Electron Transfer Ability Research Articles

Advances in electrochemically active biofilm of Shewanella oneidensis MR-1

Facing the increasingly severe energy shortage and environmental pollution, electrocatalytic processes using electroactive microorganisms provide a new alternative for achieving environmental-friendly production. Because of its unique respiratory mode and electron transfer ability, Shewanella oneidensis MR-1 has been widely used in the fields of microbial fuel cell, bioelectrosynthesis of value-added chemicals, metal waste treatment and environmental remediation system. The electrochemically active biofilm of S. oneidensis MR-1 is an excellent carrier for transferring the electrons of the electroactive microorganisms. The formation of electrochemically active biofilm is a dynamic and complex process, which is affected by many factors, such as electrode materials, culture conditions, strains and their metabolism. The electrochemically active biofilm plays a very important role in enhancing bacterial environmental stress resistance, improving nutrient uptake and electron transfer efficiency. This paper reviewed the formation process, influencing factors and applications of S. oneidensis MR-1 biofilm in bio-energy, bioremediation and biosensing, with the aim to facilitate and expand its further application.

Non-enzymatic electrochemical malathion sensor based on bimetallic Cu-Co metal-organic gels modified glassy carbon electrode

A non-enzymatic electrochemical sensor based on bimetallic Cu-Co metal-organic gel (MOG) modified glassy carbon electrode (GCE) was reported to achieve super-sensitive malathion detection. Phytic acid-based Cu-Co bimetallic MOG (PA-Cu-Co composite) is a kind of three-dimensional porous material and has a large surface area and superior conductivity due to crosslinked network structure and bimetal composition. The obtained PA-Cu-Co/GCE sensor can easily bond malathion due to the good affinity between Cu element and sulfur groups of malathion, leading to an inhibited redox signal of Cu element in presence of malathion. The electrode reaction was a typical adsorption controlled process. The introduction of Co element not only greatly improves the electron transfer ability but increases surface area and active sites of sensor interface for high affinity of malathion, thus endowing PA-Cu-Co composite with outstanding sensitivity and selectivity. Under optimized operating conditions, the enzyme-free PA-Cu-Co/GCE malathion sensor exhibits good stability and excellent detection performance, with a wide linear range to malathion of 0.5 pM to 5 μM and low detection limit of 0.3 pM. Furthermore, the PA-Cu-Co/GCE sensor showed good recovery in real samples detection, implicating the potential applicability of PA-Cu-Co/GCE sensor in sensitive and selective detection of organophosphorus pesticides (OPs).

Cynodon dactylon derived fluorescent N-doped carbon dots: Implications of photocatalytic and biological applications

CQDs possess various appealing properties like excellent light harvesting capability, unique photo-induced electron transfer ability, low toxicity, and good biocompatibility. This work aims to demonstrate the potential of CQDs from natural waste resources in wastewater treatments and biomedical applications. Herein we report the eco-friendly approach for preparing nitrogen-doped carbon quantum dots (N-CQDs) using the Cynodon dactylon (grass) as a carbon precursor via a highly effective hydrothermal process. The structural aspects and chemical nature of N-CQDs were considered using FTIR, XRD, SEM & EDX, TEM, AFM, EPR, and XPS. In addition, UV–vis and fluorescence spectroscopy elucidated the optical performance of N-CQDs. N-CQDs possess stable fluorescent properties, good biocompatibility, and acceptable quantum yield (24.44%). In this study, five dyes, namely Toluidine Blue (TB), Amido Black (AB), Congo Red (CR), and Xylol Orange (XO), were chosen to investigate the photocatalytic performance of the nanomaterial under UV–vis light irradiation. The synthesized N-CQDs exhibited remarkable photocatalytic activity for various model dyes of varying concentrations (5, 10, 50, and 100 ppm), highlighting the pivotal role of N-CQDs in promoting the separation migration efficiency of photoexcited e−- h+ pairs. Moreover, the impact of pH, contact time, and amount of catalyst on the degradation of dyes were also examined. Additionally, we investigated the interaction of N-CQDs with lysozyme protein using fluorescence quenching. Thus, the developed nanomaterial efficiently treats wastewater and holds great promise in biosensing applications.

