Loss Of CO Research Articles

The importance of understanding (pre)catalyst activation in versatile C-H bond functionalisations catalysed by [Mn2(CO)10

Mn-catalysed reactions offer great potential in synthetic organic and organometallic chemistry and the success of Mn carbonyl complexes as (pre)catalysts hinges on their stabilisation by strong field ligands enabling Mn(i)-based, redox neutral, catalytic cycles. The mechanistic processes underpinning the activation of the ubiquitous Mn(0) (pre)catalyst [Mn2(CO)10] in C-H bond functionalisation reactions is now reported for the first time. By combining time-resolved infra-red (TRIR) spectroscopy on a ps-ms timescale and in operando studies using in situ infra-red spectroscopy, insight into the microscopic bond activation processes which lead to the catalytic activity of [Mn2(CO)10] has been gained. Using an exemplar system, based on the annulation between an imine, 1, and Ph2C2, 2, TRIR spectroscopy enabled the key intermediate [Mn2(CO)9(1)], formed by CO loss from [Mn2(CO)10], to be identified. In operando studies demonstrate that [Mn2(CO)9(1)] is also formed from [Mn2(CO)10] under the catalytic conditions and is converted into a mononuclear manganacycle, [Mn(CO)4(C^N)] (C^N = cyclometallated imine), a second molecule of 1 acts as the oxidant which is, in turn, reduced to an amine. As [Mn(CO)4(C^N)] complexes are catalytically competent, a direct route from [Mn2(CO)10] into the Mn(i) catalytic reaction coordinate has been determined. Critically, the mechanistic differences between [Mn2(CO)10] and Mn(i) (pre)catalysts have been delineated, informing future catalyst screening studies.

Infrared spectra and fragmentation dynamics of isotopologue-selective mixed-ligand complexes.

Isolated mixed-ligand complexes provide tractable model systems in which to study competitive and cooperative binding effects as well as controlled energy flow. Here, we report spectroscopic and isotopologue-selective infrared photofragmentation dynamics of mixed gas-phase Au(12/13CO)n(N2O)m+ complexes. The rich infrared action spectra, which are reproduced well using simulations of calculated lowest energy structures, clarify previous ambiguities in the assignment of vibrational bands, especially accidental coincidence of CO and N2O bands. The fragmentation dynamics exhibit the same unexpected behaviour as reported previously in which, once CO loss channels are energetically accessible, these dominate the fragmentation branching ratios, despite the much lower binding energy of N2O. We have investigated the dynamics computationally by considering anharmonic couplings between a relevant subset of normal modes involving both ligand stretch and intermolecular modes. Discrepancies between correlated and uncorrelated model fit to the ab initio potential energy curves are quantified using a Boltzmann sampled root mean squared deviation providing insight into efficiency of vibrational energy transfer between high frequency ligand stretches and the softer intermolecular modes which break during fragmentation.

Sulfur-tolerant mechanism in catalytic combustion of toluene over Co/5Mg-γ-Al2O3 catalyst: Dual functions of MgO

Using toluene catalytic combustion as a probe reaction, simulating quantitative sulfur poisoning by in situ thermal decomposition of ammonium sulfate solution, the study used MgO modified γ-Al2O3 to support cobalt-based catalyst, and the result displayed that the catalyst exhibited excellent sulfur poisoning resistance. The successful construction of MgO-Al2O3 heterogeneous interface weakened the interaction between Co and Al and reduced the production of inactive CoAl2O4. Besides that, it fixed sulfur species and formed MgSO4 to protect active components. The dual function of MgO have been proved by various characterization experiments. The modification of γ-Al2O3 by the appropriate amount of MgO could improve the catalytic activity of Co/γ-Al2O3. Meanwhile, T100 increased from 300 °C to 330 °C after 1.6 wt% sulfur poisoning and we concluded that the decrease in catalytic performance was not caused by the loss of active Co, but by the decrease of specific surface area and lattice oxygen activity.

