Reduction Pathway Research Articles

Unveiling the Roles of Lattice Strain by Ni Exsolution on Photothermal Reduction of CO2 Activity in BaTiO3 Catalyst.

The lattice strain influences crystal orientation, facets exposed to external light, and atom rearrangement strongly to affect catalytic activity. However, how to rationally design a metal-oxide heterojunction catalyst with featuring lattice strain is a great challenge. Herein, a facile method is adopted to induce lattice strain upon in situ exsolution of Ni nanoparticles from Ba0.9Ti0.9Ni0.1O3-δ (BTNO) perovskite oxide, hereby enhancing the photothermal reduction of CO2. Lattice strain and Ni-exsolution dual regulation ensure that the Ni-anchored BTNO catalyst displays superb photothermal reduction activity of CO2. It shows a CO yield of 40.50 mmol gcat -1 h-1 and a CH4 yield of 19.62 mmol gcat -1 h-1, which are 14 and 73 times higher than those of BaTiO3. In addition, in situ DRIFTS and density functional theory (DFT) calculations reveal the CO2 reduction pathways and strain modulates the interfacial band structure and enhances the transfer of photogenerated charge. Consequently, this study provides a new approach for achieving highly efficient photothermal catalytic reduction of CO2 through strain engineering.

Core cooperative metabolism in low-complexity CO2-fixing anaerobic microbiota.

Biological conversion of carbon dioxide into methane has a crucial role in global carbon cycling and is operated by a specialised set of anaerobic archaea. Although it is known that this conversion is strictly linked with cooperative bacterial activity, such as through syntrophic acetate oxidation, there is also a limited understanding on how this cooperation is regulated and metabolically realised. In this work, we investigate the activity in a microbial community evolved to efficiently convert carbon dioxide into methane and predominantly populated by Methanothermobacter wolfeii. Through multi-omics, biochemical analysis and constraint-based modelling, we identify a potential formate cross-feeding from an uncharacterised Limnochordia species to M. wolfeii, driven by the recently discovered reductive glycine pathway and upregulated when hydrogen and carbon dioxide are limited. The quantitative consistency of this metabolic exchange with experimental data is shown by metagenome-scale metabolic models integrating condition-specific metatranscriptomics, which also indicate a broader three-way interaction involving M. wolfeii, the Limnochordia species, and Sphaerobacter thermophilus. Under limited hydrogen and carbon dioxide, aspartate released by M. wolfeii is fermented by S. thermophilus into acetate, which in turn is convertible into formate by Limnochordia, possibly forming a cooperative loop sustaining hydrogenotrophic methanogenesis. These findings expand our knowledge on the modes of carbon dioxide reduction into methane within natural microbial communities and provide an example of cooperative plasticity surrounding this process.

Selective nitric oxide redistribution by phospholipid nanoparticles: A novel strategy to mitigate massive nitric oxide release and prevent reperfusion injury in septic shock.

Nitric oxide plays a critical role in regulating vascular tone, but excessive nitric oxide release during septic shock results in hypotension due to excessive vasodilation and the formation of toxic free radicals. VBI-S is a phospholipid nanoparticle based fluid composed of lipid bilayers formed primarily by phosphatidylcholine and micelles of soybean oil encapsulated by a monolayer of phosphatidylcholine. These nanoparticles offer a novel solution by absorbing and redistributing nitric oxide and nitrite, potentially mitigating the harmful effects of excessive nitric oxide in sepsis. This paper proposes a mechanism in which VBI-S not only redistributes nitric oxide but also reduces ischemia-reperfusion injury by limiting the production and availability of reactive species. VBI-S captures nitric oxide and nitrite in areas of high concentration and redistributes them in low-nitric oxide environments, primarily within oxygen-deprived tissues. Nitrite then contributes to nitric oxide regeneration in hypoxic microvasculature via various reduction pathways, thereby improving tissue perfusion and minimizing oxidative stress. Preliminary studies suggest that nitrite may also decrease reactive species production, primarily superoxide, through the inhibition of mitochondrial complex I. Additionally, the lipid composition of VBI-S is rich in poly and monounsaturated fatty acids which allows VBI-S to act as a substrate for peroxidation via peroxynitrite. Therefore, VBI-S acts as a decoy target thereby protecting cellular membranes from oxidative damage caused by reactive species. These findings position VBI-S as a promising therapeutic agent, offering both nitric oxide regulation and protection against hypotension and toxic free radicals in septic shock patients. Further research is necessary to fully elucidate the molecular pathways and optimize its clinical application.