Tuning octahedron sites in MnFe2O4 spinel by boron doping for highly efficient seawater splitting

Seawater splitting requires highly active and stable electrocatalysts to sustain electrolysis without chloride corrosion, especially for the anode. Herein, a boron (B) doped MnFe2O4 spinel-type electrocatalyst with a heterostructure was derived from MnFe-MOF-74 precursor and applied for seawater electrolysis. It is found that the introduction of B species can effectively optimize the electronic configuration of MnFe2O4 with the promoted electron transfer ability between neighboring O to FeOh, thereby significantly reducing the energy barrier of the electron transfer and boosting the reaction process. As expected, in the real seawater environment, it required a low overpotential of 330 mV for oxygen evolution reaction (OER) to drive a current density of 100 mA cm−2 at 60 ℃, and exhibited high stability for over 200-h continuing test without producing hypochlorite and corrosion. This work provides a new strategy for enhancing the intrinsic activity of spinel-type oxides in seawater splitting.

Enhancement of chromium (VI) removal and power generation by adding biochar to a single-medium sediment-based microbial fuel cell

A single-medium membrane-less sediment microbial fuel cell (SMFC) was developed to remove Cr6+ from sediment by embedding its cathode and anode in the sediment, so that the electrons that are generated by the degradation of organic matter at the anode are received by Cr6+ at the cathode, reducing the competition for oxygen. The best power density and Cr6+ removal efficiency of the SMFC were found to be 8.8 mW/m3 and 60.9 %, respectively, for a system in a high Cr6+ concentration (600 mg/kg). Biochar has a high specific surface area and adsorption capacity, facilitating electron transfer. As an electron mediator, peanut husk biochar that was sintered at 800 °C had an electron transfer capacity of 0.295 mmol e−/g biochar. This biochar was added to the SMFC system to improve its performance by exploiting the electron transfer ability of the biochar, increasing the electricity production and Cr6+ removal efficiency of the SMFC. The power density and Cr6+ removal efficiency of the biochar-added system were 55.1 mW/m3 and 97.74 %, or 6.26 times and 1.6 times those of the system without biochar, respectively, indicating the improvement that is provided by adding biochar.

Sub-inhibitory concentrations of ampicillin affect microbial Fe(III) oxide reduction

Antibiotics are ubiquitous in the iron-rich environments but their roles in microbial reduction of Fe(III) oxides are still unclear. Using ampicillin and Geobacter soli, this study investigated the underlying mechanism by which antibiotic regulated microbial reduction of Fe(III) oxides. Results showed that sub-minimal inhibitory concentrations (sub-MIC) of ampicillin significantly affected ferrihydrite reduction by G. soli, with a stimulatory effect at 1/64 and 1/32 MIC and an inhibitory effect at 1/8 MIC. Increasing ampicillin concentration resulted in increasing cell length and decreasing bacterial zeta potential that were beneficial for ferrihydrite reduction, and decreasing outer membrane permeability that was unfavorable for ferrihydrite reduction. The respiratory metabolism ability was enhanced by 1/64 and 1/32 MIC ampicillin and reduced by 1/8 MIC ampicillin, which was also responsible for regulation of ferrihydrite reduction by ampicillin. The ferrihydrite reduction showed a positive correlation with the redox activity of extracellular polymeric substances (EPS) which was tied to the cytochrome/polysaccharide ratio and the content of α-helices and β-sheet in EPS. These results suggested that ampicillin regulated microbial Fe(III) oxide reduction through modulating the bacterial morphology, metabolism activity and extracellular electron transfer ability. Our findings provide new insights into the environmental factors regulating biogeochemical cycling of iron.

Review of Emission Characteristics and Purification Methods of Volatile Organic Compounds (VOCs) in Cooking Oil Fume

Volatile organic compounds (VOCs) in cooking oil fumes need to be efficiently removed due to the significant damage they cause to the environment and human health. This review discusses the emission characteristics, which are influenced by different cooking temperatures, cooking oils, and cuisines. Then, various cooking oil fume purification methods are mainly classified into physical capture, chemical decomposition, and combination methods. VOCs removal rate, system operability, secondary pollution, application area, and cost are compared. The catalytic combustion method was found to have the advantages of high VOC removal efficiency, environmental protection, and low cost. Therefore, the last part of this review focuses on the research progress of the catalytic combustion method and summarizes its mechanisms and catalysts. The Marse-van Krevelen (MVK), Langmuir-Hinshelwood (L-H), and Eley-Rideal (E-R) mechanisms are analyzed. Noble metal and non-noble metal catalysts are commonly used. The former showed excellent activity at low temperatures due to its strong adsorption and electron transfer abilities, but the high price limits its application. The transition metals primarily comprise the latter, including single metal and composite metal catalysts. Compared to single metal catalysts, the interaction between metals in composite metal catalysts can further enhance the catalytic performance.