Exploring the limits of current ventilation systems and the unexplored potential

This paper compares the current generation of ventilation systems: natural ventilation, exhaust ventilation, and balanced ventilation, and weighs them against an ideal benchmark case. To achieve this, a transparent, selfdeveloped evaluation framework is constructed. This assessment framework is used to calculate three different and distinct performance indicators, namely CO2, moisture, and energy losses. The performance indicators are used to show the weaknesses and strengths of the systems in terms of indoor air quality (IAQ) and energy consumption, which are used to introduce a novel concept in terms of air recycling to increase IAQ and reduce energy consumption.

Utilizing Direct Membrane Deposition to Improve the Performance of Forward-Bias Bipolar Membrane CO2 Electrolysers

The electrochemical conversion of CO2 to multi-carbon products (C2+), such as ethylene and ethanol, is an attractive technology towards achieving net zero carbon emission goals. Among the available configurations of CO2 electrolysers, those employing a bipolar membrane (BPM) in forward-bias mode (f-BPM) reduce CO2 loss to the anode – a problem commonly faced in traditional anion exchange membrane (AEM) electrolysers. Therefore, carbon efficiency (the percent of input CO2 that is converted to C2+ products) and system operational costs can be improved.In f-BPM electrolysers, (bi)carbonate ions move through the AEM then combine with protons moving through the cation exchange membrane (CEM) to regenerate CO2 and H2O at the AEM|CEM interface. Recent reports have implemented a porous AEM structure or an added AEM|CEM interface channel to aid the movement of CO2 from the AEM|CEM interface to the cathode and, thus, avoid blistering. Despite the advantage of f-BPM CO2 electrolysers, their performance is limited by the parasitic H2 evolution reaction (>20% Faradaic efficiency, or FE) and the low C2+ FE (<40%) at industrially relevant reaction rates (≥200 mA cm-2). We attribute this performance limitation to the unintended gaps between the used AEM and CEM. Inadequate contact between the AEM and CEM is anticipated to reduce the extent of local CO2 regeneration and promote unwanted proton crossover to the cathode; both phenomena could be contributing to the commonly observed FEs.In this report, we enhanced the contact between the AEM and CEM through the use of direct membrane deposition (DMD) over a Cu-based cathode. The DMD approach enabled modular control over the AEM and CEM thicknesses and structures, which improved ion and gas transport. Through electrochemical impedance spectroscopy, the DMD system was observed to improve the mass transport by >58% compared to a system that is similar to current f-BPM electrolysers (i.e., control system). The facilitated mass transport resulted in a reduction of the operating cell potential (by 0.84 V) and an enhancement of the C2+ FE to 65% (from 29% in the control system) at 300 mA cm-2. The flexibility of the DMD approach also enabled the fabrication of asymmetric BPMs, resulting in a record low H2 FE of 12% at 300 mA cm-2. We also demonstrated a 79% single-pass CO2 conversion (SPC) with 67% C2+ FE, resembling the highest simultaneous SPC and C2+ FE achievement at high current density (300 mA cm-2)among current f-BPM electrolysers. The DMD benefit was also applicable to other types of CO2 electrolysers, such as CO2-to-CO silver catalyst electrolysers, in which the CO FE was boosted to 90% (from 65% in the control system) at 90 mA cm-2. Figure 1

Harnessing the power of microbes for sustainable development: Climate change mitigation and sustainable food security

