More Like this

1. Hyperselective carbon membranes for precise high-temperature H₂ and CO₂ separation

   https://doi.org/10.1126/sciadv.adt7512  

   Iyer, Gaurav M; Ku, Ching-En; Zhang, Chen (June 2025, Science Advances)

   More than 90% of the world’s hydrogen (H₂) is produced from fossil fuel sources, which requires energy-intensive separation and purification to produce high-purity H₂fuel and to capture the carbon dioxide (CO₂) by-product. While membranes can decarbonize H₂/CO₂separation, their moderate H₂/CO₂selectivity requires secondary H₂purification by pressure swing adsorption. Here, we report hyperselective carbon molecular sieve hollow fiber membranes showing H₂/CO₂selectivity exceeding 7000 under mixture permeation at 150°C, which is almost 30 times higher than the most selective nonmetallic membrane reported in the literature. The membrane is able to maintain an ultrahigh H₂/CO₂selectivity over 1400 under mixture permeation at 400°C. Pore structure characterization suggests that highly refined ultramicropores are responsible for effectively discriminating the closely sized H₂and CO₂molecules in the hyperselective carbon molecular sieve membrane. Modeling shows that the unprecedented H₂/CO₂selectivity will potentially allow one-step enrichment of fuel-grade H₂from shifted syngas for decarbonized H₂production. 

   more » « less
2. Power and carbon monoxide co-production by a proton-conducting solid oxide fuel cell with La _0.6 Sr _0.2 Cr _0.85 Ni _0.15 O _3−δ for on-cell dry reforming of CH ₄ by CO ₂

   https://doi.org/10.1039/D0TA03458D  

   Wei, Tong; Qiu, Peng; Jia, Lichao; Tan, Yuan; Yang, Xin; Sun, Shichen; Chen, Fanglin; Li, Jian (May 2020, Journal of Materials Chemistry A)

   null (Ed.)

   To directly use a CO 2 –CH 4 gas mixture for power and CO co-production by proton-conducting solid oxide fuel cells (H-SOFCs), a layer of in situ reduced La 0.6 Sr 0.2 Cr 0.85 Ni 0.15 O 3−δ (LSCrN@Ni) is fabricated on a Ni–BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3−δ (BZCYYb) anode-supported H-SOFC (H-DASC) for on-cell CO 2 dry reforming of CH 4 (DRC). For demonstrating the effectiveness of LSCrN@Ni, a cell without adding the LSCrN@Ni catalyst (H-CASC) is also studied comparatively. Fueled with H 2 , both H-CASC and H-DASC show similar stable performance with a maximum power density ranging from 0.360 to 0.816 W cm −2 at temperatures between 550 and 700 °C. When CO 2 –CH 4 is used as the fuel, the performance and stability of H-CASC decreases considerably with a maximum power density of 0.287 W cm −2 at 700 °C and a sharp drop in cell voltage from the initial 0.49 to 0.10 V within 20 h at 0.6 A cm −2 . In contrast, H-DASC demonstrates a maximum power density of 0.605 W cm −2 and a stable cell voltage above 0.65 V for 65 h. This is attributed to highly efficient on-cell DRC by LSCrN@Ni. 

   more » « less
3. Analysis On How Certain Marine Phytoplankton Species Are Being Affected by Ocean Acidification On the U.S East Coast

   Zeno, J; Goes, J (December 2023, Proceedings American Geophysical Union)

   Goes, J (Ed.)

   Earth’s oceans serve as a large atmospheric reservoir where carbon dioxide is absorbed and stored. In modern years, fossil fuel emissions have caused a large influx of CO₂ into the atmosphere and thus it is being absorbed into the oceans causing ocean acidification. This phenomenon has vast negative impacts, especially on the most abundant organism in the ocean– phytoplankton. Using data from a cruise in 2018, a prominent pH gradient has been mapped along the East Coast of the U.S, with Northeastern waters being more acidic. It is the purpose of this research to investigate how certain phytoplankton species are responding to this pH gradient and changes in their nutrient supplies. Four different species of phytoplankton were chosen from the Long Island Sound, and are currently being tested in varying concentrations of CO₂ (280 ppm, 400 ppm, and 800 ppm) – to mimic the pre industrial, modern, and future CO₂ levels of the Atlantic ocean. With the preliminary results of this experiment, it’s evident that the Diatom taxa is performing best overall, and specifically well in the 280 ppm, because of their unique carbon concentrating mechanisms that allow them to outcompete other phytoplankton in low pCO₂ waters. Future research will include monitoring this ongoing CO₂ experiment as well as testing other species of phytoplankton. It’s imperative to understand how these phytoplankton will react to changes in their environments as harmful algal blooms are becoming more common with climate change. 