Green synthesis of cyclodextrin-capped AuNPs decorated on polystyrene microspheres for a furazolidone-responsive electrode

Herein, a glassy carbon electrode modified with polystyrene microspheres decorated with β-cyclodextrin-capped gold nanoparticles (denoted P/CD@AuNPs/GCE) was designed to scrutinize the electrochemical sensing behavior of furazolidone (FZ) for the first time. Various spectroscopic and microscopic techniques were applied to characterize the physiochemical attributes of the prepared P/CD@AuNPs. Compared to bare GCE, P/CD@AuNPs/GCE unveils higher peak currents with lower peak potentials. Due to the presence of a combination of monodispersed CD@AuNPs on the PS surface, it benefits from high electrical conductivity, ghost-guest interaction, and rapid electron transfer ability, thus warranting competent electrocatalytic performance. The sensor showed great sensitivity, wide linear range (0.05–715 μM), low limit of detection (2.03 nM), superior selectivity, good repeatability, and reproducibility (1.29%) toward FZ detection. The sensor was successfully validated on a real human blood serum sample, and excellent recovery values (90%−101.2%) were achieved. The devised sensor offers a competent and promising sustainable electrocatalyst for monitoring FZ in human blood serum.

Tailoring alloy compositions by glucose towards superior Ni–Cu–C electrocatalysts for hydrogen evolution reaction

Developing efficient, economic, and environment-friendly electrocatalysts to meet the industrialized hydrogen evolution reaction (HER) needs is highly desired for dealing with the energy crisis. Under the known premise, how to reasonably control the doping amount of copper greatly influences the structure and is one of the key factors affecting the performance of the catalyst. Herein, a series of Ni–Cu–C electrocatalysts are successfully synthesized through a simple electrodeposition method. The unique dendritic morphology can be obtained by adjusting the different glucose concentrations. DFT simulation reveals that the proper proportion of copper can significantly modulate the H adsorption-free energy ΔGH∗ It can boost the intrinsic activity of Ni–Cu–C catalysts. NCC-3 delivers an overpotential of 87 mV and 165 mV in alkaline media at the current density of 10 mA cm−2 and 100 mA cm−2, respectively and presents outstanding long-term stability for 50 h. Such excellent HER activity stems from a large ECSA area and better electron-transfer ability. The study presents a feasible way to control metal alloy catalysts' composition in the electrodeposition process.

Electrochemical Dechlorination of Trichloroethylene by Manganese Phthalocyanine: Performance and Mechanisms

Trichloroethylene (TCE) is one of the most abundant persistent organic pollutant in subsurface environment. TCE can be reduced electrochemically, but the extremely negative applied potential limits the application of this technology. Manganese phthalocyanine (MnPc) catalyst was used for the electrochemical reductive dechlorination of TCE. The results show that MnPc can be reduced by electrons attachment at −-0.21 V, −-1.22 V and −-1.77 V, respectively. With the decrease of applied potential from −-0.3 V to −-1.8 V, the transformation from TCE to dichloroethylene (DCE) efficiency increased from 19.9% to 41.8% after 5 hours of reaction. Although the electron transfer ability was enhanced with applied potential decreasing, the intensive HER caused the electron selectivity decreased when MnPc attached more electrons. MnPc catalyze the electrochemical reduction of TCE, which has potential application on the remediation of TCE-contaminated groundwater.

Fabrication of a Novel CNT-COO-/Ag3PO4@AgIO4Composite with Enhanced Photocatalytic Activity under Natural Sunlight.

