High Methane Research Articles

Bottom‐Up Strategy to Enhance Long‐Range Order of Poly(Heptazine Imide) Nanorods for Efficient Photocatalytic CO2 Methanation

AbstractPoly(heptazine imide) (PHI), one of the crystalline or long‐range ordered allotropes of polymeric carbon nitride, is a promising polymeric photocatalyst; however, preparation of highly crystalline PHI remains a challenge. Herein, through a bottom‐up strategy involving repair of structural defects and increase of specific surface area of melon precursor, we prepared PHI nanorods with dramatically improved long‐range order. The resulting PHI exhibited a shift of product selectivity in CO2 photoreduction from CO to CH4 with a high methanation activity in contrast to the pristine PHI with relatively low long‐range order. The improvement of long‐range order for PHI remarkably enhanced the separation efficiency and transfer kinetics of photogenerated charges as well as the adsorption for *CO intermediate. This study revealed the relationship between the precursor structure and PHI crystal growth in ionothermal synthesis, and also showcased the great potential of highly crystalline PHI in artificial photosynthesis.

Estimating methane emissions from the waste sector in southern ontario using atmospheric measurements

ABSTRACT We estimate methane emissions rates for urban waste treatment facilities from mobile in situ atmospheric concentration measurements using an inverse Gaussian plume methodology at facilities in Southern Ontario, Canada. We use these estimated emissions rates to investigate, update, and improve the existing high resolution methane inventories at the facility level for waste sources throughout the Greater Toronto Area and Southwestern Ontario. Our measurements encompass tens of thousands of kilometers worth of mobile survey data collected over 7 years, encompassing more than 650 downwind transects where we surveyed 14 active landfills, 11 closed landfills, 2 organic waste processing facilities, 3 open air windrow compost facilities, and 11 water resource recovery facilities across our study region. These sources account for 77% of the active landfills within Southern Ontario, which is estimated in inventories to be the largest source of methane emissions in the region. Within the Greater Toronto Area (GTA) megacity, the measured facilities represent about 52% of the total inventoried non-wetland methane emissions. We find that emissions from closed landfills are lower than inventory estimates, with significant implications for the methane budget in the GTA. We update the Facility Level and Area Methane Emissions for the GTA inventory with our measured emissions rates, which results in a 54% decline in the solid waste emissions, effecting a 35% lower estimate for the total anthropogenic methane emissions in the region. We attribute the bulk of this difference to a single facility: the Keele Valley landfill. Our atmospheric measurements also serve as a novel metric for evaluating the discrepancies between four facility level, and two high resolution gridded methane emissions inventories. Based on linear regressions of our measured emissions versus inventoried values, we find that the facility level first order decay model maintained by Environment and Climate Change Canada (ECCC) to be the most consistent with our measured emissions rates at landfills and the self-reported emissions to the Greenhouse Gas Reporting Program of ECCC to be the least consistent with our measurements.

Bottom-Up Strategy to Enhance Long-Range Order of Poly(Heptazine Imide) Nanorods for Efficient Photocatalytic CO2 Methanation.

Poly(heptazine imide) (PHI), one of the crystalline or long-range ordered allotropes of polymeric carbon nitride, is a promising polymeric photocatalyst; however, preparation of highly crystalline PHI remains a challenge. Herein, through a bottom-up strategy involving repair of structural defects and increase of specific surface area of melon precursor, we prepared PHI nanorods with dramatically improved long-range order. The resulting PHI exhibited a shift of product selectivity in CO2 photoreduction from CO to CH4 with a high methanation activity in contrast to the pristine PHI with relatively low long-range order. The improvement of long-range order for PHI remarkably enhanced the separation efficiency and transfer dynamics of photogenerated charges as well as the adsorption capacity for *CO intermediate. This study revealed the relationship between the precursor structure and PHI crystal growth in ionothermal synthesis, and also showcased the great potential of highly crystalline PHI in artificial photosynthesis.