AbstractThe effects of releasing carbon from the terrestrial pool into the atmosphere have significant long‐term and short‐term implications that affect many parts of our globe. Agricultural fields might help to address these concerns and provide cost‐effective solutions, such as lowering carbon dioxide levels (CO2) in the atmosphere while raising carbon levels in the soil. In order to increase agricultural land's potential to absorb and store carbon, the proper selection of suitable microbial inoculants with the capability to sequester carbon into soils is critical. Soil quality and characteristics would improve as a result, and atmospheric carbon would therefore be reduced. Soil microbes have the potential to influence the level of organic matter, which has an impact on the soil's ecological system and characteristics. Soil microbes play a role in carbon sequestration in soils by regulating multiple and distinct pathways for CO2 inputs and losses, such as biochemical processes that could sequester CO2, the capacity to sediment carbonates, the rigid nature of their components and vegetative tissues, or the composition of complex substances that preserve carbon in the soil. Further research is needed to investigate if particular microbial strains that can sequester carbon will help enhance soil quality and prevent climate change.

Efficient and stable acidic CO2 electrolysis to formic acid by a reservoir structure design.

Electrochemical synthesis of valuable chemicals and feedstocks through carbon dioxide (CO2) reduction in acidic electrolytes can surmount the considerable CO2 loss in alkaline and neutral conditions. However, achieving high productivity, while operating steadily in acidic electrolytes, remains a big challenge owing to the severe competing hydrogen evolution reaction. Here, we show that vertically grown bismuth nanosheets on a gas-diffusion layer can create numerous cavities as electrolyte reservoirs, which confine in situ-generated hydroxide and potassium ions and limit inward proton diffusion, producing locally alkaline environments. Based on this design, we achieve formic acid Faradaic efficiency of 96.3% and partial current density of 471 mA cm-2 at pH 2. When operated in a slim continuous-flow electrolyzer, the system exhibits a full-cell formic acid energy efficiency of 40% and a single pass carbon efficiency of 79% and performs steadily over 50 h. We further demonstrate the production of pure formic acid aqueous solution with a concentration of 4.2 weight %.

Long-term summer warming reduces post-fire carbon dioxide losses in an arctic heath tundra

The frequency and extent of wildfires in the Arctic has been increasing due to climate change. However, there is a lack of understanding about long-term impacts of climate warming on post-fire carbon dioxide (CO2) exchange in arctic tundra ecosystems. To investigate this, we conducted an experimental low-intensity fire in combination with summer warming (using open top chambers) in a dry heath tundra ecosystem in West Greenland. We report here on the impact four and five years after the fire. We also examined immediate effects of soil heating to three temperature levels (35, 55 and 80 °C), as a simulation of heat transfer during a typical tundra fire. Fire increased soil organic phosphorus concentrations up to at least four years after the burning. The burned areas remained a net CO2 source five years after the fire, mainly due to the lower aboveground vegetation biomass and reduced gross ecosystem production (GEP). However, with four to five years of summer warming, the GEP, ecosystem respiration and soil respiration significantly increased, and burned areas turned into a net CO2 sink. Ex-situ soil heating to the temperature of 55 °C, reaching the heat load comparable with in-situ burning, had minor effects on soil GHG fluxes. This suggests that soil GHG activities are not immediately affected by heat transfer and associated soil temperature increases during a typical low-intensity wildfire in arctic dry tundra. Overall, our results reveal that in a future warmer climate, vegetation is likely to recover more quickly from fires, resulting in a reduction in post-fire CO2 losses.

A high accuracy reference facility for ongoing comparisons of CO2 in air standards