Key reaction pathways for NO reduction by NH3 in the reduction zone during ammonia-coal co-firing: A combined experimental and DFT study

Key reaction pathways for NO reduction by NH3 in the reduction zone during ammonia-coal co-firing: A combined experimental and DFT study

Centrality of Phosphate Binding Modes on Metal Vanadate in Exploiting Low-Temperature NOX Reduction and Pyrosulfate Dissociation Pathways

PO43- guests anchored on metal vanadate hosts are as vital as SO32-/SO42- analogues in wide exploitation for expediting acidic/redox SCR cycles or ABS pyrolysis at low temperatures. This is due to their multiple roles as a provider of Brönsted acidic bonds (BA--H+) and as a dictator of the traits for labile/mobile oxygens (OL/OM) and oxygen vacancies (OV). However, the relationships of BA- (P5+-O2-)/BA--H+ (P5+-O2--H+)/OL/OV/OM feature for the host versus its mono-/bi-dentate PO43- binding mode (PO43-MONO/PO43-BI) has never been examined to-date. PO43- guests were thus grafted on MnV2O6 host at 300 °C and 400-500 °C to generate PO43-MONO-abundant P300 and PO43-BI-bountiful P400-P500, respectively. PO43-MONO species elevated OV hydrophobicity and OM mobility for P300, which were pivotal to enhance its H2O resistance and redox cycle efficiency over P400-P500, respectively. Conversely, PO43-BI species outperformed PO43-MONO counterparts in achieving higher OL nucleophilicity, which was central to reduce the SCR energy barriers and to promote acidic cycle efficiencies for P400-P500. Moreover, P500 had such hydrophobic BA- species that reveal the lowest energy barrier for pyrosulfate (S2O72- of dehydrated ABS) fragmentation among P300-500, thereby unveiling higher ABS resistance than P300-P400 and bi-dentate SO32-/SO42--ample MnV2O6 control with humid, poisonous gases being fed.

Fast optimization of the emission reduction pathways of major air pollutants in China: From the perspective of different decision preferences.

To address the concern of optimization problem of China's PM2.5 control and the limitation of computational efficiencies for traditional air quality models, we developed an integrated analysis framework to efficiently establish the identification and cost-benefit assessment of PM2.5 control pathways in China by constructing a rapid PM2.5 exposure response method based on the high-order decoupled direct method (HDDM) and coupling the sequential least square algorithm (SLSQP) and health impact assessment model. Six emission reduction scenarios with varying decision preferences were analyzed. Our study provides a methodological approach for the rapid optimization of emission pathways of major air pollutants in China with flexible options in terms of objectives and constraints, fully considering the diverse differences in environmental, health, and economic impacts among different pollution sources simultaneously. Our findings based on the multi-scenario analysis strengthen the understanding of the importance of diverse species and regions for emission reduction among various decision preferences in China, confirm the necessity of implementing differentiated control strategies for distinct pollution sources from both cost and cost-effectiveness perspectives, and indicate that accelerating PM2.5 control process in the early stage is a beneficial choice for achieving more health benefits.

Bacterial community composition and metabolic characteristics of three representative Marine areas in northern China

Bacteria are essential components of ecosystems, participating in nutrient cycling and biogeochemical processes, and playing a crucial role in maintaining the stability of marine ecosystems. However, the biogeographic distribution patterns of bacterial diversity and metabolic functions in the estuarine and coastal areas of northern China remain unclear. Here, we used metagenomic sequencing to investigate the bacterial community composition and metabolic functions in sediments from the adjacent waters of the Yellow River Estuary, the Yellow Sea Cold Water Mass, and the adjacent waters of the Yangtze River Estuary. Among the 9164 species that were found, the most dominant microbial communities are Pseudomonadota, Actinomycetota, Bacteroidota, and Bacillota, but there are significant differences in the species composition in these three typical habitats. Amino acid metabolism and carbohydrate metabolic pathways were highly enriched. Glycoside hydrolases (GHs) predominate in carbon metabolism across all samples. In nitrogen metabolic pathway, genes related to organic degradation and synthesis are more abundant in the Yellow River Estuary than the other two habitats. In sulfur metabolic pathway, genes involved in assimilatory sulfate reduction are significantly enriched. Assimilatory sulfate reduction might be crucial for sulfur metabolism in coastal regions, with a full assimilatory nitrate reduction pathway found in Desulfobacterota. This research offers insights into the compositional diversity, metabolic functions, and biogeographic distribution patterns of bacterial communities in sediments from typical marine areas of northern China.

