Showing papers on "Methane published in 2017"

Direct Conversion of Methane to Value-Added Chemicals over Heterogeneous Catalysts: Challenges and Prospects

Abstract: The quest for an efficient process to convert methane efficiently to fuels and high value-added chemicals such as olefins and aromatics is motivated by their increasing demands and recently discovered large reserves and resources of methane. Direct conversion to these chemicals can be realized either oxidatively via oxidative coupling of methane (OCM) or nonoxidatively via methane dehydroaromatization (MDA), which have been under intensive investigation for decades. While industrial applications are still limited by their low yield (selectivity) and stability issues, innovations in new catalysts and concepts are needed. The newly emerging strategy using iron single sites to catalyze methane conversion to olefins, aromatics, and hydrogen (MTOAH) attracted much attention when it was reported. Because the challenge lies in controlled dehydrogenation of the highly stable CH4 and selective C–C coupling, we focus mainly on the fundamentals of C–H activation and analyze the reaction pathways toward selective rou...

Visible-light-driven methane formation from CO 2 with a molecular iron catalyst

Abstract: An iron tetraphenylporphyrin complex is shown to catalyse the reduction of carbon dioxide to methane upon visible light irradiation at ambient temperature and pressure. Converting CO2 into fuel or feedstock chemicals could reduce fossil fuel consumption and climate changing CO2 emissions, but a major stumbling block is the lack of efficient and selective catalysts for such conversions. Heng Rao et al. report that an iron tetraphenylporphyrin complex that is known as the most efficient and selective molecular catalyst for converting CO2 to CO can also catalyse the reduction of CO2 to methane upon visible light irradiation at ambient temperature and pressure. The overall performance makes the system unsuitable for practical applications, but the basic principles by which it operates might guide the development of more efficient catalysts for the production of solar fuels from CO2 under mild conditions. Converting CO2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO2 emissions1,2. One strategy aims for electrochemical conversions powered by electricity from renewable sources3,4,5, but photochemical approaches driven by sunlight are also conceivable6. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals7. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare8,9,10,11,12,13,14,15,16,17. Here we show that an iron tetraphenylporphyrin complex functionalized with trimethylammonio groups, which is the most efficient and selective molecular electro- catalyst for converting CO2 to CO known18,19,20, can also catalyse the eight-electron reduction of CO2 to methane upon visible light irradiation at ambient temperature and pressure. We find that the catalytic system, operated in an acetonitrile solution containing a photosensitizer and sacrificial electron donor, operates stably over several days. CO is the main product of the direct CO2 photoreduction reaction, but a two-pot procedure that first reduces CO2 and then reduces CO generates methane with a selectivity of up to 82 per cent and a quantum yield (light-to-product efficiency) of 0.18 per cent. However, we anticipate that the operating principles of our system may aid the development of other molecular catalysts for the production of solar fuels from CO2 under mild conditions.

The interaction of climate change and methane hydrates

Abstract: Gas hydrate, a frozen, naturally-occurring, and highly-concentrated form of methane, sequesters significant carbon in the global system and is stable only over a range of low-temperature and moderate-pressure conditions. Gas hydrate is widespread in the sediments of marine continental margins and permafrost areas, locations where ocean and atmospheric warming may perturb the hydrate stability field and lead to release of the sequestered methane into the overlying sediments and soils. Methane and methane-derived carbon that escape from sediments and soils and reach the atmosphere could exacerbate greenhouse warming. The synergy between warming climate and gas hydrate dissociation feeds a popular perception that global warming could drive catastrophic methane releases from the contemporary gas hydrate reservoir. Appropriate evaluation of the two sides of the climate-methane hydrate synergy requires assessing direct and indirect observational data related to gas hydrate dissociation phenomena and numerical models that track the interaction of gas hydrates/methane with the ocean and/or atmosphere. Methane hydrate is likely undergoing dissociation now on global upper continental slopes and on continental shelves that ring the Arctic Ocean. Many factors—the depth of the gas hydrates in sediments, strong sediment and water column sinks, and the inability of bubbles emitted at the seafloor to deliver methane to the sea-air interface in most cases—mitigate the impact of gas hydrate dissociation on atmospheric greenhouse gas concentrations though. There is no conclusive proof that hydrate-derived methane is reaching the atmosphere now, but more observational data and improved numerical models will better characterize the climate-hydrate synergy in the future.

