Lower Charge Transfer Resistance Research Articles

Vertically aligned ReS2 on MOF deorived CoS2–C hybrid as core-shell catalyst for promoting overall water splitting

The rational design of a core-shell structured electrocatalyst is important to improve the efficiency of electrocatalytic hydrogen production through water splitting. Herein, the catalyst is composed of rhenium disulfides (ReS2) vertically grown on cobalt sulfides/carbon hybrid by hydrothermal and activation treatment (CoS2–C@ReS2/CFP). The core-shell structure is constructed by sulfurizing the cobalt-based metal-organic framework, preventing the restacking of the ReS2 nanosheet, exposing more active sites, and facilitate electrolyte ion diffusion. Moreover, the CoS2–C@ReS2/CFP catalyst shows exceptional performance during the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) process in an alkaline electrolyte. At ·10 mA cm−2, the overpotentials of the CoS2–C@ReS2/CFP catalyst are 85 and 257 mV during the HER and OER processes with the small Tafel slope, low charge transfer resistance and exceptional catalytic stability. The combination of the CoS2 core and ReS2 shell is designed to adjust the adsorption energy of water molecules, promoting water dissociation, and enhancing the catalytic activity of CoS2–C@ReS2/CFP catalyst. This work provides an efficient strategy for developing the core-shell structured catalysts, potentially advancing the practical application into water splitting for hydrogen production.

Electrochemical analysis of hydrothermally synthesized 2D/1D WS2/WO3 nanocomposites for solar cell application

The nanocomposites of transition metal dichalcogenides (TMDs) and metal oxides (MOs) show enhanced properties for photovoltaic applications. In view of this, we have reported the synthesis of a series of tungsten sulphide/tungsten oxide (WS2/WO3) nanocomposites, wherein tungsten to sulphur ratio has been gradually varied to achieve the optimized properties for photovoltaic applications. The samples were analysed for structural, optical, morphological, microstructural, electrokinetic and electrochemical properties by various characterization techniques. Integrating the properties of WS2 and WO3 provided enhanced properties in the form of wider absorbance range, optimized band gap, better colloidal stability and reduced charge transfer resistance. The as-synthesized nanocomposites showed the absorbance in UV & visible regions with the band gap varying from 1.54 eV to 1.68 eV. The zeta potential measurement showed high colloidal stability of some of the nanocomposites with values < −30 mV along with their uniform distribution. The electrochemical behaviour of the samples has been studied by cyclic voltammetry and potentio electrochemical impedance spectroscopy in which prominent redox peaks and diffusive behaviour have been observed. The impedimetric properties revealed the presence of Warburg diffusion which shows their suitability for photovoltaic applications. The sample with least sulphur to tungsten molar ratio was observed to have lowest charge transfer resistance and highest exchange current density of 198.8 μA. The samples with molar ratio nearly unity have high charge transfer resistance and low exchange current density. The present work reveals that the optical, electrokinetic and electrochemical properties of WS2/WO3 nanocomposites can be optimized for solar cell application by controlling the precursors’ concentration.

Achieving Exceptional Volumetric Desalination Capacity Using Compact MoS2 Nanolaminates.

Capacitive deionization (CDI) has emerged as a promising technology for freshwater recovery from low-salinity brackish water. It is still inapplicable in specific scenarios (e.g., households, islands, or offshore platforms) due to too low volumetric adsorption capacities. In this study, we report a high-density semi-metallic molybdenum disulfide (1T'-MoS2) electrode with compact architecture obtained by restacking of exfoliated nanosheets, which achieved high capacitance up to ∼277.5 F cm-3 under an ultrahigh scan rate of 1000mV s-1 with a lower charge-transfer resistance and nearly ten-fold higher electrochemical active surface area than the 2H-MoS2 electrode. Furthermore, 1T'-MoS2 electrode demonstrates exceptional volumetric desalination capacity of 65.1 mgNaCl cm-3 in CDI experiments. Ex-situ X-ray diffraction (XRD) reveal that the cation storage mechanism with the dynamic expansion of 1T'-MoS2 interlayer to accommodate cations such as Na+, K+, Ca2+, and Mg2+, which in turn enhances the capacity. Theoretical analysis unveils that 1T' phase is thermodynamically preferable over 2H phase, the ion hydration and channel confinement also play critical role in enhancing ion adsorption. Overall, this work provides a new method to design compact two-dimensional layered nanolaminates with high volumetric performance for CDI desalination. This article is protected by copyright. All rights reserved.