Saline water concentration determines the reduction pathway for oat phosphorus absorption

Saline water concentration determines the reduction pathway for oat phosphorus absorption

Membrane-covered aerobic composting mitigated nitrous oxide emission through improved micro-aerobic state and enhanced carbon source utilization.

In this study, the variables related to nitrous oxide (N2O) emissions and their interactions during membrane-covered aerobic composting (MCAC) and conventional aerobic composting were characterized at multiple scales. For the first time, it was quantified that the MCAC-created micro-positive pressure (50-500Pa) significantly increased compost particles aerobic layer thickness by 24%-27% (P<0.001). Pile-scale results demonstrated that MCAC decreased the abundance of key functional genes (nirS, nirK, cnorB, and nosZ) and microbes (norank_f__A4b, Halomonas, norank_f__norank_o__SBR1031, and norank_f__Xanthomonadaceae) associated with N2O emissions (P<0.001); MCAC significantly enhanced the microbial metabolic potential for carbohydrate-based, carboxylic acid-based, amino acid-based, lipid-based, organic phosphate-based, and amine-based carbon sources (P<0.05). Interaction analysis suggested that the improved micro-aerobic state inhibited the N2O generation pathway, while the increased microbial utilization of carbon facilitated the N2O reduction pathway. Consequently, MCAC decreased N2O emissions by 20%-27%. These findings offer valuable insights for optimizing MCAC strategies to mitigate N2O emissions.

Electrocatalytic Pathways and Efficiency of Cuprous Oxide (Cu2O) Surfaces in CO2 Electrochemical Reduction (CO2ER) to Methanol: A Computational Approach

Carbon dioxide (CO2) can be electrochemically, thermally, and photochemically reduced into valuable products such as carbon monoxide (CO), formic acid (HCOOH), methane (CH4), and methanol (CH3OH), contributing to carbon footprint mitigation. Extensive research has focused on catalysts, combining experimental approaches with computational quantum mechanics to elucidate reaction mechanisms. Although computational studies face challenges due to a lack of accurate approximations, they offer valuable insights and assist in selecting suitable catalysts for specific applications. This study investigates the electrocatalytic pathways of CO2 reduction on cuprous oxide (Cu2O) catalysts, utilizing the computational hydrogen electrode (CHE) model based on density functional theory (DFT). The electrocatalytic performance of flat Cu2O (100) and hexagonal Cu2O (111) surfaces was systematically analysed, using the standard hydrogen electrode (SHE) as a reference. Key parameters, including free energy changes (ΔG), adsorption energies (Eads), reaction mechanisms, and pathways for various intermediates were estimated. The results showed that CO2 was reduced to CO(g) on both Cu2O surfaces at low energies. However, methanol (CH3OH) production was observed preferentially on Cu2O (111) at ΔG = −1.61 eV, whereas formic acid (HCOOH) and formaldehyde (HCOH) formation were thermodynamically unfavourable at interfacial sites. The CO2-to-methanol conversion on Cu2O (100) exhibited a total ΔG of −3.38 eV, indicating lower feasibility compared to Cu2O (111) with ΔG = −5.51 eV. These findings, which are entirely based on a computational approach, highlight the superior catalytic efficiency of Cu2O (111) for methanol synthesis. This approach also holds the potential for assessing the catalytic performance of other transition metal oxides (e.g., nickel oxide, cobalt oxide, zinc oxide, and molybdenum oxide) and their modified forms through doping or alloying with various elements.