The design, performance characteristics and validation of a next generation reference facility for carbon dioxide (CO2) in air standards based on manometry is presented. Novel attributes of the facility include automated operation, avoidance of significant pressure corrections for measurements on extracted CO2, fully characterized trapping efficiencies, and reduced measurement uncertainty. Improvements in system performance have been achieved using specific materials, notably Silconert®-treated stainless-steel, providing increased mechanical stability whilst minimizing carbon dioxide adsorption on surfaces, and avoiding use of elastomer O-rings, which would lead to losses of CO2. Full automation of the cryogenic extraction process of CO2 from air has been achieved, avoiding any manual intervention within the temperature stabilized section of the facility, and allowed full characterization and correction for trapping efficiencies and trace water measurement. The facility has been validated across the CO2 in air amount fraction range of (380–800) µmol mol−1 using standards with values traceable to the reference value of the CCQM−K120 (2018) comparison. It was demonstrated to operate with a standard measurement uncertainty of 0.09 µmol mol−1 at 400 µmol mol−1. The automation allows five measurement results per day to be produced with a typical standard deviation of the mean at or below 0.02 µmol mol−1. The facility will be used as a stable reference in the future BIPM.QM−K2 ongoing comparison, to compare consistency of amount fraction values in different CO2 in air standards. The CO2 amount fraction in two ensembles of nine BIPM standards covering the same range will also be measured with the facility to provide their SI-traceable values, and further monitored on a longer time scale. Each ensemble will constitute a CO2 in air scale to be compared with other available scales such as WMO.CO2.X2019 through the BIPM.QM−K5 comparison.

The Emission of Volatile Components during Laboratory Vitrification When Using Fly Ash and Other Waste to Obtain Ceramic Coatings

For decades, a significant amount of research has been conducted on the vitrification of mixtures of all kinds of industrial wastes, especially fly ash, both from thermal power plants and municipal waste incinerators. Although the possibility of creating glass from all types of fly ash has been proven through such research, these studies barely focused on the emission of volatile components that takes place during vitrification processes at high temperatures. This is why, after identifying the types of volatilisation that can occur, we characterised the gasses that are emitted during the vitrification of some types of fly ash and other waste in a laboratory furnace. In order to do so, we analysed the Cl2 and SO2 gasses emitted using the DTA/TG/FTIR techniques, as well as the losses of H2O and CO2. The authors also measured the volatilizations directly from the mouth of the furnace using gas chromatography syringes and analysed the possible emission of dioxins. This study is the first analysis of volatile elements of this kind, after numerous vitrifications in recent decades which ignored the volatilisations that occur when using fly ashes. Although the various types of fly ash used generate emissions of Cl2 and SO2, their use as a by-product on an industrial level could be recommended if previous thermal and washing treatments are conducted. These would minimise the above emissions, enabling the use of said fly ash in the production of glasses for commercial frits, even if an efficient industrial-scale gas cleaning system would apply. Furthermore, an appropriate optimised design of its formulation would make it possible to structurally link some of these gaseous components to the glass structure. These types of results will make it possible to calculate the volatilization when vitrifying certain types of industrial waste on an industrial level, although these studies would require prior assessment in a pilot plant.

Techno-economic sensitivity assessment for supercritical CO2 extraction of lycopene from tomato processing waste

Natural lycopene is in demand by food and drug industries, and tomato processing waste (TPW) holds promise as a valuable source. Previous research investigated supercritical fluid extraction (SFE) from TPW in a techno-economic context, but lacks understanding of how technical and economic factors impact profitability. This study fills the gap by establishing a hierarchy of significance for factors affecting SFE profitability. The investigation encompasses various parameters such as static and dynamic extraction times, extractor volume, CO2 loss, project lifetime, interest rate, corporate tax rate, operator salary, cost of SFE equipment, and prices of CO2, electricity, and extract oil. The parameter boundaries are defined using well-sourced data from relevant literature. Our findings highlight that the SFE facility becomes profitable when the extractor capacity surpasses 42 L. The most influential factors on NPV include the price of the extract, the interest rate, the dynamic time of SFE, and the project lifetime.

