Green Carbon最新文献

Cyanobacteria are promising oxygenic phototrophs for the production of various compounds. For their (photo)biotechnological exploitation, molecular tools are required, such as, for the introduction and expression of heterologous genes, or the modulation of enzyme activities or entire pathways. Concepts and strategies for the development of photosynthetic biomanufacturing technologies based on cyanobacteria have been extensively reviewed, as well as certain specialized aspects of their genetic manipulation. However, options for metabolic engineering of specific cyanobacterial cells are still less developed than those for other bacteria of biotechnological relevance. In addition to the standard genetic toolbox for “classical” metabolic engineering, we emphasize certain aspects, including recently developed vector systems for the extrachromosomal maintenance of genes and approaches based on clustered regularly interspaced short palindromic repeats (CRISPR) interference. We highlight the development of custom molecular tools for specific strains or products, discuss the emerging use of small regulatory proteins that appear promising for advanced metabolic engineering approaches to promote specific product formation, and provide an overview of suitable online resources. Furthermore, we discuss the current trends in this field and indicate their potential, such as using suitable product sensors that enable systematic screening, and optimization approaches.

Previously, the once-through CO₂ chemical absorption process by biogas slurry was experimentally verified to offer the unique advantages like low energy consumption, cost-effectiveness, and feasibility of CO₂ fixation in plants. However, this technology also faces some challenges and limitations, including a low CO₂ absorption rate and performance. To improve the effectiveness and reliability of this innovative carbon capture, utilization, and storage (CCUS) technology, this study proposes a novel method to enhance the CO₂ absorption performance without affecting agricultural applications of CO₂ by mixing biogas slurry with biomass ash as the green CO₂ absorbent. The results indicate that when the solid-liquid mass ratio of biomass ash to biogas slurry is 5:10, the CO₂ loading of the biomass ash and biogas slurry mixture (BA-BS) reaches 936.7 ± 59.1 mmol/kg. Furthermore, the pH of the BA-BS remains stable at 6.9, meeting the rhizosphere pH requirements for plant cultivation. The CO₂ absorption of the BA-BS liquid phase, referred to as improved biogas slurry (IBS), reaches its maximum at 230.4 ± 3.5 mmol/L, which is 126.8% higher than that of the unimproved biogas slurry. The nitrogen content in the BA-BS solid phase, calling improved biomass ash (IBA), also reaches its maximum at 4.24 ± 0.74 mg/g, thereby expanding the agricultural utilization of biomass ash. The most reasonable and effective way of utilizing CO₂-rich mixed biogas slurry and biomass ash involves use IBA as the base fertilizer for tomato cultivation, supplemented later with IBS to promote growth. This optimal application allows for substantial utilization of CO₂, introduced into the tomato cultivation environment by IBA and IBS. The carbon fixation of a single tomato has improved by 108.2%. This study thus provides a feasible solution for high-value negative carbonization of biogas slurry and biomass ash.

The rational design of Fe–N–C catalysts that possess easily accessible active sites and favorable mass transfer, which are usually determined by the structure of catalyst supports, is crucial for the oxygen reduction reaction (ORR). In this study, an oleic acid-assisted soft-templating approach is developed to synthesize size-controlled nitrogen-doped carbon nanoparticles (ranging from 130 nm to 60 nm and 35 nm, respectively) that feature spiral mesopores on their surface (SMCs). Next, atomically dispersed Fe–N_x sites are fabricated on the size-tunable SMCs (Fe₁/SMC-x, where x represents the SMC size) and the size-dependent activity toward ORR is investigated. It is found that the catalytic performance of Fe₁/SMCs is significantly influenced by the size of SMCs, where the Fe₁/SMC-60 catalyst shows the highest ORR activity with a half-wave potential of 0.90 V vs. RHE in KOH electrolyte, indicating that the gas-liquid-solid three-phase interface on the Fe₁/SMC-60 enhances the accessibility of Fe–N_x sites. In addition, when using Fe₁/SMC-60 as the cathode catalyst in aqueous zinc-air batteries (ZABs), it delivers a higher open-circuit voltage (1.514 V), a greater power density (223 mW cm⁻²), and a larger specific capacity/energy than Pt/C-based counterparts. These results further highlight the potential of Fe₁/SMC-60 for practical energy devices associated with ORR and the importance of size-controlled synthesis of SMCs.

Employing biodegradable plastics is one of the choices to solve white pollution issues. Polybutylene succinate (PBS), as a biodegradable plastic with good stability and heat resistance, is produced by polymerization of succinic acid and butylene glycol. However, inadequate supply of the direct upstream material succinic acid restricts the development of this industry. In this work, we provide a carbonylative strategy to construct succinic acid derivatives from carbon monoxide (CO), ethylene and alcohols. The reaction catalyzed by palladium catalyst under oxidative conditions.