Biofeed through bioconversion process with the engineered methyl-microbium buryatense strain 5GBC1-RO1

This study presents a novel approach to mitigate methane emissions while simultaneously addressing the growing demand for sustainable animal feed through the development of an engineered methanotrophic strain, Methylomicrobium buryatense 5GB1C-RO1. Utilizing advanced genetic engineering techniques, including CRISPR/Cas9 and horizontal gene transfer, we have optimized the ribulose monophosphate (RuMP) cycle and enhanced oxidase activity in this strain. The bioconversion process is facilitated by innovative bioreactor designs, including Two-Phase Partitioning Bioreactors (TPPBs) and Inverse Membrane Bioreactors (IMBRs), which significantly improve methane solubility and mass transfer. Through metabolic flux analysis and computational modeling, we have achieved high biomass yields and efficient methane utilization. The resulting biofeed demonstrates a superior nutritional profile, with optimized macronutrient content and essential components. This integrated approach not only contributes to greenhouse gas mitigation but also offers a promising solution for sustainable animal nutrition. Our findings suggest that the 5GB1C-RO1 strain and associated bioprocesses have the potential to revolutionize both environmental protection and agricultural sustainability.

Anaerobic decomposition of substandard pet food as a raw material source for producing hydrogen from methane

A potential raw material for producing hydrogen (the main carrier for the accumulation, storage and transportation of energy) is methane from biogas. An approach to producing biogas with a high methane content (69–72%) from waste commercial dry and wet food for dogs and cats under mesophilic conditions has been demonstrated. For 27–28 days under anaerobic conditions, the degree of biotransformation of waste was 60–88%. As a result of mineralization of watered organic waste, the content of ammonium nitrogen and phosphorus in the form of phosphates amounted to 676–887 mgNH4+/l and 77–160 mgPO43-/l, respectively. In anaerobically treated effluent, accumulation of sulfide ions up to 22 mg/l was observed. The solid sediment and anaerobically treated effluent (liquid fraction) obtained upon completion of the biotransformation of pet food waste are a potential organic fertilizer for agricultural needs, and methane from biogas is a raw material for producing hydrogen and pure carbon for the needs of the nanoindustry.

High storage capacity and rapid methane hydrate formation using low concentrations of a new surfactant: A mimic of SDS and amino acid scaffold

The development of efficient, non-foaming promoters is essential for advancing the industrial applications of solidified gas hydrates in carbon capture, natural gas storage, and transportation. In this study, a novel surfactant, containing sulfonate, amide, and carboxyl groups (SSAC), was introduced as a promoter for methane hydrate formation. SSAC was synthesized by integrating the chemistries of amino acids and sodium dodecyl sulfate (SDS), distinguishing it from existing promoters. High-pressure autoclave experiments demonstrated that SSAC significantly enhanced the kinetics of methane hydrate formation, at a low concentration of 5 ppm, achieving a maximum water-to-hydrate conversion of 85.2 %, equivalent to a storage capacity of 163.5 v/v in deionized water. Increasing the SSAC concentration to 500 ppm resulted in an impressive conversion rate of 94.6 % and a storage capacity of 181.6 v/v. Methane recovery was accomplished without foaming within 15 min during hydrate dissociation at room temperature, addressing a critical challenge in current hydrate-based storage systems. Molecular dynamics simulations further revealed that SSAC molecules act as collectors for methane molecules in solution, thereby enhancing the rate of hydrate growth and increasing the number of hydrate cavities. Notably, SSAC exhibited a biodegradation level of 41 % after 28 days, indicating its potential for natural degradation and environmental compatibility. This combination of low concentration efficiency, foam-free formation, environmental sustainability, and enhanced methane collection is unprecedented in the current literature, highlighting the innovative nature of this work. These findings suggest that the integration of amino acid structures with anionic surfactants offers a promising strategy for designing effective promoters, with significant implications for energy storage, seawater desalination, and carbon capture technologies.

Surface Sulfurization of Cubic Cu2O to Form Cu2S Nanostructure-Decorated Catalysts for Light-Enhanced Electrocatalytic H2 Evolution and Photocatalytic CO2 Reduction.

Developing highly efficient bifunctional catalysts for electrocatalysis and photocatalysis suffers from sluggish charge transfer and poor photo-to-electric conversion rate. Herein, micro-sized Cu2O cubes were initially prepared for subsequent transformation into Cu2O@Cu2S core-shell structures by a slight surface sulfurization. The formation of nanostructured Cu2S thin layer at Cu2O surface can endow an immediate charge separation and migration under light irradiation, leading to high surface photovoltages (SPV, 18-30 mV). As a result, the as-prepared Cu2O@Cu2S catalysts exhibited reduced overpotentials (η, only 86 mV is required for the optimized sample to achieve a current density of 10 mA cm-2) for H2 evolution with good cycling stability in electrocatalytic water splitting. Meanwhile, a high methane (CH4) production rate of 30.3 μmol h-1 g-1 can be delivered from the optimized Cu2O@Cu2S sample when used for photocatalytic CO2 reduction. This work has provided a strategy to prepare bifunctional catalysts with improved photoelectric properties for photo/electrocatalytic applications.