Steering CO2 Electroreduction to Methane Production Over Copper via Polymer‐Regulated Hydrolysis

AbstractCarbon dioxide (CO₂) electroreduction in aqueous electrolytes is a complex electrochemical process that involves the transfer of multiple electrons and protons, resulting in various reaction pathways and products. A critical step in this process is the dissociation of water, which provides protons and significantly affects *CO hydrogenation pathways, as well as hydrogen evolution. In this study, copper‐based catalysts are modified through in situ polymerization of dopamine to create intimate polymer coatings that regulate the surface water dissociation process. This modification leads to a notable shift in the product distribution of CO₂ electroreduction, from predominantly multicarbon compounds to methane, accompanied with the ratio of CH4/C2+ changing from 0.5 to 1.8. At high current densities, the polymer‐modified catalyst exhibited stable methane production with a Faradaic efficiency of up to 60%. Kinetic isotopic effects, in situ infrared spectroscopy, and theoretical calculations revealed that polydopamine plays a crucial role in altering product selectivity by regulating hydrolysis. This work signifies the importance of polymer‐regulated hydrolysis to steer the electrochemical CO2 reduction pathways.

Advances in Electrochemical Nitrite Reduction toward Nitric Oxide Synthesis for Biomedical Applications.

Nitric oxide (NO) is an essential molecule in biomedicine, recognized for its antibacterial properties, neuronal modulation, and use in inhalation therapies. The effectiveness of NO-based treatments relies on precise control of NO concentrations tailored to specific therapeutic needs. Electrochemical generation of NO (E-NOgen) via nitrite (NO2 -) reduction offers a scalable and efficient route for controlled NO production, while also addressing environmental concerns by reducing NO2 - pollution and maintaining nitrogen cycle balance. Recent developments in catalysts and E-NOgen devices have propelled NO2 - conversion, enabling on-demand NO production. This review provides an overview of NO2 - reduction pathways, with a focus on cutting-edge Fe/Cu-based E-NOgen catalysts, and explores the development of E-NOgen devices for biomedical use. Challenges and future directions for advancing E-NOgen technologies are also discussed.

Investigation of Diverse Urban Carbon Emission Reduction Pathways in China: Based on the Technology–Organization–Environment Framework for Promoting Socio-Environmental Sustainability

In the context of global carbon emissions and climate change, identifying context-specific low-carbon pathways for urban areas is critical for achieving socio-environmental sustainability. This study applies the technology–organization–environment (TOE) framework to examine the driving mechanisms and the diversity in carbon reduction pathways across 81 cities in China. Utilizing partial least squares structural equation modeling (PLS-SEM) and necessary condition analysis (NCA), this research assesses the roles of technological, organizational, and environmental drivers in urban carbon reduction. Fuzzy-set qualitative comparative analysis (fsQCA) is employed to uncover distinct carbon reduction pathways and causal asymmetries between cities. The findings reveal that technological, organizational, and environmental factors significantly drive carbon reduction, with technological and organizational factors playing the central roles. Environmental factors exert primarily indirect effects, interacting with technological and organizational drivers. This study categorizes cities into three distinct carbon reduction models: cities with high carbon-neutral potential primarily leverage technological innovation and energy efficiency optimization; cities with moderate potential integrate technology and policy, emphasizing green landscape planning to achieve balanced development; and cities with lower carbon reduction potential are mainly policy-driven, constrained by technological and resource limitations. This study underscores the role of computational modeling in providing valuable insights for the development of context-tailored carbon reduction strategies. It highlights the synergetic interactions among technological, organizational, and environmental factors, offering essential guidance for advancing sustainable development planning and facilitating the low-carbon transition of cities and communities.

Dynamic Simulation and Reduction Path of Carbon Emission in “Three-Zone Space”: A Case Study of a Rapidly Urbanizing City

Understanding the current and future net carbon emission trajectories in “Three-Zone Space” is crucial for China to promote the formation of a low-carbon development pattern in territorial space and realize carbon neutrality. Taking Wuhan as the study area, we developed carbon emission and sequestration inventories for “Three-Zone Space”. Key driving factors of net carbon emissions were analyzed using the logarithmic mean division index, and future emissions and sequestration under six scenarios were projected with a system dynamics model. The optimal emission reduction pathway was identified through the intelligent decision-making index analysis. Our results show that Wuhan’s net carbon emission increased from 18.589 Mt in 2000 to 42.794 Mt in 2020. The emissions during this period primarily came from urban production space and urban living space. Economic development is the primary factor contributing to the increase in net carbon emissions (36.412 Mt). The efficiency of territorial space utilization is the strongest mitigator of net carbon emissions, reducing net carbon emissions by 74.341 Mt (accounting for 42.06% of total emissions). The comprehensive scenario is the most effective for net carbon emission reduction in urban and ecological spaces, while the technological progress scenario provides the greatest reduction potential in agricultural spaces. These findings provide actionable insights for optimizing spatial planning, enhancing ecological restoration, and adopting low-carbon agricultural technologies to achieve targeted emissions reductions in “Three-Zone Space”. The results of this study can further provide scientific basis for the formulation of targeted emission reduction measures for “Three-Zone Space” and guide the construction of low-carbon territorial space patterns.