Flexible Ni‐Based Bimetallic Spinel Oxide (NiM2O4, M = Mn, Fe, Co) Electrodes for Supercapacitor Applications

Herein, the single‐phase Ni‐based bimetallic spinel oxide (NiM2O4, M = Mn, Fe, Co) nanoparticles are successfully synthesized by sol–gel method and coated on a carbon cloth substrate to form flexible electrodes for supercapacitor applications. The effects of transition metal activity, calcination temperature, surface, and textural properties on the electrochemical properties of spinel electrode materials are demonstrated. It is found that lowering the calcination temperature results in a decrease in crystallite size and particle size, leading to an increase in surface area and pore volume. X‐Ray absorption spectroscopy reveals the presence of Mn2+/3+, Fe2+/3+, and Co2+/3+ in materials. According to the electrochemical studies, NiMn2O4 electrode in Na2SO4 electrolyte exhibits electrical double‐layer capacitance behavior, while NiFe2O4 and NiCo2O4 electrodes in KOH electrolyte exhibit pseudocapacitive behavior. All electrode materials have low solution resistance and charge transfer resistance. NiCo2O4 provides the highest specific capacitance (85.60 F g−1 at 2.5 A g−1) followed by NiFe2O4 and NiMn2O4. It seems likely that the high electrochemical activity of Co2+/3+ and small particle size of NiCo2O4 nanoparticles play an important role in improving the redox process and charge transfer, which may enhance the electrochemical performance of this electrode material.

Schottky junction-mediated carrier separation in BiOBr/Ti3C2Tx van der Waals heterojunction photocatalyst for increased removal of Cr(VI) under visible-light

The photocatalytic removal of pollutants can integrate efficient solar energy utilization with wastewater treatment. Herein, we report a simple strategy to construct BiOBr/Ti3C2Tx composite photocatalysts consisting of self-assembled van der Waals (vdw) heterojunction structures containing Schottky junctions. The vdW interaction between BiOBr and Ti3C2Tx and the structural stability of the catalysts were validated by density functional theory (DFT) calculations and an ab initio molecular dynamic simulation (AIMD). Compared to BiOBr, the BiOBr/Ti3C2Tx composites exhibited an enhanced light absorption capability and photocurrent response, along with a lower carrier recombination rate and charge-transfer resistance. The BiOBr/Ti3C2Tx activity for the photoreduction of hexavalent chromium (Cr(VI)) under visible-light irradiation considerably surpassed that of the original BiOBr (53.9%). Using the BTC-0.8 catalyst (with a Ti3C2Tx: BiOBr mass ratio of 0.8%) optimal reduction efficiency (94.0%) for Cr(VI) with a reaction rate approximately 3.5 times that of pure BiOBr. The BTC-0.8 catalyst was viable over a wide pH range and maintained an 83.9% photoreduction rate after four cycling experiments. The exceptional photocatalytic ability of BiOBr/Ti3C2Tx was achieved because Ti3C2Tx served as an electron injection layer that separated photogenerated carriers. The Schottky junction constructed within the BiOBr/Ti3C2Tx vdW heterojunctions suppressed electron backflow, promoting carrier separation. The excellent photocatalytic performance and strong cyclic stability of BiOBr/Ti3C2Tx demonstrated the considerable application potential of this photocatalyst.

Photocatalytic activity and electrochemical properties of a ternary-based-TiO2 nanocomposite

A TiO2 photocatalyst modified with g-C3N4 and different wt% of CuO, is performed via hydrothermal method. The structural, morphological and spectroscopic characterizations are carried out. The ternary composite, g-C3N4/CuO/TiO2, exhibits greater photocatalytic activity than CuO/TiO2. The highest degradation of Levofloxacin reaches 99% and 44%, after 10 and 60 min UV irradiation over ternary and binary composites for 20 wt% of CuO, respectively, with a concentration of 5.10−3 g/L of LEVO and a photocatalyst mass of 2.10−2 g. The stability of g-C3N4/CuO/TiO2 is confirmed allowing its reuse for five successive cycles with a longer treatment time. Under solar irradiation, the degradation yield of Levo using g-C3N4/CuO/TiO2 is 100% after only 20 min. The as-synthesized nanocomposite present interesting electrochemical properties. In the medium-frequency region, the diameter of the semicircle for the g-C3N4/CuO/TiO2 electrode is much smaller than that of the CuO/TiO2 electrode, indicating a lower charge-transfer resistance.