Drill‐seeding rice reduces global warming potential but increases nitrogen loss potential compared to water‐seeding

AbstractFlooded rice (Oryza sativa L.) systems are critical for global food security but contribute significantly to anthropogenic greenhouse gas (GHG) emissions due to high methane (CH4) emissions from anaerobic soils. Drill‐seeding (DS) rice, which in California includes early‐season irrigation flushes to establish the rice, has been shown to reduce CH4 emissions compared to water‐seeded (WS) systems. The effect of these early‐season flushes on nitrogen (N) fertilizer losses and nitrous oxide (N2O) emissions, however, is not well understood. In a 2‐year study, we quantitatively compared DS to WS systems with respect to their global warming potential (GWP) (CH4 + N2O in CO2 eq.), nitrate (NO3−) accumulation during flushes, and crop N‐uptake. Despite 0.68 kg ha−1 more N2O–N emissions in the DS system, GWP was 3700 CO2 eq. kg ha−1, a 42% reduction compared to 6340 CO2 eq. kg ha−1 in the WS system. This was due to a 46% reduction in CH4 in the DS (94.5 CH4–C kg ha−1) relative to the WS (175.7 CH4–C kg ha−1) system. Nitrate accumulation in the DS system amounted to 26.2 kg NO3–N ha−1, and subsequent N losses via denitrification likely contributed to the 22.4 kg N ha−1 less crop N‐uptake in the DS system. These results suggest that DS rice has potential for improved environmental impact via GWP reductions but will require increased N inputs. Future efforts should focus on reducing N losses, which have a negative economic impact for the farmer and contribute to N2O emissions.

Influence of Dopants on Pt/Al2O3-Based Monolithic Catalysts for Autothermal Oxidative Coupling of Methane

Autothermal oxidative coupling of methane (OCM) is a highly attractive approach for methane utilization. If platinum-based catalysts are operated in short-contact-time reactors with high space velocities, high methane conversion can be achieved. Using a 1 wt.% Pt/Al2O3 catalyst as a benchmark, the present study elucidates how different dopants, namely Ni, Sn, and V2O5, affect the OCM reaction. Kinetic catalyst tests reveal that acetylene (C2H2) is the predominant C2 product, irrespective of the catalyst formulation or operation conditions. Furthermore, the use of bimetallic catalysts allows either for the maintenance or even the improvement of the C2 selectivity during OCM, which is attributed to synergistic effects that occur when expensive Pt is partially replaced by cheaper dopants. In particular, the 1 wt.% Pt/Al2O3 reference catalyst yielded a maximum C2 selectivity of 8.2%, whereas the best-performing doped sample 0.25 wt.% Pt 0.75 wt.% V2O5/Al2O3 yielded a total C2 selectivity of 11.3%.

Stable heterometallic metal-organic frameworks and pellet composites for low-temperature natural gas storage

Liquefied natural gas coupled with adsorbed natural gas charging (LNG-ANG) offers an efficient solution for recycling boil-off gas, providing a promising strategy for the competent storage and transportation of natural gas. The key challenge in LNG-ANG coupling systems is identifying adsorbents that exhibit superior methane adsorption performance and excellent stability under cryogenic conditions (∼159 K). In this work, we systematically investigated the methane adsorption performance of a stable metal–organic framework, PCN-250-Fe2Ni, under LNG-ANG related conditions. The results demonstrated that PCN-250-Fe2Ni exhibited a high methane capacity of 286 cm3 (standard temperature and pressure, STP) cm−3 (0.227 g g−1) at 6 bar/159 K. Furthermore, the pellet composite of PCN-250-Fe2Ni and polyvinyl butyral also displayed a high methane adsorption capacity with excellent cycling stability. Combined with grand canonical Monte Carlo simulations, our findings revealed that the cage-type pores serve as initial methane adsorption sites, followed by the channel-type pores, both of which contribute to the framework’s high low-temperature methane storage performance at saturation.