Selective anaerobic oxidation of methane enables direct synthesis of methanol

Abstract: Direct functionalization of methane in natural gas remains a key challenge. We present a direct stepwise method for converting methane into methanol with high selectivity (~97%) over a copper-containing zeolite, based on partial oxidation with water. The activation in helium at 673 kelvin (K), followed by consecutive catalyst exposures to 7 bars of methane and then water at 473 K, consistently produced 0.204 mole of CH3OH per mole of copper in zeolite. Isotopic labeling confirmed water as the source of oxygen to regenerate the zeolite active centers and renders methanol desorption energetically favorable. On the basis of in situ x-ray absorption spectroscopy, infrared spectroscopy, and density functional theory calculations, we propose a mechanism involving methane oxidation at CuII oxide active centers, followed by CuI reoxidation by water with concurrent formation of hydrogen.

Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts

Abstract: An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid, which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. We find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolite-supported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60-100 per cent. We anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other useful chemicals.

Controlling guest conformation for efficient purification of butadiene

Abstract: Conventional adsorbents preferentially adsorb the small, high-polarity, and unsaturated 1,3-butadiene molecule over the other C4 hydrocarbons from which it must be separated. We show from single-crystal x-ray diffraction and computational simulation that a hydrophilic metal-organic framework, [Zn2(btm)2], where H2btm is bis(5-methyl-1H-1,2,4-triazol-3-yl)methane, has quasi-discrete pores that can induce conformational changes in the flexible guest molecules, weakening 1,3-butadiene adsorption through a large bending energy penalty. In a breakthrough operation at ambient temperature and pressure, this guest conformation-controlling adsorbent eluted 1,3-butadiene first, then butane, butene, and isobutene. Thus, 1,3-butadiene can be efficiently purified (≥99.5%) while avoiding high-temperature conditions that can lead to its undesirable polymerization.

The Direct Catalytic Oxidation of Methane to Methanol-A Critical Assessment.

Abstract: Despite the large number of disparate approaches for the direct selective partial oxidation of methane, none of them has translated into an industrial process. The oxidation of methane to methanol is a difficult, but intriguing and rewarding, task as it has the potential to eliminate the prevalent natural gas flaring by providing novel routes to its valorization. This Review considers the synthesis of methanol and methanol derivatives from methane by homogeneous and heterogeneous pathways. By establishing the severe limitations related to the direct catalytic synthesis of methanol from methane, we highlight the vastly superior performance of systems which produce methanol derivatives or incorporate specific measures, such as the use of multicomponent catalysts to stabilize methanol. We thereby identify methanol protection as being indispensable for future research on homogeneous and heterogeneous catalysis.

Aqueous Au-Pd colloids catalyze selective CH4 oxidation to CH3OH with O2 under mild conditions

Abstract: The selective oxidation of methane, the primary component of natural gas, remains an important challenge in catalysis. We used colloidal gold-palladium nanoparticles, rather than the same nanoparticles supported on titanium oxide, to oxidize methane to methanol with high selectivity (92%) in aqueous solution at mild temperatures. Then, using isotopically labeled oxygen (O2) as an oxidant in the presence of hydrogen peroxide (H2O2), we demonstrated that the resulting methanol incorporated a substantial fraction (70%) of gas-phase O2. More oxygenated products were formed than the amount of H2O2 consumed, suggesting that the controlled breakdown of H2O2 activates methane, which subsequently incorporates molecular oxygen through a radical process. If a source of methyl radicals can be established, then the selective oxidation of methane to methanol using molecular oxygen is possible.

