Transformation Of Carbon Dioxide Research Articles

Efficient ultra-low voltage electrolysis of CO2 coupling with hydrazine oxidation degradation

Transforming carbon dioxide (CO2) into valuable fuels or chemicals through electrolysis represents a promising approach to reduce the carbon footprint. Conventional CO2 electrolysis yet faces a challenge in low energy efficiency due to the energy-intensive oxygen evolution reaction (OER) occurring at the anode. In this study, we present an advanced CO2 electrolysis system that pairs cathodic CO2 reduction with anodic degradation of hydrazine oxidation reaction (HzOR), enabling efficient CO2 electrolysis at an ultra-low voltage. To achieve this objective, two precious-metal-free electrocatalysts have been designed and fabricated. Specifically, a nickel single-atom catalyst anchored on porous carbon nanofibers has been developed for cathodic CO2-to-CO conversion, while a flower-like Ni2Fe2N catalyst grown in-situ on nickel foam has been developed for anodic HzOR. We demonstrate high efficiency of CO production (FECO > 80%) at 100 mA cm−2 with an applied voltage of only 0.45 V by simultaneously degrading hydrazine in a flow cell.

Covalent Organic Frameworks as Promising Platforms for Efficient Electrochemical Reduction of Carbon Dioxide: A Review

In current research, achieving carbon neutrality has become a primary focus through the utilization of various conversion technologies that transform carbon dioxide (CO2) into valuable chemicals or fuels. Covalent organic frameworks (COFs), as emerging crystalline organic polymers, offer distinct advantages in CO2 conversion compared to other materials. These advantages include controllable nanoscale pores, predefined functional units, editable framework structures, and rich conjugated systems. The unique characteristics of COFs make them highly promising electrocatalysts for CO2 conversion. This review provides a comprehensive overview of pioneering works and recent research on the utilization of COF‐based materials as electrocatalysts for electrochemical CO2 reduction reaction. This review offers a comprehensive analysis of the design principles for various reactive sites, skeleton structures, pore functionalities, 3D frameworks, morphologies, and composite materials of COFs, aiming to enhance electrocatalysis. Finally, this review presents some recommendations for material design, reaction mechanisms, and theoretical computations to enhance the understanding of reaction mechanisms further and facilitate the design of high‐performance COF‐based electrocatalysts.

Improved Electrochemical Reduction of CO2 to Syngas with Highly Exfoliated Ti3C2Tx MXene-Gold Composite

Transforming carbon dioxide (CO2) into valuable chemicals via electroreduction presents a sustainable and viable approach to mitigate the excess CO2 in the atmosphere. This report provides fresh insights into the...

Donor-acceptor activation of Carbon Dioxide.

The activation and functionalization of carbon dioxide entails great interest related to its abundance, low toxicity and associated environmental problems. However, the inertness of CO2 has posed a challenge towards its efficient conversion to added-value products. In this review we discuss one of the strategies that have been widely used to capture and activate carbon dioxide, namely the use of donor-acceptor interactions by partnering a Lewis acidic and a Lewis basic fragment. This type of CO2 activation resembles that found in metalloenzymes, whose outstanding performance in catalytically transforming carbon dioxide encourages further bioinspired research. We have divided this review into three general sections based on the nature of the active sites: metal-free examples (mainly formed by frustrated Lewis pairs), main group-transition metal combinations, and transition metal heterobimetallic complexes. Overall, we discuss one hundred compounds that cooperatively activate carbon dioxide by donor-acceptor interactions, revealing a wide range of structural motifs.

α-Tocopherol application as a countermeasure to UV-B stress in bread wheat (Triticum aestivum L.).