Amine-functionalized disordered hierarchical porous silica derived from blast furnace slag with high adsorption capability and cyclic stability for CO2 adsorption

This study proposes a novel solution to the challenge of achieving high cycle stability in CO2 adsorbents prepared through impregnation with organic amines. Specifically, industrial waste blast furnace slag was used to prepare a support material called BHF, which possesses three pore structures: micropores, mesopores, and macropores. This unique structure facilitates high loading of organic amines and improves CO2 adsorption effectiveness. To counteract agglomeration effects caused by loading large amounts of organic amines, the morphology and skeleton of the carrier material were analyzed in detail. The results showed that the rough “hive” morphology, disordered cell-like skeleton structure and abundant pores of BHF allows for uniform dispersion of polyethyleneimine (PEHA), an organic amine, and provides advantageous transportation of CO2 molecules within the adsorbent. Based on the study of kinetics, activation energy, and isosteric heat of adsorption, the adsorption mechanism of 70PEHA-BHF was determined to be a chemical-physical binding adsorption. The adsorption-diffusion mechanism suggests that the rate-limiting step is film diffusion. Furthermore, the 70PEHA-BHF adsorbent achieves a balance between CO2 adsorption capacity and cycle stability. At 80 °C and 15 vol.% CO2, the CO2 adsorption capacity of 70PEHA-BHF is 6.27 mmol/g, with only a 1.43 % CO2 loss after 10 cycles of testing. It anticipates that this newly developed 70PEHA-BHF adsorbent will provide additional possibilities for the application of hierarchical porous materials in CO2 adsorption research.

Assessment of the Fermentative Performance of Traditional Fresh Moroccan Sourdoughs and Their Freeze-Dried Forms Using Online Monitoring Device: Panigraph

The fermentative activity of sourdoughs and their stabilities are some of the main concerns of professionals in food science. The aim of this study was to evaluate the fermenting capacity of three traditional fresh sourdoughs and their freeze-dried forms with different compositions prepared by housewives in three different regions of Morocco. A device equipped with several sensors was developed to monitor several parameters simultaneously and in real time (the pH, dough rise, loss of mass, CO2 and ethanol release). The results showed that the duration of dough fermentation was long, ranging from 594 to 1210 min, with the specific volume ranging from 0.9 to 3.35 cm3/g−1. A strong and positive correlation between dough rise and CO2 release was observed, while ethanol release did not contribute directly to dough rise. The fresh sourdough FS1 showed better fermentative performance than the others, while the freeze-dried sourdough FDS3 was also of interest for bread making. The system used to generate the graphical fingerprints enabled us to read the main fermentation parameters directly in the same graph, as well as to compare several sourdoughs at once and choose the one best suited to our needs.

Primary and Secondary Processes in the Ultraviolet Photodissociation of CpCo(CO)2 (Cyclopentadienylcobalt Dicarbonyl).

We investigated the photodissociation dynamics of CpCo(CO)2 (cyclopentadienylcobalt dicarbonyl) in metal-to-ligand charge transfer (MLCT) bands. By employing DFT calculations, the absorption band (210-240 nm) was characterized as a charge transfer from the Co center to the Cp (cyclopentadienyl, C5H5) ligand. Ion imaging was utilized to analyze the CO fragments and coordinatively unsaturated complexes (CpCoCO, CpCo, and CoC3H3) across the entire MLCT band. Measuring the production yields of individual unsaturated complexes as a function of photolysis wavelength by considering wavelength dependence indicated the involvement of several photochemical pathways: the first photodissociation and sequential dissociation of CpCo(CO)2, and the second photodissociation of unsaturated intermediates within the pulse duration of the photolysis laser. The recoil velocity shifts of CpCo and CoC3H3 were attributed to the onset of the sequential dissociation of CpCoCO. Evidence for the second photodissociation of CpCoCO was obtained through the matching of linear momenta between the CO(v = 0, 1) and CpCo fragments. The DFT calculations performed to determine the electronic structures and potential energy curves for photoinduced CO loss in CpCo(CO)2 and CpCoCO supported our interpretation of the experimental results. This study presents a practical approach to selectively detecting specific processes among the mixture of products and intermediates when photolyzing transition-metal carbonyls, as their concurrent generation is unavoidable in laser-based experiments.

Microenvironment Regulation Strategies Facilitating High-Efficiency CO2 Electrolysis in a Zero-Gap Bipolar Membrane Electrolyzer.