Management of Tanning Waste from Leather Processing by Anaerobic Digestion Using a Dynamic Method on a Semi-Technical Scale

In the context of climate policy, measures are being taken around the world to reduce pollution. These have been intensified in the areas of transport, industry, and energy, with the goal of zero emissions. The role of the biogas plant in energy transition and as a waste treatment plant for disposal is very important. This article describes research on a dynamic anaerobic digestion (AD) process plant. The subject of this study was leather shavings, which is a problematic waste. The research presented here is intended to demonstrate the decomposition of the flesh in the process, to confirm its biogas yield, and to evaluate the biological and technical parameters of the process. High biochemical stability was achieved for each of the tests evaluated, and no specific technical requirements were demonstrated. The only technical aspect to be addressed during operation was sedimentation, which can be solved by preparing the mixture earlier or by changing the mixing method. This made it reasonable to investigate the material further in the context of an industrial project. The characteristics of protein degradation in the AD process resulted in a high methane content in the biogas, above 65%. It was also observed that the long conditioning time of biogas in the gas cushion favourably affected the proportion of methane in biogas. Analytical results confirmed 77.5% methane content, which was a very good result. This paper presents the results of a surprising effect of chromium, primarily Cr (III), on the performance of anaerobic digestion.

Intrinsic reactivity of stoichiometric IrO2(1 1 0) surface toward oxidative coupling of methane

This study investigates the oxidative coupling of methane on the IrO2(110) surface using TPRS simulations informed by DFT-derived data. We discover that the efficiency of the IrO2(110) surface in generating ethylene is strongly influenced by methane surface coverage. Our simulations reveal that the presence of surface hydroxyl group enhances the yield of C2+ species from methane oxidation, but this effect is counteracted at high methane coverages due to the accelerated formation of CH2OH. In addition, the study reveals that slight modifications in energy barriers at the branching point (C2H4 formation vs. CH2OH formation) significantly affect C2H4(g) production from the simulation, underscoring the importance of precise energetic data for accurate catalytic reaction predictions. The results have broader implications for reactions and catalysts where branching point selectivity determines high-value product yields. Thus, combining surface science with computational analysis is crucial for accurately determining energy profiles of key steps at the branching points.

Comparison of pyrolysis and anaerobic digestion processes for wheat straw biomass

Due to the growing interest in using biomass as a renewable energy source, this study presents a comparative analysis between two prominent biomass conversion technologies—anaerobic digestion and biomass pyrolysis—focused on wheat straw biomass. The objective of this study is to evaluate and compare the efficiency, energy output, and environmental impact. Anaerobic digestion was performed under mesophilic conditions (35 ± 0.5 °C) using the biochemical methanogenic potential (BMP) methodology. Pyrolysis was conducted through thermogravimetric analysis (TGA) to determine the thermal behaviour and kinetic parameters of the biomass. Biogas production led to better energetic results as high methane yields of over 11 mL CH₄ g⁻¹ VS were obtained. Additionally, the integration of both processes was considered by subjecting digestate from anaerobic digestion to pyrolysis process. Key findings demonstrate that the activation energy (Ea) for wheat straw ranged from 166.49 to 176.42 kJ·mol−1 across different kinetic methods, indicating its suitability for pyrolysis. In contrast, digestates exhibited significantly lower activation energies, with 1-week, 2-weeks, and 3-weeks digestates showing ranges of 53.27–60.79 kJ·mol−1, 38.69–46.86 kJ·mol−1, and 46.29–72.34 kJ·mol−1, respectively. These results suggest that anaerobic digestion not only produces biogas but also yields a byproduct with potential for efficient pyrolytic conversion suggesting opportunities for integrated waste management and renewable energy production systems.

Methane distribution above the Emperor Seamount chain

Dissolved methane (CH4) concentrations were measured in the water column at 25 stations along the four sections above Koko and Jingu guyots (the southern part of Emperor Seamount chain). The measured methane concentrations were relatively low (1–6.5 nM). The patterns of CH4 vertical distributions over Koko and Jingu were different. The greatest dissolved methane concentrations (6.5 nM) were found in the near-bottom layer (357 m) above the Koko summit. For Koko guyot, the greatest CH4 content (3.9–6.5 nM) was mainly associated with the subsurface (10–300 m) layer above the summit. However, another methane plume (6 nM) was detected at 1000 m on the western slope of the guyot. We propose that methane maximum was caused by the influence of the Kuroshio Extension or deep eddies. The CH4 distribution over Jingu gyuot was similar to that in open ocean waters. The greatest methane concentrations (3.8–6 nM) were found in the subsurface layers above the summit. Methane exceeded atmospheric equilibrium concentration in the surface (5–52 % supersaturation) layer for both Koko and Jingu. The methane content and supersaturation level in the subsurface layer was at least two times higher than previously measured values for the open ocean. We believe that the high methane and supersaturation level was caused by enhanced methanogenesis in the water column above the seamounts. The estimated methane flux to the atmosphere varied from 1.4 to 16.3 μmol m−2 day−1 for Koko and from 0.5 to 6.5 μmol m−2 day−1 for Jingu, respectively. The average fluxes calculated for Koko (8.37 μmol m−2 day−1) and Jingu (2.8 μmol m−2 day−1) were significantly greater than the average flux for open and coastal oceans. Given the substantial methane atmospheric contributions, the global methane budget should be reconsidered.