The source of energy for all photoautotrophic organisms is light, which is absorbed by photosynthetic processes and used to transform carbon dioxide and H2O into organic molecules. The majority of UV-B light (280 to 320 nm) is absorbed by stratospheric ozone layer, although some of it does reach at the Earth's surface. Because of the sedentary lifestyle of plants, this form of abiotic stress is unavoidable and can induce growth and even cell death. Ten-day-old calli generated from mature Kirik wheat embryos were subjected to UV-B radiation for 0, 2, 4, and 6 h to examine the function of exogenous α-tocopherol, a lipophilic antioxidant, in wheat tolerance to UV-B radiation stress. The calli were then moved to a callus medium containing α-tocopherol (0, 50, and 100 mg/l) and cultivated there for 20 days after being subjected to UV-B stress. For plant regeneration, embryogenic calli were put on a medium for plant regeneration after 30 days. The findings of this investigation demonstrated that an increase in UV-B exposure period resulted in a substantial drop in the relative growth rate of callus, the rate of embryogenic callus, the rate of responding embryogenic callus, and the number of plants in each explant. On the other hand, with the application of α-tocopherol, all these parameters improved, and the best result was observed in the application of 100 mg/l of α-tocopherol in terms of plant regeneration under UV-B stress.

The Metabolism of Reactive Oxygen Species and Their Effects on Lipid Biosynthesis of Microalgae

Microalgae have outstanding abilities to transform carbon dioxide (CO2) into useful lipids, which makes them extremely promising as renewable sources for manufacturing beneficial compounds. However, during this process, reactive oxygen species (ROS) can be inevitably formed via electron transfers in basal metabolisms. While the excessive accumulation of ROS can have negative effects, it has been supported that proper accumulation of ROS is essential to these organisms. Recent studies have shown that ROS increases are closely related to total lipid in microalgae under stress conditions. However, the exact mechanism behind this phenomenon remains largely unknown. Therefore, this paper aims to introduce the production and elimination of ROS in microalgae. The roles of ROS in three different signaling pathways for lipid biosynthesis are then reviewed: receptor proteins and phosphatases, as well as redox-sensitive transcription factors. Moreover, the strategies and applications of ROS-induced lipid biosynthesis in microalgae are summarized. Finally, future perspectives in this emerging field are also mentioned, appealing to more researchers to further explore the relative mechanisms. This may contribute to improving lipid accumulation in microalgae.

Zeaxanthin epoxidase is involved in the carotenoid biosynthesis and light-dependent growth of the marine alga Nannochloropsis oceanica

BackgroundThe marine alga Nannochloropsis oceanica, an emerging model belonging to Heterokont, is considered as a promising light-driven eukaryotic chassis for transforming carbon dioxide to various compounds including carotenoids. Nevertheless, the carotenogenic genes and their roles in the alga remain less understood and to be further explored.ResultsHere, two phylogenetically distant zeaxanthin epoxidase (ZEP) genes from N. oceanica (NoZEP1 and NoZEP2) were functionally characterized. Subcellular localization experiment demonstrated that both NoZEP1 and NoZEP2 reside in the chloroplast yet with differential distribution patterns. Overexpression of NoZEP1 or NoZEP2 led to increases of violaxanthin and its downstream carotenoids at the expense of zeaxanthin in N. oceanica, with the extent of changes mediated by NoZEP1 overexpression being greater as compared to NoZEP2 overexpression. Suppression of NoZEP1 or NoZEP2, on the other hand, caused decreases of violaxanthin and its downstream carotenoids as well as increases of zeaxanthin; similarly, the extent of changes mediated by NoZEP1 suppression was larger than that by NoZEP2 suppression. Interestingly, chlorophyll a dropped following violaxanthin decrease in a well-correlated manner in response to NoZEP suppression. The thylakoid membrane lipids including monogalactosyldiacylglycerol also correlated with the violaxanthin decreases. Accordingly, NoZEP1 suppression resulted in more attenuated algal growth than NoZEP2 suppression did under either normal light or high light stage.ConclusionsThe results together support that both NoZEP1 and NoZEP2, localized in the chloroplast, have overlapping roles in epoxidating zeaxanthin to violaxanthin for the light-dependent growth, yet with NoZEP1 being more functional than NoZEP2 in N. oceanica. Our study provides implications into the understanding of carotenoid biosynthesis and future manipulation of N. oceanica for carotenoid production.