In this study, a carboxylated carbon nanotube-grafted Ag3PO4@AgIO4 (CNT-COO-/Ag3PO4@AgIO4) composite was synthesized through an in situ electrostatic deposition method. The synthesized composite was characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and energy-dispersive X-ray spectroscopy (EDS). The electron transfer ability of the synthesized composite was studied using electrochemical impedance spectroscopy (EIS). The CNT-COO-/Ag3PO4@AgIO4 composite exhibited higher activity than CNT/Ag3PO4@AgIO4, Ag3PO4@AgIO4, and bare Ag3PO4. The material characterization and the detailed study of the various parameters thataffect the photocatalytic reaction revealed that the enhanced catalytic activity is related to the good interfacial interaction between CNT-COO and Ag3PO4. The energy band structure analysis is further considered as a reason for multi-electron reaction enhancement. The results and discussion in this study provide important information for the use of the functionalized CNT-COOH in the field of photocatalysis. Moreover, providinga new way to functionalize CNT viadifferent functional groups may lead to further development in the field of photocatalysis. This work could provide a new way to use natural sunlight to facilitate the practical application of photocatalysts toenvironmental issues.

Electron Transfer of Activated Carbon to Anode Excites and Regulates Desalination in Flow Electrode Capacitive Deionization.

The desalination performance of flow electrode capacitive deionization (FCDI) is determined by the ion adsorption on the powdered activated carbon (PAC) and the electron transfer between the current collector and PAC. However, a comprehensive understanding of rate-limiting steps is lacking, let alone to enhance FCDI desalination by regulating the PAC characteristics. This study showed that the electron transfer between PAC and the current collector on the anode side was the rate-limiting step of FCDI desalination. Compared with W900, the desalination performance of FCDI decreased by 95% when W1200 with weak electron transfer ability was used as a flow electrode. The PAC selected in this study transferred electrons directly through the conductive carbon matrix in FCDI and was mainly affected by graphitization. The desalination performance of FCDI was improved by 20 times when the graphitization degree of PAC increased from 0.69 to 1.03. The minimum energy required for electrons to escape from the PAC surface was reduced by the high degree of graphitization, from 4.27 to 3.52 eV, thus improving the electron transfer capacity of PAC on the anode side. This study provides a direction for the optimization of flow electrodes and further promotes the development of FCDI.

A facile aqueous-phase synthesis of Co-based nanostructures composed of cobalt hydroxide and cobalt oxide for enhanced photocatalytic activity of dye-sensitized H2 production

Transition metal catalysts are more cost competitive than noble metal catalysts, but there is a drawback in that catalyst activity must be greatly increased for industrial use. In this research, we report the formation of cobalt-based mixture nanostructures composed of cobalt hydroxide having high photoelectron attracting force, electron transfer ability, and easy access and cobalt oxide having facile charge transfer based on the interchangeability to significantly increase the activity of transition metal-based catalysts. Furthermore, the Co-based nanostructures (CNS) were easily synthesized via an aqueous-phase synthesis, and the molar ratio of α-Co(OH)2/Co3O4 was controlled by simply varying the reaction time. Due to the well-mixed structure of α-Co(OH)2 and Co3O4, which could have a beneficial effect on each other in a photocatalytic reaction, the CNS exhibited 11 times superior hydrogen production than the commercial α-Co(OH)2 in a photocatalytic hydrogen production reaction.

Photocatalytically Active Semiconductor Cu3P Unites with Flocculent TiN for Efficient Removal of Sulfamethoxazole

Sulfamethoxazole is a widely—used antibiotic with high water solubility and low biodegradability, which was considered a refractory environmental pollutant. Hence, a series of functionalized hybrids uniting Cu3P with TiN were prepared. The Cu3P/TiN—x composites remarkably removed the sulfamethoxazole in solution compared with Cu3P and TiN alone. All the as—prepared Cu3P/TiN—x hybrids integrated the advantages of strong adsorption and photocatalysis and achieved removal rates above 70% of sulfamethoxazole. Among the composites, the Cu3P/TiN—2 with a 1:1 molar ratio of Cu: Ti reached a 90% removal rate under dark adsorption for 30 min and subsequent photodegradation for 120 min. The enhanced performance of the Cu3P/TiN—x composites is attributed to the introduced flocculent TiN with a large specific surface area and high conductivity that provide more reactive sites and high electron transferability. Meanwhile, the strong corrosion resistance and chemical stability were also beneficial to the improved performance. Cycling experiments further demonstrate the stability and reliability of the composites. In addition, the capture experiments indicated that the superoxide radical (·O2−) and hydroxyl radical (·OH) played a major role in sulfamethoxazole degradation.