Key Findings of the World’s First Offshore Methane Hydrate Production Test off the Coast of Japan: Toward Future Commercial Production

Abstract: Marine methane hydrate in sands has huge potential as an unconventional gas resource; however, no field test of their production potential had been conducted. Here, we report the world’s first offshore methane hydrate production test conducted at the eastern Nankai Trough and show key findings toward future commercial production. Geological analysis indicates that hydrate saturation reaches 80% and permeability in the presence of hydrate ranges from 0.01 to 10 mdarcies. Permeable (1–10 mdarcies) highly hydrate-saturated layers enable depressurization-induced gas production of approximately 20,000 Sm3/D with water of 200 m3/D. Numerical analysis reveals that the dissociation zone expands laterally 25 m at the front after 6 days. Gas rate is expected to increase with time, owing to the expansion of the dissociation zone. It is found that permeable highly hydrate-saturated layers increase the gas–water ratio of the production fluid. The identification of such layers is critically important to increase the en...

Product selectivity in plasmonic photocatalysis for carbon dioxide hydrogenation

Abstract: Photocatalysis has not found widespread industrial adoption, in spite of decades of active research, because the challenges associated with catalyst illumination and turnover outweigh the touted advantages of replacing heat with light. A demonstration that light can control product selectivity in complex chemical reactions could prove to be transformative. Here, we show how the recently demonstrated plasmonic behaviour of rhodium nanoparticles profoundly improves their already excellent catalytic properties by simultaneously reducing the activation energy and selectively producing a desired but kinetically unfavourable product for the important carbon dioxide hydrogenation reaction. Methane is almost exclusively produced when rhodium nanoparticles are mildly illuminated as hot electrons are injected into the anti-bonding orbital of a critical intermediate, while carbon monoxide and methane are equally produced without illumination. The reduced activation energy and super-linear dependence on light intensity cause the unheated photocatalytic methane production rate to exceed the thermocatalytic rate at 350 °C. Atmospheric CO2 can be transformed into valuable hydrocarbons by reaction with H2, but CO is the favoured kinetic product. Here, Liu and co-workers show that plasmonic rhodium nanoparticles not only reduce the activation energy for CO2hydrogenation, but also photo-selectively produce methane.

Homogeneous Functionalization of Methane

Abstract: One of the remaining “grand challenges” in chemistry is the development of a next generation, less expensive, cleaner process that can allow the vast reserves of methane from natural gas to augment or replace oil as the source of fuels and chemicals. Homogeneous (gas/liquid) systems that convert methane to functionalized products with emphasis on reports after 1995 are reviewed. Gas/solid, bioinorganic, biological, and reaction systems that do not specifically involve methane functionalization are excluded. The various reports are grouped under the main element involved in the direct reactions with methane. Central to the review is classification of the various reports into 12 categories based on both practical considerations and the mechanisms of the elementary reactions with methane. Practical considerations are based on whether or not the system reported can directly or indirectly utilize O2 as the only net coreactant based only on thermodynamic potentials. Mechanistic classifications are based on whet...

Designed oxygen carriers from macroporous LaFeO3 supported CeO2 for chemical-looping reforming of methane

Abstract: Chemical-looping reforming of methane (CLRM) offers an effective approach for coproducing syngas and pure hydrogen. In this work, CeO2 nano particles (2–3 nm) are well dispersed on the wall surface of three-dimensional ordered macroporous (3DOM) LaFeO3, obtaining a highly efficient oxygen carrier for the CLRM technology. The physical and chemical properties of the oxygen carriers were characterized by SEM, TEM, H2-TPR, XPS, XRD, CH4-TPR and CH4-TPD techniques. It is found that the presence of CeO2 on LaFeO3 results in the formation of Ce3+ and Fe2+ due to the CeO2-LaFeO3 interaction. The coexistence of Ce3+ and Fe2+ irons induces abundant oxygen vacancies on the mixed oxides, which strongly improves the reducibility, oxygen mobility and reactivity for methane oxidation. The presence of CeO2 also improves the resistance towards carbon deposition formation, and this allows the CeO2/LaFeO3 materials own high available oxygen storage capacity (available OSC, the maximum amount of oxygen consumed by methane reduction without the formation of carbon deposition). It is also noted that the agglomeration of CeO2 nano particles would reduce the reactivity of oxygen carriers. Among all the obtained samples, the 10% CeO2/LaFeO3 sample exhibits the highest yields of syngas (9.94 mmol g−1) and pure hydrogen (3.38 mmol g−1) without the formation of carbon deposition, which are much higher than that over the pure LaFeO3 sample (5.73 mmol g−1 for syngas yield and 2.00 mmol g−1 for hydrogen yield). In addition, the CeO2/LaFeO3 oxygen carrier also showed high stability during the successive CLRM testing either in the activity (yields of syngas and pure hydrogen) or structure (macroporous frameworks) aspect.