In alkaline and neutral zero-gap CO2 electrolyzers, the carbon utilization efficiency of the electrocatalytic CO2 reduction to CO is less than 50% because of inherently homogeneous reactions. Utilization of the bipolar membrane (BPM) electrolyzer can effectively suppress (bi)carbonate formation and parasitic CO2 losses; however, an excessive concentration of H+ in the catalyst layer (CL) significantly hinders the activity and selectivity for CO2 reduction. Here, we report a microenvironment regulation strategy that controls the CL thickness and ionomer content to regulate local CO2 transport and the local pH within the CL. We report 80% faradaic efficiency of CO at a current density of 400 mA/cm2 without the use of a buffering layer, exceeding that of state-of-the-art catalysts with a buffering layer. A carbon utilization efficiency of 63.6% at 400 mA/cm2 is also obtained. This study demonstrates the significance of regulating the microenvironment of the CL in a BPM system.

Favoring CO Intermediate Stabilization and Protonation by Crown Ether for CO2 Electromethanation in Acidic Media.

The large-scale deployment of CO2 electroreduction is hampered by deficient carbon utilization in neutral and alkaline electrolytes due to CO2 loss into (bi)carbonates. Switching to acidic media mitigates carbonation, but suffers from low product selectivity because of hydrogen evolution. Here we report a crown ether decoration strategy on a Cu catalyst to enhance carbon utilization and selectivity of CO2 methanation under acidic conditions. Macrocyclic 18-Crown-6 is found to enrich potassium cations near the Cu electrode surface, simultaneously enhancing the interfacial electric field to stabilize the *CO intermediate and accelerate water dissociation to boost *CO protonation. Remarkably, the mixture of 18-Crown-6 and Cu nanoparticles affords a CH4 Faradaic efficiency of 51.2 % and a single pass carbon efficiency of 43.0 % toward CO2 electroreduction in electrolyte with pH=2. This study provides a facile strategy to promote CH4 selectivity and carbon utilization by modifying Cu catalysts with supramolecules.

Favoring CO Intermediate Stabilization and Protonation by Crown Ether for CO2 Electromethanation in Acidic Media

AbstractThe large‐scale deployment of CO2 electroreduction is hampered by deficient carbon utilization in neutral and alkaline electrolytes due to CO2 loss into (bi)carbonates. Switching to acidic media mitigates carbonation, but suffers from low product selectivity because of hydrogen evolution. Here we report a crown ether decoration strategy on a Cu catalyst to enhance carbon utilization and selectivity of CO2 methanation under acidic conditions. Macrocyclic 18‐Crown‐6 is found to enrich potassium cations near the Cu electrode surface, simultaneously enhancing the interfacial electric field to stabilize the *CO intermediate and accelerate water dissociation to boost *CO protonation. Remarkably, the mixture of 18‐Crown‐6 and Cu nanoparticles affords a CH4 Faradaic efficiency of 51.2 % and a single pass carbon efficiency of 43.0 % toward CO2 electroreduction in electrolyte with pH=2. This study provides a facile strategy to promote CH4 selectivity and carbon utilization by modifying Cu catalysts with supramolecules.

Characterization of Gla proteoforms and non-Gla peptides of gamma carboxylated proteins: Application to quantification of prothrombin proteoforms in human plasma