Compositional alteration of low dimensional nickel sulfides under hydrogen evolution reaction conditions in alkaline media

Developing cost-effective electrodes for electrochemical water splitting with minimal kinetic losses remains a primary challenge in water electrolysis. Nickel-based dichalcogenides, particularly sulfides, have emerged as promising candidates for the hydrogen evolution reaction (HER). However, the stability of various nickel sulfide (NixSy) phases under cathodic potentials in alkaline electrolytes is subject to debate. In this study, we investigate the HER activity and durability of both 2-dimensional (2D) and 3-dimensional (3D) NixSy nanostructures with diverse chemical compositions. Through cross-correlation analysis of spectroscopic and electrochemical characterization data, we elucidate the transformation behavior of these materials under operating conditions. Our findings reveal that NiS2 tends to undergo conversion to nickel hydroxide (Ni(OH)2), while Ni-rich phases like Ni3S4 and NiS exhibit greater stability. Furthermore, we demonstrate that in 3D nanostructures, the initial formation of a protective hydroxide layer on the surface inhibits further sulfide transformation. This nickel sulfide/hydroxide composite shows an improved HER activity with lower onset potential (−0.25 V), Tafel slope (105 mV s−1), and charge transfer resistance (17.3 Ω).

Electrochemical detection of antimalarial drug (Amodiaquine) using Dy-MOF@MWCNT composites to prevent erythrocytic stages of plasmodium species in human bodies

Herein, we report on fabrication of dysprosium-based metal–organic framework (Dy-MOF)@multiwalled carbon nanotubes (MWCNT) composites modified with glassy carbon electrode (Dy-MOF@MWCNT/GC) as a working electrode for Antimalarial drug detection. Dy-MOF@MWCNT composites was prepared by sonochemical process along with ultrasonication. The composite structure, phase purity, morphology and composition of the composites were confirmed by X-ray diffraction, Scanning electron microscope, and X-ray photoelectron spectroscopy. Further, Dy@MWCNT composites were deposited on a glassy carbon electrode by drop casting method, and used as an electrode material to efficiently detect Amodiaquine (ADD) by electrochemical techniques such as CV and DPV. The as-prepared Dy@MWCNT composite material showed the oxidation peak current of ADD to be ∼ 60 % higher than other unmodified GC electrodes and showed a low charge transfer resistance (R ct) of 24 Ω. The Dy@MWCNT provided a broad linear range of 0.4 to 20 µM with a limit of detection of 0.377 μM and sensitivity of 1.817 μA.μM−1 for the detection of ADD. According to the pH study, the amount of electrons and protons involved in the electrochemical processes of ADD was calculated and a plausible mechanism for ADD electro-oxidation was proposed. Thus, the prepared sensor exhibited practical usefulness by determining the ADD drug in human urine samples. Hence, the results shows that the Dy@MWCNT- modified sensor has good electrocatalytic activity for the redox of ADD.

One‐Step Synthesis of Phase‐Controlled Co2P Nanoparticles as an Electrocatalyst for Hydrogen Evolution Reaction

AbstractCobalt phosphides have been investigated as potentially useful electrocatalysts for accelerating hydrogen evolution. Cobalt phosphide electrocatalysts are synthesized in a single step at varied phosphating temperatures (350, 400, 450 °C) via the gas phase approach. Synthesized at a phosphating temperature of 350 °C, Co2P (CP‐350) transforms into a mixed phase that contains both Co2P and CoP (CP‐400 and CP‐450) as the phosphating temperature goes up which is confirmed by XRD. CP‐350, CP‐400, and CP‐450 exhibited overpotentials of 181, 270, and 293 mV respectively with Tafel slopes of 112, 146, and 175 mV/dec. In contrast to CP‐400 and CP‐450, CP‐350 revealed superior hydrogen evolution reaction (HER) performance and stability for up to 12 h due to its pure phase (Co2P), high surface area (151 m2/g), and high electrochemical surface area (7.02 cm2) with low charge transfer resistance. According to our work, changing the phase and active surface area of transition metal phosphide catalysts can greatly increase their HER catalytic efficiency.