Direct Conversion of Methane to Methanol under Mild Conditions over Cu-Zeolites and beyond

Abstract: ConspectusIn the recent years methane has become increasingly abundant. However, transportation costs are high and methane recovered as side product is often flared rather than valorized. The chemical utilization of methane is highly challenging and currently mainly based on the cost-intensive production of synthesis gas and its conversion. Alternative routes have been discovered in academia, though high temperatures are mostly required. However, the direct conversion of methane to methanol is an exception. It can already be carried out at comparably low temperatures. It is challenging that methanol is more prone to oxidation than methane, which makes high selectivities at moderate conversions difficult to reach. Decades of research for the direct reaction of methane and oxygen did not yield a satisfactory solution for the direct partial oxidation toward methanol. When changing the oxidant from oxygen to hydrogen peroxide, high selectivities can be reached at rather low conversions, but the cost of hydrog...

Selective Activation of Methane on Single-Atom Catalyst of Rhodium Dispersed on Zirconia for Direct Conversion

Abstract: Direct methane conversion into value-added products has become increasingly important. Because of inertness of methane, cleaving the first C–H bond has been very difficult, requiring high reaction temperature on the heterogeneous catalysts. Once the first C–H bond becomes activated, the remaining C–H bonds are successively dissociated on the metal surface, hindering the direct methane conversion into chemicals. Here, a single-atom Rh catalyst dispersed on ZrO2 surface has been synthesized and used for selective activation of methane. The Rh single atomic nature was confirmed by extended X-ray fine structure analysis, electron microscopy images, and diffuse reflectance infrared Fourier transform spectroscopy. A model of the single-atom Rh/ZrO2 catalyst was constructed by density functional theory calculations, and it was shown that CH3 intermediates can be energetically stabilized on the single-atom catalyst. The direct conversion of methane was performed using H2O2 in the aqueous solution or using O2 in g...

Methane Oxidation to Methanol Catalyzed by Cu-Oxo Clusters Stabilized in NU-1000 Metal-Organic Framework.

Abstract: Copper oxide clusters synthesized via atomic layer deposition on the nodes of the metal–organic framework (MOF) NU-1000 are active for oxidation of methane to methanol under mild reaction conditions. Analysis of chemical reactivity, in situ X-ray absorption spectroscopy, and density functional theory calculations are used to determine structure/activity relations in the Cu-NU-1000 catalytic system. The Cu-loaded MOF contained Cu-oxo clusters of a few Cu atoms. The Cu was present under ambient conditions as a mixture of ∼15% Cu+ and ∼85% Cu2+. The oxidation of methane on Cu-NU-1000 was accompanied by the reduction of 9% of the Cu in the catalyst from Cu2+ to Cu+. The products, methanol, dimethyl ether, and CO2, were desorbed with the passage of 10% water/He at 135 °C, giving a carbon selectivity for methane to methanol of 45–60%. Cu oxo clusters stabilized in NU-1000 provide an active, first generation MOF-based, selective methane oxidation catalyst.

Catalytic molten metals for the direct conversion of methane to hydrogen and separable carbon

Abstract: Metals that are active catalysts for methane (Ni, Pt, Pd), when dissolved in inactive low–melting temperature metals (In, Ga, Sn, Pb), produce stable molten metal alloy catalysts for pyrolysis of methane into hydrogen and carbon. All solid catalysts previously used for this reaction have been deactivated by carbon deposition. In the molten alloy system, the insoluble carbon floats to the surface where it can be skimmed off. A 27% Ni–73% Bi alloy achieved 95% methane conversion at 1065°C in a 1.1-meter bubble column and produced pure hydrogen without CO 2 or other by-products. Calculations show that the active metals in the molten alloys are atomically dispersed and negatively charged. There is a correlation between the amount of charge on the atoms and their catalytic activity.