Vulnerability of Arctic-Boreal methane emissions to climate change

The rapid warming of the Arctic-Boreal region has led to the concern that large amounts of methane may be released to the atmosphere from its carbon-rich soils, as well as subsea permafrost, amplifying climate change. In this review, we assess the various sources and sinks of methane from northern high latitudes, in particular those that may be enhanced by permafrost thaw. The largest terrestrial sources of the Arctic-Boreal region are its numerous wetlands, lakes, rivers and streams. However, fires, geological seeps and glacial margins can be locally strong emitters. In addition, dry upland soils are an important sink of atmospheric methane. We estimate that the net emission of all these landforms and point sources may be as much as 48.7 [13.3–86.9] Tg CH4 yr−1. The Arctic Ocean is also a net source of methane to the atmosphere, in particular its shallow shelves, but we assess that the marine environment emits a fraction of what is released from the terrestrial domain: 4.9 [0.4–19.4] Tg CH4 yr−1. While it appears unlikely that emissions from the ocean surface to the atmosphere are increasing, now or in the foreseeable future, evidence points towards a modest increase from terrestrial sources over the past decades, in particular wetlands and possibly lakes. The influence of permafrost thaw on future methane emissions may be strongest through associated changes in the hydrology of the landscape rather than the availability of previously frozen carbon. Although high latitude methane sources are not yet acting as a strong climate feedback, they might play an increasingly important role in the net greenhouse gas balance of the Arctic-Boreal region with continued climate change.

Single-Crystalline 3D Covalent Organic Frameworks with Exceptionally High Specific Surface Areas and Gas Storage Capacities.

Single-crystalline covalent organic frameworks (COFs) are highly desirable toward understanding their pore chemistry and functions. Herein, two 50-100 μm single-crystalline three-dimensional (3D) COFs, TAM-TFPB-COF and TAPB-TFS-COF, were prepared from the condensation of 4,4',4″,4‴-methanetetrayltetraaniline (TAM) with 3,3',5,5'-tetrakis(4-formylphenyl)bimesityl (TFPB) and 3,3',5,5'-tetrakis(4-aminophenyl)bimesityl (TAPB) with 4,4',4″,4‴-silanetetrayltetrabenzaldehyde (TFS), respectively, in 1,4-dioxane under the catalysis of acetic acid. Single-crystal 3D electron diffraction reveals the triply interpenetrated dia-b networks of TAM-TFPB-COF with atom resolution, while the isostructure of TAPB-TFS-COF was disclosed by synchrotron single-crystal X-ray diffraction and synchrotron powder X-ray diffraction with Le Bail refinements. The nitrogen sorption measurements at 77 K disclose the microporosity nature of both activated COFs with their exceptionally high Brunauer-Emmett-Teller surface areas of 3533 and 4107 m2 g-1, representing the thus far record high specific surface area among imine-bonded COFs. This enables the activated COFs to exhibit also the record high methane uptake capacities up to 28.9 wt % (570 cm3 g-1) at 25 °C and 200 bar among all COFs reported thus far. This work not only presents the structures of two single-crystalline COFs with exceptional microporosity but also provides an example of atom engineering to adjust permanent microporous structures for methane storage.