Research on the Carbon Footprint Accounting Method of Transformer’s Whole Life Cycle Under the Background of Double Carbon

In response to the existing gaps in the carbon footprint assessment framework for core electrical equipment transformers, which impedes power companies from effectively supporting low-carbon procurement of materials and products, this study proposes a novel evaluation method for transformer carbon footprints. This method comprehensively considers all stages of the transformer lifecycle, including manufacturing, transportation, installation, operation, and decommissioning. A review of mainstream carbon footprint accounting schemes, both domestic and international, is first presented, summarizing established accounting methods and calculation processes. The paper then introduces a novel, integrated carbon footprint accounting approach for transformers, covering the entire ‘cradle-to-grave’ lifecycle, along with an associated calculation model. This framework analyzes the carbon footprint composition across production, assembly, transportation, usage, and recycling stages for four commonly used, high-efficiency transformers at State Grid Xinjiang Electric Power Company, the carbon footprint of an oil-immersed 100 kVA/10 kV transformer is 2.353 × 106 kg CO2e, approximately half that of a conventional 100 kVA/10 kV transformer. Finally, the study provides recommendations for carbon reduction pathways for transformers, considering both functional substitution and technological carbon reduction strategies.

A study on the carbon emission reduction pathways of China’s digital economy from multiple perspectives

As the share of the digital economy’s output continues to rise each year, the emergence of new industries such as e-commerce, mobile payments, and cloud computing has opened new avenues for carbon emission reduction (CER). Based on panel data from 30 provinces in China, this article systematically analyzes the CER pathways of China’s digital economy (DE) from the perspectives of direct effects, indirect effects, threshold effects, and heterogeneity analysis. The main conclusions are as follows: (1) China’s DE has a significant CER effect. (2) The DE can indirectly reduce regional carbon emissions (CE) by industrial structures and technological innovation, with the mediating effect of technological innovation being more significant than that of industrial structure. (3) Urbanization has threshold effects on the CER effect of China’s DE. Under the influence of urbanization, there is an inverted U-shaped relationship between DE and CE. (4) Heterogeneity analysis finds that, compared to other types of provinces, the CER effect of DE is stronger in non-resource-based and economically developed provinces. (5) We propose five tailored recommendations for CER: fostering the synergistic development of the DE and industrial structure, strengthening the role of technological innovation, advancing urbanization and carbon reduction in a differentiated manner, formulating distinct policies for resource-based and non-resource-based provinces, and enhancing the construction of digital infrastructure in less-developed regions. This article not only establishes a more comprehensive connection between the DE and CER, but also reveals the differences in the role of technological innovation, industrial structure optimization, urbanization and other factors in the carbon reduction effect of the DE through the comparison of different paths and mechanisms.

Quantifying Socio-Regional Variability via Factor Analysis over China: Optimizing Residential Sector Emission Reduction Pathways

Policy synergy, the evidence-based coordination of public policies, can aid in more rapidly achieving air pollutant and carbon dioxide (CO2) emission reduction targets. Using logarithmic mean Divisia index (LMDI) decomposition, coupling coordination degree (CCD), and geographically and temporally weighted regression (GTWR) models, we analyzed the emission characteristics, drivers, and reduction pathways of residential air pollution across 30 Chinese provinces from 2001 to 2020. The southern provinces produced more air pollution than the northern provinces, with the gap widening after 2015. In the residential sector, energy emission factors (LMDI decomposition result, 686,681.9) and population size (14,331) had greater impacts on air pollutant emissions than the energy structure, energy intensity, synergies, or GDP per capita. The GTWR analysis of the CCD mechanism indicated that hydroelectricity and urbanization enhanced coupling coordination in the southeast. Meanwhile, in the west, coupling coordination was improved by R&amp;D investment, government spending on industrial pollution control, electricity consumption, per capita cropland, temperature, and urbanization. This analysis provides a valuable reference for optimizing emission reduction strategies.