Peracetic acid activation via the synergic effect of Co and Fe in CoFe-LDH for efficient degradation of pharmaceuticals in hospital wastewater

As an oxidant, peracetic acid (PAA) is gradually applied in advanced oxidation processes (AOPs) for pollutants degradation due to its high oxidation and low toxicity. In this study, the prepared Co2Fe1-LDH showed excellent PAA activation ability for efficient degradation of various pharmaceuticals with a removal efficiency ranging from 82.3% to 100%. Taking sulfamethoxazole (SMX) as a model pharmaceutical, it's found that organic radical (R-O•) with high concentration of 5.27 × 10−13 M is the dominant ROS responsible for contaminants degradation. Further analysis demonstrated that bimetallic synergistic effect between Co and Fe can improve electron transfer ability of Co2Fe1-LDH, resulting in the accelerated conversion of Co from +3 to +2 valence state with a high reaction rate (4.3 × 101–1.483 × 102 M−1 s−1) in this system. Density functional theory (DFT) reveals that C1, C3, C5 and N11 with higher ƒ0 and ƒ−values concentrated on aniline group of SMX are the main attack sites, which is consistent with the results of degradation products. Besides, Co2Fe1-LDH/PAA system can effectively reduce biological toxicity after reaction, due to lower biotoxicity of degradation products and the carbon sources provided by PAA. In application, Co2Fe1-LDH/PAA system was capable of resisting the influence of water matrix and effectively removing pollutants in actual hospital wastewater. Importantly, this study comprehensively evaluated the ability of Co2Fe1-LDH/PAA system to remove organics and improve the biodegradability of actual hospital wastewater, providing guidance for application of PAA activation system.

Facet-Dependent Catalytic Activity of MnFe Prussian Blue Analogues in Peroxymonosulfate-Activated System for Efficient Degradation of Acetamiprid

MnFe Prussian blue analogues (MnFe PBAs) were fabricated for acetamiprid degradation with peroxymonosulfate (PMS) as an oxidant. MnFe PBAs (200) are the most active facets for PMS activation due to the superior chemisorption affinity and electron-transfer ability. Density functional theory calculation verified that Mn(III) served as an electron donor and acceptor to adjust the electron density between Fe and Mn, which played a crucial role in the high activation performance of MnFe PBAs (200). PBA lattice (−C═N) did not exhibit direct PMS activation capability in this system, which differed from previously reported Fenton counterparts. Based on the electronic localization function calculation and probe experiments, the O–O of HSO5– was broken, and the bonds of PBA could be restored during the activation reaction, leading to the continuous generation of reactive oxygen species in the MnFe PBAs/PMS system. Transformation product studies indicated that the oxidized products were primarily the result of aromatic hydroxylation, N–C bond cleavage, azo reaction, and so forth, achieving the mineralization and ecotoxicity mitigation of acetamiprid efficiently. Findings in this study provided new insights into developing advanced facet-dependent catalysts to activate PMS for the efficient degradation of emerging contaminants in the aqueous environment.

Synthesis and water splitting performance of FeCoNbS bifunctional electrocatalyst

Transition metal (TM) sulfides are promising catalysts for water splitting in alkaline media due to their high intrinsic activities and similar TM-S electronic structure with hydrogenase. In this work, the nanoporous FeCoNbS electrocatalyst with nanosheet morphology is synthesized through dealloying AlFeCoNb alloy followed by the steam sulphurization. The introduction of S element improves the electronic structure, further increases the active sites, regulates the mass transfer and enhances the intrinsic activity. The Nb introduction improves the electron transfer ability of the catalyst. The synergistic effect of Fe, Co and Nb improves the intrinsic activity of the active site. The FeCoNbS catalyst exhibits good catalytic performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution. The overpotentials at 10 mA cm−2 of HER and OER are 83 and 241 mV, respectively. The Tafel slopes of HER and OER are 101.2 and 35.5 mV dec−1, respectively. The FeCoNbS can serve as overall water splitting electrode with the decomposition voltage of 1.61 V at 10 mA cm−2.