Review on CeO2-Based Photocatalysts for Photocatalytic Reduction of CO2: Progresses and Perspectives

A promising approach is to transform carbon dioxide (CO2) into renewable, high value-added products with minimal environmental impact and maximum efficiency. Many problems, including energy shortages and environmental degradation, are caused by high CO2 levels, but this can help. Photocatalytic reduction methods are a promising technology for solving these problems. Cerium dioxide (CeO2) is one of the most important rare earth oxides, and cerium dioxide-based photocatalysts have gained a lot of attention in recent years due to their distinctive features, such as their tunable electronic structures and their excellent photocatalytic performances. However, the wide energy band of cerium oxide limits its utilization of light. This review provides various strategies for the modification of cerium oxide, encompassing external atom doping, heterostructure fabrication, defect fabrication, and crystal plane modulation, to improve the catalytic performance of CeO2. The fundamentals of the conversion of CeO2-based photocatalysts into high value-added products are also summarized. Finally, the challenges and prospects of CeO2-based catalysts for photocatalytic reduction of CO2 are presented.

The CO2 Reduction Reaction Mechanism on Silicene Nanoflakes. A Theoretical Perspective

AbstractFrom density functional theory calculations, we elucidated the reaction mechanism of CO2 reduction on silicene nanoflakes. According to the results, silicene monoflakes present a notable catalytic activity for the hydrogenation of CO2. The most probable energetically favorable reaction pathway is formic acid and formaldehyde production, with energy barriers ranging between 16 and 24.1 kcal/mol. At the same time, transforming carbon dioxide to methanol, carbon monoxide, and methane requires higher activation energies. This theoretical perspective provides significant insights into silicene‐based materials and their potential applications as CO2 conversion to fuel and value‐added chemicals.

Heterogenous Preparations of Solution-Processable Cobalt Phthalocyanines for Carbon Dioxide Reduction Electrocatalysis

The development and implementation of technology that can capture and transform carbon dioxide (CO2) is of ongoing interest. To that end, the integration of molecular electrocatalysts into devices is appealing because of the desirable features of molecules, such as the ability to modify active sites. Here, we explore how the identity of the aliphatic group in 1,4,8,11,15,18,22,25-octaalkoxyphthalocyanine cobalt(II) affects the catalytic behavior for heterogeneous CO2 reduction electrocatalysis. The alkyl R-groups correspond to n-butoxy, sec-butoxy, and 2-ethylhexoxy. All of the catalysts are soluble in organic solvents and are readily solution-processed. However, the larger 2-ethylhexoxy group showed solution aggregation behavior at concentrations ≥1 mM, and it was, in general, an inferior catalyst. The other two catalysts show comparable maximum currents, but the octa sec-butoxy-bearing catalyst showed larger CO2 reduction rate constants based on foot-of-the-wave analyses. This behavior is hypothesized to be due to the ability of the sec-butoxy groups to eliminate the ability of the alkoxy oxygen to block Co Sites via ligation. CO2 reduction activity is rationalized based on solid-state structures. Cobalt(II) phthalocyanine and its derivatives are known to be good CO2 reduction catalysts, but the results from this work suggest that straightforward incorporation of bulky groups can improve the processability and per site activity by discouraging aggregation.

Transforming carbon dioxide and carbon monoxide into value-added products: boracarboxylation and boracarbonylation

This review surveys the current state-of-the-art of catalytic difunctionalization of unsaturated substrates with easily accessible feedstocks CO2/CO and heteroelement boron for the synthesis of fine chemicals and medicinally important molecules.

Elaborate tree-like Cu-Ag clusters from green electrodeposition for efficiently electrocatalyzing CO2 conversion into syngas.