A Deep Insight into the Microscopic Dynamics of the Electrode-Electrolyte Interface under Extreme Operating Conditions.

Understanding the interfacial dynamics during operation is critical for electrochemistry to make great advancements. However, breakthroughs on this topic under extreme conditions are very scarce. Here, as an example, we employ operando Raman spectroscopy to decode the interfacial dynamics of titanium electrolysis using a tailored instrument. Direct spectral evidence not only confirms the two-step reduction pathway and the key intermediate (TiF52-) in molten fluorides with high-temperature and strong-corrosion conditions but also unravels the origins of the undesirable shuttling effect of TiF52-, which are the sluggish reduction kinetics and outward diffusion behavior of TiF52-. Moreover, an insightful atomic scenario of the electric double layer (EDL) under varied potentials has been established. These quantitative understandings guide us to design economical-feasible regulation protocols─the rational combination of a high-concentration, low-valence Ti-ion electrolyte with appropriate applied potential. Impressively, the current efficiency is greatly promoted from 27.7 to 81.8% using our proposed protocols. Finally, this work also demonstrates a bottom-up technological research paradigm for extreme electrochemistry based on mechanism insights rather than phenomenological findings, which will accelerate the advancement of extreme electrochemistry.

A reduction-secretion system contributes to roxarsone (V) degradation and efflux in Brevundimonas sp. M20

Roxarsone (V) (Rox(V)) is an organoarsenical compound that poses significant risks to aquatic ecosystems and various diseases. Reducing trivalent 3-amino-4-hydroxyphenylarsonic acid (HAPA(III)) offers a competitive advantage; however, it leads to localized arsenic contamination, which can disrupt the soil microbiome and impede plant growth. Three genes, BsntrA, arsC2, and BsexpA, encoding nitroreductase, arsenate reductase, and MFS transporter, respectively, were identified in the Rox(V)-resistant strain Brevundimonas sp. M20. A three-step approach, including nitroreduction, As(V) reduction, and HAPA(III) secretion, which is responsible for roxarsone(V) resistance, was subsequently confirmed. Moreover, the flavonoid compound baicalin occupied the HAPA(III) delivery space and grabbed the R127 residues via stronger interactions. This steric hindrance prevented the transportation of HAPA(III) by BsexpA to the extracellular space. These results demonstrate a new Rox(V) reduction pathway, providing a potential efflux pump inhibitor to trap more toxins.

In Situ Spectroscopic Probing of the Hydroxylamine Pathway of Electrocatalytic Nitrate Reduction on Iron-Oxy-Hydroxide.

Crystalline γ-FeO(OH) dominantly possessing ─OH terminals (𝛾-FeO(OH)c), polycrystalline γ-FeO(OH) containing multiple ─O, ─OH, and Fe terminals (𝛾-FeO(OH)pc), and α-Fe2O3 majorly containing ─O surface terminals are used as electrocatalysts to study the effect of surface terminals on electrocatalytic nitrate reduction reaction (eNO3RR) selectivity and stabilization of reaction intermediates. Brunauer-Emmett-Teller analysis and electrochemically determined surface area suggest a high active surface area of 117.79 m2 g-1 (ECSA: 0.211 cm2) for 𝛾-FeO(OH)c maximizing the surface accessibility for nitrate adsorption and exhibiting selective eNO3RR to NH3 at pH 7 with a yield rate 18.326mg h-1 cm-2, >85% Faradaic efficiency (FE), and at least nine-times catalyst-recyclability. 15N- and D-labeling combined with in situ IR and Raman studies validate the adsorption of nitrate ions on the ─OH terminals of 𝛾-FeO(OH)c and the generation of nitrite and hydroxyl amine as eNO3RR intermediates. A kinetic isotope effect (KIE) value of 2.1 indicates H2O as the proton source and proton-coupled electron transfer as the rate-limiting step. The rotating-ring disk electrochemical (RRDE) study and subsequent Koutecký-Levich analysis reveal the electron-transfer rate constant (k) for the 2e- reduction of nitrate to nitrite is 5.7 × 10-6cm s-1. This study provides direct evidence of the hydroxyl amine formation as the dominant pathway of eNO3RR on γ-FeO(OH).