Effect of Sm dopant on electrocatalytic activity of AgNbO3 perovskite fabricated by sonication method for Oxygen Evaluation Reaction (OER)

Excessive reliance on fossil fuels causes a variety of difficulties and the use of efficient electrocatalysts material has exhibited significant attention for high electrocatalytic activity. Most transition metal oxide materials performance can be enhanced by the incorporation of metals for OER activity. This work presents the synthesis of samarium (Sm) doped silver niobium oxide (AgNbO3) was achieved using sonication techniques. An electrocatalyst, Sm-doped AgNbO3, has shown promising results for oxygen evolution reaction (OER) in alkaline medium with a significant increase in active sites, enhanced electrical conductivity and improved stability. The Sm-doped AgNbO3 electrocatalyst exhibits overpotential of 203 mV and Tafel slope of 35.22 mV dec−1 for OER activity at current densities of 10 mA cm−2. By utilizing, electrochemical surface area (ECSA), the Sm-doped AgNbO3 electrocatalyst exhibited higher ECSA values of 1009 cm−2 with a higher roughness factor of 2008.60. Further, observations of low charge transfer resistance value (Rct = 0.17 Ω) along with a durability of 50 h, indicate that this material is highly efficient and long-lasting as an electrocatalyst for energy conversion systems.

Development of Nd doped AlFeO3 electrode material for supercapacitor applications

The development of metal oxides nanoscale structures with enhanced chemically active surfaces, faster ion/charge transport kinetics with shorter ion-diffusion paths is demand in the field of supercapacitor. The issue of transition metal oxides has been successfully resolved through the utilization of metal doping, which concurrently enhances surface area, accelerates ion migration and enhances thermal and structural stability. The Nd doped AlFeO3 electrode substance fabricated hydrothermal process for electrochemical properties. The different analytical tools determined physical and electrochemical characteristics of prepared electrode material. Nd@AlFeO3 electrode material demonstrates specific capacitance of 1326 F/g at 1 A/g measured from galvanostatic charging/discharging plot which maintains remarkable stability after 5000th cycles. The Nyquist plot determines lower charge transfer resistance of Nd@AlFeO3 electrode material (1.15 Ω). The Nd@AlFeO3 electrode material exhibited improved electrochemical properties which makes it promising candidate for integration into supercapacitor devices.

High-efficient water splitting over an in-situ growth novel electrocatalyst of metal-organic framework-based nanostructures

Metal-organic frameworks (MOFs) as emerging material have drawn much attention to apply to the field of water splitting. In this paper, layered NiFe-MIL-53 and nanoflower-like CoFe-MOF-74 were sequentially grown on nickel foam through two-step in-situ growth to construct a MOF-74/MIL-53 heterojunction. On this basis, we used the localized surface plasmon resonance (LSPR) effect of gold nanoparticles (Au NPs) to significantly improve the oxygen evolution reaction performance of MOF-74/MIL-53 heterojunction. Under illumation, the obtained Au-MOF-74/MIL-53 exhibits a lower overpotential of 218 mV, which is far superior to commercial catalyst. The reaction kinetics are significantly enhanced due to the lower charge transfer resistance and the higher electric double layer capacitance. We confirmed the existence of charge transfer between Au NPs and MOFs, and at the same time, the deposition of Au NPs significantly reduced the charge transfer resistance of MOF-74/MIL-53. On the basis of our work, we provide a novel MOF-based electrocatalytic nanocomposite structure for efficient water splitting.

Graphene oxide based Gd2O3:Eu3+ nanocomposites: A multifaceted approach to advanced energy storage and bio sensing applications

This investigation delves into the synthesis and characterization of graphene oxide (GO) based gadolinium oxide europium-doped nanocomposites (GO-Gd2O3:Eu3+ (1 mol %) NCs), emphasizing their utility in super capacitors and biosensors. Utilizing a hydrothermal process with graphene oxide, the study enhances Gd2O3 energy storage capabilities, complemented by europium’s luminescent features for real-time monitoring. Structural, morphological, and chemical analyses by X-ray diffraction (XRD), Transmission electron microscopy (TEM), and electrochemical (CH) Analyzer, reveal promising electrochemical performance, reaching specific capacitance values of 512.14 Fg−1 in 1 M H2SO4 electrolyte. The electrodes exhibit commendable rate capability, cycling stability, and a Coulombic efficiency of 94.54 % after 5000 galvanostatic charge–discharge (GCD) cycles. Impedance spectroscopy confirms low charge transfer resistance, contributing to enhanced electrochemical performance. Moreover, the integration of europium imparts luminescent properties, positioning these super capacitors for integrated sensing applications. The luminescence allows real-time monitoring, showcasing the versatility of GO-Gd2O3:Eu3+ based NCs for future technologies, particularly in smart sensors, wearables, and integrated electronics.