Low-temperature activation of methane on the IrO2(110) surface.

Abstract: Methane undergoes highly facile C–H bond cleavage on the stoichiometric IrO2(110) surface. From temperature-programmed reaction spectroscopy experiments, we found that methane molecularly adsorbed as a strongly bound σ complex on IrO2(110) and that a large fraction of the adsorbed complexes underwent C–H bond cleavage at temperatures as low as 150 kelvin (K). The initial dissociation probability of methane on IrO2(110) decreased from 80 to 20% with increasing surface temperature from 175 to 300 K. We estimate that the activation energy for methane C–H bond cleavage is 9.5 kilojoule per mole (kJ/mol) lower than the binding energy of the adsorbed precursor on IrO2(110), and equal to a value of ~28.5 kJ/mol. Low-temperature activation may avoid unwanted side reactions in the development of catalytic processes to selectively convert methane to value-added products.

Ambiguity in the causes for decadal trends in atmospheric methane and hydroxyl

Abstract: Methane is the second strongest anthropogenic greenhouse gas and its atmospheric burden has more than doubled since 1850. Methane concentrations stabilized in the early 2000s and began increasing again in 2007. Neither the stabilization nor the recent growth are well understood, as evidenced by multiple competing hypotheses in recent literature. Here we use a multispecies two-box model inversion to jointly constrain 36 y of methane sources and sinks, using ground-based measurements of methane, methyl chloroform, and the C13/C12 ratio in atmospheric methane (δ13CH4) from 1983 through 2015. We find that the problem, as currently formulated, is underdetermined and solutions obtained in previous work are strongly dependent on prior assumptions. Based on our analysis, the mathematically most likely explanation for the renewed growth in atmospheric methane, counterintuitively, involves a 25-Tg/y decrease in methane emissions from 2003 to 2016 that is offset by a 7% decrease in global mean hydroxyl (OH) concentrations, the primary sink for atmospheric methane, over the same period. However, we are still able to fit the observations if we assume that OH concentrations are time invariant (as much of the previous work has assumed) and we then find solutions that are largely consistent with other proposed hypotheses for the renewed growth of atmospheric methane since 2007. We conclude that the current surface observing system does not allow unambiguous attribution of the decadal trends in methane without robust constraints on OH variability, which currently rely purely on methyl chloroform data and its uncertain emissions estimates.

Uncoupling the size and support effects of Ni catalysts for dry reforming of methane

Abstract: The dry reforming of methane (DRM; CH 4 + CO 2 ↔ 2H 2 + 2CO) can be a good way to utilize greenhouse gases for the production of valuable syn-gas. Ni-based catalysts have been used for this reaction; however, the Ni size effect and support effect were highly coupled and therefore could not be observed separately. Here, a unique catalyst in which the Ni nanoparticle size and support can be varied independently was devised. Highly uniform Ni nanoparticles with sizes of 2.6, 5.2, 9.0, and 17.3 nm were tested for DRM at 800 °C without a significant change in the Ni size, and overlayers of various metal oxides, including SiO 2 , Al 2 O 3 , MgO, ZrO 2 , TiO 2 , were tested with the 5.2 nm of Ni nanoparticles. The dependence of the CH 4 or CO 2 turnover frequency on the Ni size and support was evaluated separately. The 2.6 nm Ni nanoparticles showed 4.1 times higher methane turnover frequency than those with a size of 17.3 nm. When various metal oxide overlayers were tested with the same 5.2 nm Ni, Al 2 O 3 exhibited 4.3 times higher methane turnover frequency than SiO 2 . The independent observation of the effects of the Ni nanoparticle size and support will provide valuable guidelines for designing effective methane dry reforming catalysts.

The ruminal microbiome associated with methane emissions from ruminant livestock.