   more » « less
4. Atmospheric CO ₂ over the Past 66 Million Years from Marine Archives

   https://doi.org/10.1146/annurev-earth-082420-063026  

   Rae, James W.B.; Zhang, Yi Ge; Liu, Xiaoqing; Foster, Gavin L.; Stoll, Heather M.; Whiteford, Ross D.M. (May 2021, Annual Review of Earth and Planetary Sciences)

   null (Ed.)

   Throughout Earth's history, CO 2 is thought to have exerted a fundamental control on environmental change. Here we review and revise CO 2 reconstructions from boron isotopes in carbonates and carbon isotopes in organic matter over the Cenozoic—the past 66 million years. We find close coupling between CO 2 and climate throughout the Cenozoic, with peak CO 2 levels of ∼1,500 ppm in the Eocene greenhouse, decreasing to ∼500 ppm in the Miocene, and falling further into the ice age world of the Plio–Pleistocene. Around two-thirds of Cenozoic CO 2 drawdown is explained by an increase in the ratio of ocean alkalinity to dissolved inorganic carbon, likely linked to a change in the balance of weathering to outgassing, with the remaining one-third due to changing ocean temperature and major ion composition. Earth system climate sensitivity is explored and may vary between different time intervals. The Cenozoic CO 2 record highlights the truly geological scale of anthropogenic CO 2 change: Current CO 2 levels were last seen around 3 million years ago, and major cuts in emissions are required to prevent a return to the CO 2 levels of the Miocene or Eocene in the coming century. ▪  CO 2 reconstructions over the past 66 Myr from boron isotopes and alkenones are reviewed and re-evaluated. ▪  CO 2 estimates from the different proxies show close agreement, yielding a consistent picture of the evolution of the ocean-atmosphere CO 2 system over the Cenozoic. ▪  CO 2 and climate are coupled throughout the past 66 Myr, providing broad constraints on Earth system climate sensitivity. ▪  Twenty-first-century carbon emissions have the potential to return CO 2 to levels not seen since the much warmer climates of Earth's distant past. 

   more » « less
5. Moderate to Elevated Atmospheric CO ₂ During the Early Paleocene Recorded by Platanites Leaves of the San Juan Basin, New Mexico

   https://doi.org/10.1029/2021PA004408  

   Milligan, Joseph N.; Flynn, Andrew G.; Kowalczyk, Jennifer B.; Barclay, Richard S.; Geng, Jie; Royer, Dana L.; Peppe, Daniel J. (April 2022, Paleoceanography and Paleoclimatology)

   Abstract Throughout the Phanerozoic, estimated CO₂levels from CO₂proxies generally correlate well with independent estimates of temperature. However, some proxy estimates of atmospheric CO₂during the Late Cretaceous and early Paleocene are low (<400 ppm), seemingly at odds with elevated sea surface temperature. Here we evaluate early Paleocene CO₂by applying a leaf gas‐exchange model toPlatanitesleaves of four early Paleocene localities from the San Juan Basin, New Mexico (65.66–64.59 Ma). We first calibrate the model on two modernPlatanusspecies,Platanus occidentalisandP. × acerifolia, where we find the leaf gas‐exchange model accurately predicts present‐day CO₂, with a mean error rate between 5% and 14%. Applying the model to the early Paleocene, we find CO₂varies between ∼660 and 1,140 ppm. These estimates are consistent with more recent CO₂estimates from boron, leaf gas‐exchange, liverwort, and paleosol proxies that all suggest moderate to elevated levels of CO₂during the Late Cretaceous and early Paleocene. These levels of atmospheric CO₂are more in keeping with the elevated temperature during this period. 

   more » « less