Highly Selective Electroreduction of Nitrobenzene to Aniline by Co-Doped 1T-MoS2.

The selective electrocatalytic reduction of nitrobenzene (NB) to aniline demands a desirable cathodic catalyst to overcome the challenges of the competing hydrogen evolution reaction (HER), a higher overpotential, and a lower selectivity. Here, we deposit Co-doped 1T MoS2 on Ti mesh by the solvothermal method with different doping percentages of Co as x % Co-MoS2 (where x = 3, 5, 8, 10, and 12%). Because of the lowest overpotential, lower charge-transfer resistance, strong suppression of the competing HER, and higher electrochemical surface area, 8% Co-MoS2 achieves 94% selectivity of aniline with 54% faradaic efficiency. The reduction process follows first-order dynamics with a reaction coefficient of 0.5 h-1. Besides, 8% Co-MoS2 is highly stable and retains 81% selectivity even after 8 cycles. Mechanistic studies showed that the selective and exothermic adsorption of the nitro group at x % Co-MoS2 leads to a higher rate of NB reduction and higher selectivity of aniline. The aniline product is successfully removed from the solution by polymerization at FTO. This study signifies the impact of doping metal atoms in tuning the electronic arrangement of 1T-MoS2 for the facilitation of organic transformations.

Electro-assisted sorption behavior and mechanism of low-concentration rare earth elements on carbon based materials

With increasing demands for rare earth elements (REEs) in high-tech and futuristic applications, developing efficient methods for recovering low-concentration REEs is necessary. Here, electro-assisted sorption of low-concentration REEs, La(III), Gd(III) and Y(III) (as symbol of light, medium, and heavy REEs) on carbon-based materials, activated carbon (AC), graphene, and graphite by a facile method was reported. Recovery of La(III), Gd(III) and Y(III) could reach ∼100 % under low-concentration condition where the maximum adsorption capacity was up to 342.38 mg/(g·dm2). Variants including applied voltage, electrodes-distance, pH, impurities, and concentration were considered to study the effects on REEs recovery. Interestingly, adsorption capacity and recovery under low voltage were respectively almost 20 and 14 folds than that without voltage, because voltage promoted REEs transfer and strengthened electrostatic interaction between electrodes and REEs. The mechanism for enhancing REEs recovery on carbon-based electrodes was resulted from high electric double layer (EDL) capacitance and low charge transfer resistance. Total desorption of REEs from electrodes could be quickly realized using NH4Cl or HCl solution. Overall, the study gave a new insight of low-concentration REEs recovery using carbon-based materials, and provided an efficient route using electric method with porous materials for REEs recovery.

In situ electrodeposited Zn-doped CoNiS as an efficient and stable electrocatalyst for overall water splitting in neutral media

Zinc-doped cobalt nickel sulfides coupled with polypyrrole hollow nanospheres grown on carbon paper (Zn-CoNiS/PHS/CP) were developed by unipolar pulse electrodeposition (UPED) method as efficient and stable electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting in neutral media for the first time. With abundant active sites intrigued by moderate Zn doping, the optimized Zn10-CoNiS delivers improved catalytic performance with small overpotentials of 213 mV and 414 mV to achieve the current densities of 10 mA cm−2 for HER and OER respectively, and outstanding long-term stability. The water electrolyzer device with Zn10-CoNiS as both anode and cathode delivers a current density of 10 mA cm−2 at a cell voltage of 1.896 V in neutral media. The low charge transfer resistance of Zn-CoNiS and confinement effect of 2D Ni9S8/Co9S8 nanosheets on 0D ZnS nanodots endow the bifunctional electrocatalysts with efficient activity and high stability, providing a competitive candidate for green hydrogen production.

One-step synthesis of self-supporting porous Cu81(Ni,Co)19 intermetallic catalysts for hydrogen evolution reaction

The development of hydrogen evolution reaction (HER) catalysts with excellent performance is the key to the wide-scale application of hydrogen energy. Herein, this work facilely synthesizes the self-supporting porous Cu81(Ni,Co)19 electrocatalysts by dealloying ZrNiCoCuAl amorphous alloy in HF solution. By regulating the composition of ZrNiCoCuAl amorphous alloy dealloying precursor, the porous Cu81(Ni,Co)19 composite synthesized by dealloying Zr60Ni8Co8Cu16Al8 amorphous alloy demonstrates the great HER performance with an overpotential of 35 mV at 10 mA cm−2 and a Tafel slope of 73.3 mV dec−1. The outstanding catalytic performance of porous Cu81(Ni,Co)19 is attributed to the hierarchical porous structure, low charge transfer resistance as well as the synergistic interactions among the Cu, Ni and Co elements. Moreover, the theoretical calculations indicate that the constituent Cu, Co and Ni elements in the Cu81(Ni,Co)19 intermetallic alloy can act synergistically to optimize the free energy of hydrogen adsorption, therefore improve HER activity.

