• Energy Research
• 2025-2025close
• Open Access close
• Closed Access close
• Open Source close
• natural sciences close

Scenarios to stabilize global climate and meet international climate agreements require rapid reductions in human carbon dioxide (CO2) emissions, often augmented by substantial carbon dioxide removal (CDR) from the atmosphere. While some ocean-based removal techniques show potential promise as part of a broader CDR and decarbonization portfolio, no marine approach is ready yet for deployment at scale because of gaps in both scientific and engineering knowledge. Marine CDR spans a wide range of biotic and abiotic methods, with both common and technique-specific limitations. Further targeted research is needed on CDR efficacy, permanence, and additionality as well as on robust validation methods—measurement, monitoring, reporting, and verification—that are essential to demonstrate the safe removal and long-term storage of CO2. Engineering studies are needed on constraints including scalability, costs, resource inputs, energy demands, and technical readiness. Research on possible co-benefits, ocean acidification effects, environmental and social impacts, and governance is also required.

Scenarios to stabilize global climate and meet international climate agreements require rapid reductions in human carbon dioxide (CO2) emissions, often augmented by substantial carbon dioxide removal (CDR) from the atmosphere. While some ocean-based removal techniques show potential promise as part of a broader CDR and decarbonization portfolio, no marine approach is ready yet for deployment at scale because of gaps in both scientific and engineering knowledge. Marine CDR spans a wide range of biotic and abiotic methods, with both common and technique-specific limitations. Further targeted research is needed on CDR efficacy, permanence, and additionality as well as on robust validation methods—measurement, monitoring, reporting, and verification—that are essential to demonstrate the safe removal and long-term storage of CO2. Engineering studies are needed on constraints including scalability, costs, resource inputs, energy demands, and technical readiness. Research on possible co-benefits, ocean acidification effects, environmental and social impacts, and governance is also required.

The regulation of catalyst activity and selectivity using a reducible support for the industrially relevant hydrogenation of 1,3-butadiene to more valuable butene products was achieved. Supported palladium and nickel–palladium catalysts on ceria were prepared and characterized with hydrogen temperature programmed reduction (H2-TPR), hydrogen temperature programmed desorption (H2-TPD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HR-TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), temperature programmed oxidation (TPO), energy dispersive spectroscopy (EDS), and N2 adsorption–desorption to examine their chemical and physical properties. Pathways guiding the reaction were determined using the density functional theory (DFT). H2-TPR confirmed that palladium oxide was reduced, and nickel oxide species strongly interacted with the CeO2 support. The Ce3+ concentration determined by XPS showed that all catalysts surface contained the Ce reduced state. The catalysts showed a similar BET surface area, with 4Pd–Ce presenting the lowest value due to particle aggregation, which was confirmed from the EDS mapping analysis. Butadiene conversion consistently increased with temperature (40 °C–120 °C) until full conversion was reached on all the Pd catalysts while the maximum conversion on the 4Ni-Ce catalyst was 88 % at 120 °C. Product distribution revealed that 4 % Pd content directed the products toward butane when 40 °C was exceeded. Constructed mechanisms by DFT calculations featured low reaction barriers for the involved surface hydrogenation steps, and thus, they accounted for the observed low temperature of the surface hydrogenation activity. Selective formation of 1-butene partially stemmed from its relatively weak binding to Ni sites in reference to Pd sites. The mapped-out mechanisms entailed a higher reaction barrier for the formation of 2-butene, in agreement with the experimental observation pertinent to its formation at higher temperatures when compared with that of 1-butene.

The regulation of catalyst activity and selectivity using a reducible support for the industrially relevant hydrogenation of 1,3-butadiene to more valuable butene products was achieved. Supported palladium and nickel–palladium catalysts on ceria were prepared and characterized with hydrogen temperature programmed reduction (H2-TPR), hydrogen temperature programmed desorption (H2-TPD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HR-TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), temperature programmed oxidation (TPO), energy dispersive spectroscopy (EDS), and N2 adsorption–desorption to examine their chemical and physical properties. Pathways guiding the reaction were determined using the density functional theory (DFT). H2-TPR confirmed that palladium oxide was reduced, and nickel oxide species strongly interacted with the CeO2 support. The Ce3+ concentration determined by XPS showed that all catalysts surface contained the Ce reduced state. The catalysts showed a similar BET surface area, with 4Pd–Ce presenting the lowest value due to particle aggregation, which was confirmed from the EDS mapping analysis. Butadiene conversion consistently increased with temperature (40 °C–120 °C) until full conversion was reached on all the Pd catalysts while the maximum conversion on the 4Ni-Ce catalyst was 88 % at 120 °C. Product distribution revealed that 4 % Pd content directed the products toward butane when 40 °C was exceeded. Constructed mechanisms by DFT calculations featured low reaction barriers for the involved surface hydrogenation steps, and thus, they accounted for the observed low temperature of the surface hydrogenation activity. Selective formation of 1-butene partially stemmed from its relatively weak binding to Ni sites in reference to Pd sites. The mapped-out mechanisms entailed a higher reaction barrier for the formation of 2-butene, in agreement with the experimental observation pertinent to its formation at higher temperatures when compared with that of 1-butene.