The excessive consumption of fossil fuels increases carbon dioxide (CO₂) emissions, and the consequent greenhouse effect resulting from higher levels of this gas in the atmosphere has a significant impact on the environment and climate. This has necessitated the development of environmentally friendly and efficient methods for CO₂ conversion. The carbon dioxide electroreduction reaction (CO₂RR), which is driven by electricity generated by renewable energy sources (e.g., wind and solar) to convert CO₂ into value-added fuels or chemicals, is regarded as a promising prospective path toward carbon cycling. Among the various products, formate, with its relatively simple preparation process, has broad application prospects, and can be used as fuel, hydrogen storage material, and raw material for downstream chemicals. Sn-based oxide electrocatalysts have the advantages of being inexpensive and nontoxic. In addition, these catalysts offer high product selectivity and are regarded as promising catalysts for the electrochemical reduction of CO₂ to formate. In this review, we first clarify the reaction mechanisms and factors that influence the reduction of CO₂ to formate, and then provide some examples of technologies that could be used to study the evolution of catalysts during the reaction. In particular, we focus on traditional Sn-based oxides (SnO₂) and novel Sn-based perovskite oxides that have been developed for use in the field of CO₂RR in recent years by considering their synthesis, catalytic performance, optimization strategies, and intrinsic principles. Finally, the current challenges and opportunities for Sn-based oxide electrocatalysts are discussed. The perspectives and latest trends presented in this review are expected to inspire researchers to contribute more efforts toward comprehensively optimizing the performance of the CO₂RR to produce formate.

Recently, significant research has been conducted on the conversion of carbon dioxide (CO₂) into value-added chemicals. With the decreasing cost of clean electricity, electrochemical methods have emerged as potential approaches for converting and fixing CO₂. Organic electrochemical synthesis is a promising method for utilizing CO₂ because it transforms CO₂ into higher-value chemicals. This review introduces the research aspects of CO₂ conversion and the mechanisms of CO₂ organic electrocarboxylation reactions. Recent progress in electrocarboxylation with CO₂ is discussed, considering organic substrates and cathode types under different reaction mechanisms. Finally, the challenges and prospects in this field are highlighted with the aim of further promoting the fundamental understanding of CO₂ organic electrocarboxylation.

Porous metal-based carbon nanocomposites, with a monolithic shape, were prepared by a one-pot synthesis from dissolved cellulose and metallic salts using a simple, cheap, and environmentally friendly route. Their potential performances as electrochemical capacitors were tested with three metal precursors (M = Cu, Mn, and Fe) with two loadings and in an asymmetric cell for the Fe-based carbon material. Interestingly, here soluble metal precursors were not deposited on a hard cellulose template but mixed in a precooled concentrated NaOH solution where cellulose was previously dissolved, allowing for a good dispersion of the metallic species. After a freezing step where concomitant cellulose regeneration and pore ice-templating phenomena took place, followed by a carbonization step, the mixture led to a porous carbon monolith embedding well-dispersed metal-based nanoparticles having a diameter below 20 nm and present as metallic, oxide, or carbide phase(s) according to the element M. These materials were characterized by different physicochemical techniques and electrochemical tests. Their performances as supercapacitors are discussed in light of the specific behaviour of the metal-based phase and its influence on the carbon matrix properties such as mesopore formation and carbon graphitization. An asymmetric energy storage cell assembled with a Fe-based carbon electrode against a carbon xerogel electrode derived from a phenolic resin shows specific energy and power of 18.3 Wh kg⁻¹ at 5 mA cm⁻² and 1.6 kW kg⁻¹ at 25 mA cm⁻², respectively.

Indoor heating results in high energy consumption and severe atmospheric pollution. Although the development of solar air heaters provides a sustainable route for indoor thermal comfort, such heaters still face challenges in terms of adequate heat exchange and filtering of atmospheric pollutants. Inspired by solar-driven interfacial evaporation, we propose a multifunctional carbon nanotube-based photothermal membrane for efficient cold air heating and purification via ventilation. Carbon nanotubes endow the membrane with high light absorption and thermal conversion capabilities, thereby sufficiently heating the approaching cold air. With the hierarchical structure formed by phase inversion, the thin upper skin of the composite membrane intercepts micropollutants via the size-sieving effect, whereas the finger-like pores and interpenetrating macrovoids inside the membrane ensure that the heated clear air passes through quickly. A proof-of-principle experiment indicated a cold airflow of 1 L/min across the membrane, yielding a temperature increase of ca. 37 °C as well as a PM 2.5 rejection always higher than 93%. Further antibacterial experiments demonstrated that the membrane effectively removed airborne bacteria. This multifunctional carbon nanotube-based photothermal membrane with specific microstructures not only improves the indoor living quality but also provides a sustainable development scheme to coordinate the relationship among energy utilization, building heating, and air purification.

Plastics are integral to numerous significant social advancements. Nonetheless, their contribution to environmental pollution and climate crises cannot be disregarded, as their negative impact on the environment increases with incremental production capacity and demand. Concerted global action is urgently required to promote the green recycle of plastics to prevent their accumulation in the environment and mitigate carbon emissions. This review aims to reveal the paths of green development for polyester plastics, incorporating the trends of the green revolution in mature commercial polyester plastics, newly emerging biodegradable polyester plastics, and future polyester plastics. A critical discussion was conducted on the current and potential future research areas from multiple perspectives, including raw materials, processes, and recycling, to propel us into a future marked by sustainability.