Controlling the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers via the design of condensed structures

Obtaining lignin-based graphite-like microcrystallites at a relatively low carbonization temperature is still very challenging. In this work, we report a new method based on condensed structures, for regulating graphite-like microcrystalline structures via the incorporation of 4,4′-diphenylmethane diisocyanate (MDI) into the main structure of lignin. The effects of MDI on the thermal properties of lignin and the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers were extensively studied and investigated. The incorporation of MDI decreased the thermal stability of lignin, increased the carbon yield and enhanced the formation of graphite-like microcrystallites, which are beneficial for reducing energy consumption during the preparation of lignin-based carbon fibers. The modified lignin-based ultrafine carbon fibers (M-LCFs) demonstrated satisfactory electrochemical performance, including high specific capacitance, low charge transfer resistance, and good cycle performance. The M-LCFs-3/2 electrode had a specific capacitance of 241.3 F g−1 at a current density of 0.5 A g−1, and a residual ratio of 90.2 % after 2000 charge and discharge cycles. This study provides a new approach to control the graphite-like microcrystalline structure and electrochemical performance while also optimizing the temperature.

CuO/CeAlO3 nanocomposite with enhanced electrocapacitive performance for supercapacitor applications

Developing an efficient system is essential for energy storage, especially sustainable sources of energy, which have expanded significantly in the last few years. However, the fabrication of effective materials proves an aid to solve such crises of high cost and low specific capacitance. Transition and inner transition metal oxides play a significant role in energy storage as well as energy conversion systems. In this research, a novel material CuO/CeAlO3 nanocomposite is synthesized by sonication technique for supercapacitor applications. The different physical methods including X-ray diffractometer (XRD), Raman and Scanning Electron Microscopy (SEM) were employed to analyze the phase purity, structure as well as morphology of the prepared electrode. Electrochemical investigations concluded that the CuO/CeAlO3 nanocomposite exhibited specific capacitance of 1091.98 F/g, high energy density of 56.26 Wh/kg, high power density of 304.55 W/kg at 1 A/g current density as well as high cyclic stability after 5000th cycle with lower charge transfer resistance of 0.09 Ω. The electrochemical characteristics of CuO/CeAlO3 nanocomposite were improved because of the increased area of surface, large active sites and decreased resistance that resulted from the addition of CeAlO3 with CuO. This research showed the great potential of CuO/CeAlO3 nanocomposite along with inexpensive fabrication cost and could be used in next-generation energy storage systems.

Asymmetric reactors as an innovative approach for optimum microbial fuel cells performance

Microbial fuel cells (MFCs) exhibit asymmetric overpotentials and redox potentials/rates at the cathode and anode. However, the impact of this asymmetric on power density and anode microbial community remains poorly understood. In this study, asymmetric reactors were designed for H-type MFCs to investigate this configuration. Contrary to the initial expectation of increased MFC power output with larger cathode volumes, it was unexpectedly found that the small-cathode reactor outperformed the large-cathode reactor, achieving a 61 % increase in maximum power density. Electrochemical characterization revealed a slightly lower charge transfer resistance (29.34 Ω) in the small-cathode reactor with carbon-felt anode biofilm in PBS. Moreover, 16S rRNA sequence analysis showed that the small-cathode reactor harbored a higher proportion of anaerobic bacteria (83 %), lower species diversity, and a higher abundance of exoelectrogens. Additionally, higher abundances of key gene modules (top eight), such as quinone oxidoreductase and citrate cycle, were observed in the small-cathode reactor. The anode biofilms in both reactors also synthesized some vitamins, such as menaquinone and thiamine. Furthermore, compared to the large-cathode reactor, each set of the small-cathode reactor saved ¥ 20, 23 g of borosilicate, and 55 mL of cathode electrolytes. This study sheds light on the interplay between reactor conformation and performance, contributing to the development of low-cost, high-performance MFCs for real field conditions.