Vitreous silica supported metal catalysts for direct non-oxidative methane coupling

Direct non-oxidative methane coupling (NMC) transforms methane into valuable chemicals and hydrogen, which is a promising pathway to boost industrial decarbonization. The reaction, however, is challenged by high C-H bond activation temperature, catalyst coking, and low selectivity towards hydrocarbon products. Here we studied the efficacy of five vitreous silica supported 3d transition metal (Mn, Fe, Co, Ni, and Cu) catalysts (denoted as M/SiO2-v) for NMC. These catalysts were prepared by flame fusion of mixtures of quartz and metal silicate precursors. The metal species in the as-synthesized catalysts were fully or partially oxidized, with their stability following the order of Mn > Fe ≈ Co > Ni > Cu in the NMC reaction. The Cu species has low methane reaction rate, due to the high adsorption and dissociation energies of methane. The Mn and Ni species have high methane reaction and coke formation rates, which is supported by easy kinetics of methane deep dehydrogenation to carbon. In contrast, Fe and Co species showed the best hydrocarbon product selectivity. Particularly, the Co species emerged as the optimal catalyst for NMC, showcasing a balanced methane activation, hydrocarbon formation, and low coke yield. The relationship between the evolved metal species under reaction conditions and their NMC performance was discussed. The present study screens and provides effective catalyst formulations for NMC reactions.

From lab to industry: Scaling-up Fe-Ni bimetallic nano oxygen carrier for mid-temperature methane chemical looping reforming

Chemical looping methane reforming has emerged as a promising avenue to produce blue hydrogen. Currently, satisfactory CH4 conversion and H2 productivity typically requires reaction temperature above 800 °C, bringing challenges for industrial reactor design and energy conservation. To realize high chemical looping methane reforming performance at low temperature, a Fe-Ni bimetallic nano oxygen carrier was presented, along with the workflow and platform for scaled-up synthesis of the oxygen carrier. On account of the synergy of nanoscale Fe-Ni species, the operating temperature could be lowered to 500–600 °C. The lab-scale oxygen carrier converted >90 % CH4 and produced 3.5 H2 per CH4 molecule with 80–82 % outlet H2 purity at 575–600 °C. The 10-kg scale synthesized oxygen carrier powder exhibited >90 % CH4 conversion, >78 % H2 purity and produced 2.8–3.5 H2 per CH4, with performance penalty from scaling up controlled within 5 %. After shaping and calcination, the 10-kg oxygen carrier beads still produced 2.8 H2 from per CH4 molecule with >70 % H2 purity. Longevity test revealed the 10-kg powder and beads as stable in phase, morphology, and redox activity over 110 cycles. Experiments of variable operating conditions found that the 10-kg oxygen carriers can meet industrial requirements of H2 production at >550 °C, with low steam/carbon ratio favored by 10-kg beads. Further analysis attributed the performance distinction of 10-kg beads to its lower surface area, reduction extent and steam affinity, compared to those of the lab-scale and 10-kg powders. These findings contributed to the mid-temperature chemical looping methane reforming by bridging laboratory practices and industrial application.

Continuous augmentation of anaerobic digestion with electroactive microorganisms: Performance and stability

The performance and stability of a bioelectrochemical anaerobic digester (BeAD), continuously augmented with electroactive microorganisms (EAMs), were investigated. The BeAD showcased superior performance, sustaining the high COD removal efficiency and methane production rate of 76.5 % and 0.67 L/(L.d), respectively, in a stable state. Prominently, it exhibited remarkable resilience under hydraulic and organic shock loads, adeptly recuperating from disturbances up to 1000 % of its stable condition. This resilience of up to 300 % shock load was driven by increased levels of electron transport components such as quinones and riboflavins, which act as electron shuttles. However, after extreme shock exposures from 500 % to 1000 %, despite the spike in inhibitory by-products such as humic acids and ammonia, the upregulation of the mtr complex was pivotal in recovering and sustaining methane production. These insights emphasize the BeAD’s capability to bolster both performance and stability, thereby providing a potent strategy for practical application of bioelectrochemical systems.

Microbial communities and metagenomes in methane-rich deep coastal sediments

Coastal sediments are rich in embedded recalcitrant organic carbons that are biotransformed into methane. In this study, gas composition (carbon dioxide, methane and nitrogen) and chemical indicators (total nitrogen, total carbon, and total sulfate) were examined in five deep sediment cores (up to 130 m in length) obtained from the Hangzhou Bay. The V3-V4 region of the 16S rRNA gene amplicons was amplified and sequenced for the prokaryotic community analysis. The species composition, along with the physicochemical factors of the sediments, revealed a strong correlation with methane content in one of the sediment cores. We then obtained metagenomes of the two sediment samples selected for their high methane content and enrichment of methanogenic Bathyarchaeota with phylogenetic evidence. A total of 27 draft genomes were retrieved through metagenomic binning methodologies and were classified into Bathyarchaeota, Asgard archaea, Planctomycetes, and other microbial groups. The data provided are valuable for understanding the relationship between methane generation and microbial community composition in deep sediment core samples from coastal to marine environments.