Abstract Geopolitical tensions and conflicts can disrupt energy markets, threatening international energy supply security and imposing financial stress on energy-intensive industries reliant on imported fossil fuels. Exploring the challenges and opportunities associated with supply diversification is crucial for understanding the potential for hard-to-abate industry decarbonization under the risk of future energy price shocks. In this context, we investigate the role of green hydrogen as a viable and sustainable alternative to natural gas applications in iron and steel manufacturing. We first quantify how the integration of green hydrogen into the existing infrastructure can complement stringent climate action ambitions in reducing CO2 emissions over the next five decades. We find that green hydrogen acts as a transitional technology, enabling a gradual shift towards electrification of heat supply while bridging the gap until low-carbon steel technologies become commercially feasible. Furthermore, we assess the benefits of timely green hydrogen investments in mitigating the economic repercussions of unforeseen natural gas price surges. Overall, this study underscores the potential of green hydrogen in decarbonizing the iron and steel industry while promoting energy independence, but it also highlights its contingency on sufficiently ambitious climate policies and adequate technological advancements.

Abstract Geopolitical tensions and conflicts can disrupt energy markets, threatening international energy supply security and imposing financial stress on energy-intensive industries reliant on imported fossil fuels. Exploring the challenges and opportunities associated with supply diversification is crucial for understanding the potential for hard-to-abate industry decarbonization under the risk of future energy price shocks. In this context, we investigate the role of green hydrogen as a viable and sustainable alternative to natural gas applications in iron and steel manufacturing. We first quantify how the integration of green hydrogen into the existing infrastructure can complement stringent climate action ambitions in reducing CO2 emissions over the next five decades. We find that green hydrogen acts as a transitional technology, enabling a gradual shift towards electrification of heat supply while bridging the gap until low-carbon steel technologies become commercially feasible. Furthermore, we assess the benefits of timely green hydrogen investments in mitigating the economic repercussions of unforeseen natural gas price surges. Overall, this study underscores the potential of green hydrogen in decarbonizing the iron and steel industry while promoting energy independence, but it also highlights its contingency on sufficiently ambitious climate policies and adequate technological advancements.

Oyster reef loss represents one of the most dramatic declines of a foundation species worldwide. Oysters provide valuable ecosystem services (ES), including habitat provisioning, water filtration, and shoreline protection. Since the 1990s, a global community of science and practice has organized around oyster restoration with the goal of restoring these valuable services. We highlight ES-based approaches throughout the restoration process, consider applications of emerging technologies, and review knowledge gaps about the life histories and ES provisioning of underrepresented species. Climate change will increasingly affect oyster populations, and we assess how restoration practices can adapt to these changes. Considering ES throughout the restoration process supports adaptive management. For a rapidly growing restoration practice, we highlight the importance of early community engagement, long-term monitoring, and adapting actions to local conditions to achieve desired outcomes.

Oyster reef loss represents one of the most dramatic declines of a foundation species worldwide. Oysters provide valuable ecosystem services (ES), including habitat provisioning, water filtration, and shoreline protection. Since the 1990s, a global community of science and practice has organized around oyster restoration with the goal of restoring these valuable services. We highlight ES-based approaches throughout the restoration process, consider applications of emerging technologies, and review knowledge gaps about the life histories and ES provisioning of underrepresented species. Climate change will increasingly affect oyster populations, and we assess how restoration practices can adapt to these changes. Considering ES throughout the restoration process supports adaptive management. For a rapidly growing restoration practice, we highlight the importance of early community engagement, long-term monitoring, and adapting actions to local conditions to achieve desired outcomes.

Globally, energy demands are massive, and environmental issues are rising against our sustainability. To maximize the use of renewable energy sources, development of efficient energy storage systems is mandatory. Lithium-ion batteries (LIBs) play an indispensable role in powering portable devices and electric vehicles, due to their high specific capacity and long cycle life. Manganese oxide (Mn3O4) is an environmentally friendly anode active material with high theoretical specific capacity of 936 mAh g−1 for applications in Li-ion cells.In the present work, Mn3O4-functionalized carbon nanotubes (FCNT) nanocomposite, coated on carbon cloth (CC) current collector and termed as Mn3O4-FCNT @CC, is used as the anode material. Li-ion coin cells based on this nanocomposite anode show discharge capacity of 1371mAhg−1 and charge capacity of 1141mAhg−1 at current density of 100 mA g−1 with initial Coulombic efficiency of 83%. After 70 cycles, the charge-discharge capacities of the cells are 953mAhg−1 and 958mAhg−1, respectively, with capacity retention of 91% at current rate of 100 mA g−1. These cells are found to deliver reversible charge capacity of 575mAhg−1 after 100 cycles at 1C (∼1 A g−1) and offer prospects of stable operation at high current rates.