The electrocatalytic carbon dioxide reduction (CO2RR) is one of the emerging technologies that can effectively transform carbon dioxide (CO2) into valuable products. Electrocatalysts deriving from green synthesis methods will significantly help to establish a new green carbon cycle. Herein, a green electrodeposition method without additional reducing agents was used to synthesize Cu-Ag bimetallic catalysts, and it is shown that the combination of Cu and Ag obviously affects the morphology of the Cu-Ag catalysts, resulting in the formation of elaborate tree-like Cu-Ag clusters. An as-deposited Cu-Ag/carbon fiber (Cu-Ag/CF) catalyst exhibits high activity, selectivity and stability toward the CO2RR; in particular, the elaborate dendritic Cu-Ag/CF can efficiently reduce CO2 to syngas with high selectivity (Faradaic efficiency (FE) > 95%) at a low onset potential (-0.5 V). This work provides a rational strategy to overcome the significantly different reaction capacities during the reduction of Ag+ and Cu2+, leading to the formation of a controlled morphology of Cu-Ag, which is favourable for the design and development of highly efficient Cu or Ag catalysts via green methods for electrocatalyzing the CO2RR.

Dual-metal sites CuInS2/g-C3N4Z-scheme heterojunction with efficient photocatalytic CO2 reduction selectivity

The application of solar energy to transform carbon dioxide into energy-rich products is one of the sustainable ways to alleviate energy scarcity and environmental crisis. However, the low efficiency of solar light and the high recombination of photogenerated electron-hole pairs limit the industrial value of photocatalytic technology in terms of applications. Here, we report a high-performance photocatalyst based on g-C3N4, which was compounded and modified utilizing CuInS2. The photocatalytic performance is enhanced by constructing Z-scheme heterojunction for efficient separation and transfer of photogenerated carriers to meet the practical application requirements. CuInS2/g-C3N4 has the best photocatalytic CO yield of 246.75 μmol/g/h and CO selectivity of more than 93%. The role of dual-metal sites in the catalytic system is also explored by DFT calculations. The results not only provide a new perspective for the design of efficient CO2 photoreduction photocatalysts, but also provide a proven method for enhancing the performance of photocatalysts.

Detection of Carbon Use Efficiency Extremes and Analysis of Their Forming Climatic Conditions on a Global Scale Using a Remote Sensing-Based Model

Carbon use efficiency (CUE) represents the proficiency of plants in transforming carbon dioxide (CO2) into carbon stock in terrestrial ecosystems. CUE extremes represent ecosystems’ extreme proficiency in carbon transformation. Studying CUE extremes and their forming climate conditions is critical for enhancing ecosystem carbon storage. However, the study of CUE extremes and their forming climate conditions on the global scale is still lacking. In this study, we used the results from the daily Boreal Ecosystem Productivity Simulator (BEPS) model to detect the positive and negative CUE extremes and analyze their forming climatic conditions on a global scale. We found grasslands have the largest potential in changing global CUE, with the contribution being approximately 32.4% to positive extremes and 30.2% to negative extremes. Spring in the Northern Hemisphere (MAM) contributed the most (30.5%) to positive CUE extremes, and summer (JJA) contributed the most (29.7%) to negative CUE extremes. The probabilities of gross primary production (GPP) extremes resulted in CUE extremes (>25.0%) being larger than autotrophic respiration (Ra), indicating CUE extremes were mainly controlled by GPP rather than Ra extremes. Positive temperature anomalies (0~1.0 °C) often accompanied negative CUE extreme events, and positive CUE extreme events attended negative temperature anomalies (−1.0~0 °C). Moreover, positive (0~20.0 mm) and negative precipitation (−20.0~0 mm) anomalies often accompanied positive and negative CUE extremes, respectively. These results suggest that cooler and wetter climate conditions could be beneficial to enhance carbon absorptions of terrestrial ecosystems. The study provides new knowledge on proficiency in carbon transformation by terrestrial ecosystems.