Gamma (γ) carboxylation is an essential post-translational modification in vitamin K-dependent proteins (VKDPs), involved in maintaining critical biological homeostasis. Alterations in the abundance or activity of these proteins have pharmacological and pathological consequences. Importantly, low levels of fully γ-carboxylated clotting factors increase plasma des-γ-carboxy precursors resulting in little or no biological activity. Therefore, it is important to characterize the levels of γ-carboxylation that reflect the active state of these proteins. The conventional enzyme-linked immunosorbent assay for protein induced by vitamin K absence or antagonist II (PIVKA-II) quantification uses an antibody that is not applicable to distinguish different γ-carboxylation states. Liquid chromatography-mass spectrometry (LC-MS) approaches have been utilized to distinguish different γ-carboxylated proteoforms, however, these attempts were impeded by poor sensitivity due to spontaneous neutral loss of CO2 and simultaneous cleavage of the backbone bond in the collision cell. In this study, we utilized an alkaline mobile phase in combination with polarity switching (positive and negative ionization modes) to simultaneously identify and quantify γ-carboxylated VKDPs. The method was applied to compare Gla proteomics of prothrombin (FII) in 10 μL plasma samples of healthy control and warfarin-treated adults. We also identified surrogate non-Gla peptides for seven other VKDPs to quantify total (active plus inactive) protein levels. The total protein approach (TPA) was used to quantify absolute levels of the VKDPs in human plasma.

Photophysics of Fe-Fe hydrogenase mimic complexes for hydrogen evolution

The photophysical and electrochemical properties of the diiron hydrogenase mimic complex, [Fe2(dpet)(CO)6] (dpet = 1,2-diphenylethene-1,2-dithiol) have been studied using a combination of spectroscopic and electrochemical techniques including cyclic voltammetry, infrared spectroelectrochemistry (IR-SEC), ultrafast transient absorption (TA) spectroscopy and time-resolved infrared spectroscopy (TRIR), with the data interpretation aided by density functional theory (DFT). The complex is a viable catalyst for electrochemical hydrogen evolution, as shown by its electrochemical reversibility and significant increase in the catalytic current upon addition of trifluoroacetic acid (TFA). IR-SEC was used to identify the first and second reduction products, where formation of a bridging μ-CO species was observed. The ultrafast spectroscopy data show that CO loss is only a minor excited state relaxation pathway, unlike other previously reported [FeFe] catalysts, in agreement with steady-state photolysis. The excited state lifetime obtained for this complex (135 ps in DCM and 237 ps in MeCN) is insufficient for [Fe2(dpet)(CO)6] to function as a photocatalyst on its own. However, the photostability of the complex opens up an opportunity for its future use in conjunction with a photosensitiser in photochemical hydrogen evolution.

The Southern Ocean Carbon Cycle 1985–2018: Mean, Seasonal Cycle, Trends, and Storage

AbstractWe assess the Southern Ocean CO2 uptake (1985–2018) using data sets gathered in the REgional Carbon Cycle Assessment and Processes Project Phase 2. The Southern Ocean acted as a sink for CO2 with close agreement between simulation results from global ocean biogeochemistry models (GOBMs, 0.75 ± 0.28 PgC yr−1) and pCO2‐observation‐based products (0.73 ± 0.07 PgC yr−1). This sink is only half that reported by RECCAP1 for the same region and timeframe. The present‐day net uptake is to first order a response to rising atmospheric CO2, driving large amounts of anthropogenic CO2 (Cant) into the ocean, thereby overcompensating the loss of natural CO2 to the atmosphere. An apparent knowledge gap is the increase of the sink since 2000, with pCO2‐products suggesting a growth that is more than twice as strong and uncertain as that of GOBMs (0.26 ± 0.06 and 0.11 ± 0.03 Pg C yr−1 decade−1, respectively). This is despite nearly identical pCO2 trends in GOBMs and pCO2‐products when both products are compared only at the locations where pCO2 was measured. Seasonal analyses revealed agreement in driving processes in winter with uncertainty in the magnitude of outgassing, whereas discrepancies are more fundamental in summer, when GOBMs exhibit difficulties in simulating the effects of the non‐thermal processes of biology and mixing/circulation. Ocean interior accumulation of Cant points to an underestimate of Cant uptake and storage in GOBMs. Future work needs to link surface fluxes and interior ocean transport, build long overdue systematic observation networks and push toward better process understanding of drivers of the carbon cycle.