design concept show a promising method for preparing high-performance and scalable biomass-based flexible electronic devices.

Kinetic Difference in Water Photooxidation between TiO2 and WO3 Electrodes by Rate Law Analysis

The photocarrier interfacial kinetics is often considered to be a bottleneck for water photooxidation on semiconductors and has attracted extensive attention in recent years. Although tremendous efforts have been devoted into the kinetic study for a certain semiconductor, there are few works focused on the dynamic differences in water oxidation between various kinds of semiconductors. In this study, the kinetics of water oxidation on WO3 and TiO2 electrodes was investigated by a combination of photoelectrochemical techniques and then compared using the electrodes’ rate law. It was found that the water oxidation on WO3 is faster than the that of TiO2 electrodes under the same surface hole density and the basic origin for this kinetic difference is attributed to greater charger transfer rate constant (kct). The greater kct is due to the fact that the WO3 electrodes have a smaller Helmholtz layer capacitance (CH), a larger space charge layer capacitance (CSC), and a greater charge transfer rate constant at flatband potential (kct0). These finding provide a better understanding of the photocarrier transfer dynamics and may enlighten rational design on exploiting the metal oxide semiconductors to achieve a higher solar conversion efficiency.

Effect of Mo2C-functionalized electrode interface on enhancing microbial cathode electrocatalysis: Beyond electrochemical hydrogen evolution

Mo2C has recently been introduced into microbial cathode electrocatalysis due to its well-known catalytic activity for hydrogen evolution reaction (HER), but a low electrode potential (i.e., a high energy input) is required usually. However, in the range of potential where HER cannot occur, its effect on microorganism/cathode interfacial kinetics remains unknown. Herein, an active Mo2C interface is constructed on conventional carbon cloth electrode to investigate its impact on electric-driven fumarate reduction by a typical electroactive microorganism (Shewanella oneidensis MR-1) at a potential of −0.36 V (vs. standard hydrogen electrode) that cannot meet the HER requirement. The Mo2C-functionalized electrode achieves a greatly increased current consumption density of ∼0.041 mA cm−2, about three times that of the control, indicating a faster fumarate reduction rate. This substantially proves that the enhancement of microbial electrocatalytic kinetics at Mo2C-functionalized interface is not confined to the induced hydrogen evolution. By analyzing its interaction with extracellular electron transfer mediators (e.g., c-type cytochromes and riboflavin), a robust inward extracellular electron transfer process based on the rapid electrochemical reaction of riboflavin at the Mo2C-functionalized interface is elaborated. This work provides a new understanding of the mechanism by which the nanostructured Mo2C interface enhances microbial cathode electrocatalysis.