Abstract: Methane emissions from ruminant livestock contribute significantly to the large environmental footprint of agriculture. The rumen is the principal source of methane, and certain features of the microbiome are associated with low/high methane phenotypes. Despite their primary role in methanogenesis, the abundance of archaea has only a weak correlation with methane emissions from individual animals. The composition of the archaeal community appears to have a stronger effect, with animals harbouring the Methanobrevibacter gottschalkii clade tending to be associated with greater methane emissions. Ciliate protozoa produce abundant H2, the main substrate for methanogenesis in the rumen, and their removal (defaunation) results in an average 11% lower methane emissions in vivo, but the results are not consistent. Different protozoal genera seem to result in greater methane emissions, though community types (A, AB, B and O) did not differ. Within the bacteria, three different ‘ruminotypes’ have been identified, two of which predispose animals to have lower methane emissions. The two low-methane ruminotypes are generally characterized by less abundant H2-producing bacteria. A lower abundance of Proteobacteria and differences in certain Bacteroidetes and anaerobic fungi seem to be associated with high methane emissions. Rumen anaerobic fungi produce abundant H2 and formate, and their abundance generally corresponds to the level of methane emissions. Thus, microbiome analysis is consistent with known pathways for H2 production and methanogenesis, but not yet in a predictive manner. The production and utilisation of formate by the ruminal microbiota is poorly understood and may be a source of variability between animals.

Ni/CeO2 based catalysts as oxygen vectors for the chemical looping dry reforming of methane for syngas production

Abstract: Chemical looping dry reforming of methane (CLDRM) is performed by exposing a Ni/CeO2 solid to CH4 and CO2 in a cyclic way. The solid acts as an oxygen vector producing syngas (CO + H2) during exposure to CH4, and is re-oxidized during exposure to CO2. Absence of CO2 during syngas production allows suppressing reverse water gas shift reaction and reaching high selectivity. Exposure to CO2 restores the oxygen capacity of the support and removes residual carbon formed at the surface, thus fully regenerating the catalyst. Solids were characterized by TPR, XRD, Raman scattering, and XPS. Results show that part of the Ni is reduced and remain in metallic state during the looping process. On the other hand, Ni2+ species in strong interaction with Ce cations are observed even after exposure to methane. Both Ni species play important roles on reactants activation and oxygen supply by the solid. Ni loading is a crucial parameter for controlling the reduction behavior of the support and therefore for CLDRM process optimization.

Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor

Abstract: Widespread methane release from thawing Arctic gas hydrates is a major concern, yet the processes, sources, and fluxes involved remain unconstrained We present geophysical data documenting a cluster of kilometer-wide craters and mounds from the Barents Sea floor associated with large-scale methane expulsion Combined with ice sheet/gas hydrate modeling, our results indicate that during glaciation, natural gas migrated from underlying hydrocarbon reservoirs and was sequestered extensively as subglacial gas hydrates Upon ice sheet retreat, methane from this hydrate reservoir concentrated in massive mounds before being abruptly released to form craters We propose that these processes were likely widespread across past glaciated petroleum provinces and that they also provide an analog for the potential future destabilization of subglacial gas hydrate reservoirs beneath contemporary ice sheets

Reduced biomass burning emissions reconcile conflicting estimates of the post-2006 atmospheric methane budget.

Abstract: Several viable but conflicting explanations have been proposed to explain the recent ~8 p.p.b. per year increase in atmospheric methane after 2006, equivalent to net emissions increase of ~25 Tg CH4 per year. A concurrent increase in atmospheric ethane implicates a fossil source; a concurrent decrease in the heavy isotope content of methane points toward a biogenic source, while other studies propose a decrease in the chemical sink (OH). Here we show that biomass burning emissions of methane decreased by 3.7 (±1.4) Tg CH4 per year from the 2001–2007 to the 2008–2014 time periods using satellite measurements of CO and CH4, nearly twice the decrease expected from prior estimates. After updating both the total and isotopic budgets for atmospheric methane with these revised biomass burning emissions (and assuming no change to the chemical sink), we find that fossil fuels contribute between 12–19 Tg CH4 per year to the recent atmospheric methane increase, thus reconciling the isotopic- and ethane-based results. The drivers of the increase in atmospheric methane since 2006 remain unclear. Here, the authors use satellite and in situ measurements of CO and CH4 to show that fossil fuels and biogenic sources contribute 12–19 Tg CH4per year and 12–16 Tg CH4per year respectively to the recent atmospheric methane increase.