Nanofibrillar biochar from industrial waste as hosting network for transition metal dichalcogenides. Novel sustainable 1D/2D nanocomposites for electrochemical sensing

Industrial wastes have become elective sustainable sources to obtain materials for electronic/electroanalytical purposes; on the other hand, easy and green strategies to include semiconductor 2D graphene-like materials in conductive networks are highly required.In this work, 1D/2D nanocomposites (NCs) based on nanofibrillar biochar (BH) from paper industry waste and transition metal dichalcogenides (TMDs: MoS2, WS2, MoSe2, and WSe2), were prepared in water via liquid phase exfoliation (LPE) using sodium cholate as bioderived surfactant. The TMD amount in the NCs has been carefully optimized, searching for the best compromise between electron transfer ability and electroanalytical performances. Four different water-dispersed BH-TMD NCs have been selected and comprehensively studied from the electrochemical point of view and morphologically characterized. The BH-TMDs potentiality have been demonstrated in model solutions and real samples towards different analytes of biological and agri-food interest. The most performing NCs have been selected and used for the simultaneous determination of the neurotransmitters dopamine (DP) and serotonin (SR), and the flavonoids quercetin (QR) and rutin (RT), obtaining good linearity (R2 ≥ 0.9956) with limits of detection ranging from 10 to 200 nM. Reproducible quantitative recovery values (90–112%, RSD ≤6%, n = 3) were obtained analyzing simultaneously DP and SR in synthetic biological fluid and drugs, and QR and RT in food supplements, proving the usability of the proposed materials for real analyses.This work proves that BH-nanofibers act as a sustainable conductive hosting network for 2D-TMDs, allowing full exploit their electroanalytical potential. The proposed BH-TMD NCs represent a sustainable, affordable, and captivating opportunity for the electrochemical and (bio)sensoristic field.

A novel BC/g-C3N4 porous hydrogel carrier used in intimately coupled photocatalysis and biodegradation system for efficient removal of tetracycline hydrochloride in water

Intimately coupled photocatalysis and biodegradation (ICPB) is a promising technology to remove refractory contaminants from water. The key to successful ICPB is a carrier capable of accumulating biofilm and adhering photocatalyst firmly. Herein, BC/g-C3N4 was prepared into a three dimensional porous hydrogel and used as a carrier in ICPB system for the first time. Degradation experiments revealed that the removal rate of tetracycline hydrochloride (TCH) in water by the ICPB system was 96.0% after 10 h, which was significantly higher than that by the photocatalysis (PC, 76.3%), biodegradation (B, 32.5%), adsorption (AD, 17.2%), and photolysis (P, 5.0%) systems. Photo-electrochemical tests confirmed that ICPB system had superior electron transfer ability between photocatalysts and microorganisms. The removal efficiency of COD proved that microorganisms played an important role in the mineralization process of TCH by the ICPB system. After the ICPB degradation experiment, microorganisms maintained high activity and Pseudomonas, Burkholderiaceae and Flavobacterium which had TCH degradation or electron transport ability, were enriched. In conclusion, the novel ICPB carrier overcame shortcomings of the traditional ICPB carrier and the novel ICPB system had superior degradation performance for TCH. This study provided a possible method to promote the practical application of ICPB technology.

Light Field-Enhanced Single-Site Cu Electrocatalyst for Nitrogen Fixation.

Direct electrocatalytic reduction of N2 to NH3 under mild conditions is attracting considerable interests but still remains enormous challenges in terms of respect of intrinsic catalytic activity and limited electrocatalytic efficiency. Herein, a photo-enhanced strategy is developed to improve the NRR activity on Cu single atoms catalysts. The atomically dispersed Cu single atoms supported TiO2 nanosheets (Cu SAs/TiO2 ) achieve a Faradaic Efficiency (12.88%) and NH3 yield rate (6.26µg h-1 mgcat -1 ) at -0.05V versus RHE under the light irradiation field, in which NH3 yield rate is fivefold higher than that under pure electrocatalytic nitrogen reduction reaction (NRR) process and is remarkably superior in comparison to most of the similar type electrocatalysts. The existence of external light field improves electron transfer ability between CuO and TiO, and thus optimizes the accumulation of surface charges on Cu sites, endowing more electrons involved in nitrogen fixation. This work reveals an atomic-scale mechanistic understanding of field effect-enhanced electrochemical performance of catalysts and it provides predictive guidelines for the rational design of photo-enhanced electrochemical N2 reduction catalysts.