Thermodynamic approach to foresee experimental CO2 reduction to organic compounds

Anaerobic gas fermentation is a promising approach to transform carbon dioxide (CO2) into chemical building blocks. However, the main operational conditions to enhance the process and its selectivity are still unknown. The main objective of this study was to trigger chain elongation from a joint perspective of thermodynamic and experimental assessment. Thermodynamics revealed that acetic acid formation was the most spontaneous reaction, followed by n-caproic and n-butyric acids, while the doorway for alcohols production was bounded by the selected conditions. Best parameters combinations were applied in three 0.12 L fermenters. Experimentally, n-caproic acid formation was boosted at pH 7, 37 °C, Acetate:Ethanol mass ratio of 1:3 and low H2 partial pressure. Though these conditions did not match with those required to produce their main substrates, the unification of both perspectives yielded the highest n-caproic acid concentration (>11 g L−1) so far from simple substrates, accounting for 77 % of the total products.

Inside Cover: Drastic Events and Gradual Change Define the Structure of an Active Copper‐Zinc‐Alumina Catalyst for Methanol Synthesis (Angew. Chem. Int. Ed. 15/2022)

Copper and zinc oxide are a dream team in transforming carbon dioxide and carbon monoxide together with hydrogen into the valuable base chemical methanol. Inspired by the cover art of the music masterpiece “Wish you were here” by Pink Floyd, the picture featuring the Research Article (e202200301) by Jeroen A. van Bokhoven and co-workers highlights the fundamental collaboration of the copper and zinc oxide phase in methanol catalysts for a sustainable future.

Uncovering the reaction mechanism behind CoO as active phase for CO2 hydrogenation

Transforming carbon dioxide into valuable chemicals and fuels, is a promising tool for environmental and industrial purposes. Here, we present catalysts comprising of cobalt (oxide) nanoparticles stabilized on various support oxides for hydrocarbon production from carbon dioxide. We demonstrate that the activity and selectivity can be tuned by selection of the support oxide and cobalt oxidation state. Modulated excitation (ME) diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) reveals that cobalt oxide catalysts follows the hydrogen-assisted pathway, whereas metallic cobalt catalysts mainly follows the direct dissociation pathway. Contrary to the commonly considered metallic active phase of cobalt-based catalysts, cobalt oxide on titania support is the most active catalyst in this study and produces 11% C2+ hydrocarbons. The C2+ selectivity increases to 39% (yielding 104 mmol h−1 gcat−1 C2+ hydrocarbons) upon co-feeding CO and CO2 at a ratio of 1:2 at 250 °C and 20 bar, thus outperforming the majority of typical cobalt-based catalysts.

Direct conversion of CO2 to solid carbon by Ga-based liquid metals

We present a simple alternative pathway to transform carbon dioxide to perpetually stored solid carbon.

Riddled with holes: Understanding air space formation in plant leaves.

Plants use energy from sunlight to transform carbon dioxide from the air into complex organic molecules, ultimately producing much of the food we eat. To make this complex chemistry more efficient, plant leaves are intricately constructed in 3 dimensions: They are flat to maximise light capture and contain extensive internal air spaces to increase gas exchange for photosynthesis. Many years of work has built up an understanding of how leaves form flat blades, but the molecular mechanisms that control air space formation are poorly understood. Here, I review our current understanding of air space formation and outline how recent advances can be harnessed to answer key questions and take the field forward. Increasing our understanding of plant air spaces will not only allow us to understand a fundamental aspect of plant development, but also unlock the potential to engineer the internal structure of crops to make them more efficient at photosynthesis with lower water requirements and more resilient in the face of a changing environment.

LanzaTech, Twelve to make polypropylene

Two start-ups, LanzaTech and Twelve, are partnering to transform carbon dioxide into polypropylene. Twelve uses the electrochemical reduction of CO 2 to make molecules such as carbon monoxide, methane, and ethylene. LanzaTech has technology to produce ethanol by fermenting CO from industrial waste streams. If all the world’s polypropylene were converted to the new process, 700 million metric tons per year of carbon emissions would be eliminated, Twelve says. Impact Squared Group has given the companies a $200,000 grant for their work.