Green Carbon最新文献

Since the Fischer-Tropsch reaction was discovered by Otto Roelen in 1938, transition metal-catalyzed carbonylation reactions come in as one of the most important methods for preparing carbonyl-containing and carbon chain-increased compounds. As a result, the field of carbonylation research has received considerable attention over the past decades and continues to increase. With the continuous development of carbonylation and the in-depth study of the mechanism, more mechanistic details and variations have been revealed, which provide more possibilities for organic synthesis. Recently, copper catalysis has been introduced to the carbonylative functionalization of alkenes, thus enabling the rapid assembly of functionalized carbonyl compounds from simple starting materials. In this Account, we summarize the new findings in the Cu-catalyzed borocarbonylation of alkenes based on the generation and transformation of α-oxy carbene intermediates. We believe that the results presented in this Account will further inspire the design of new carbonylation reactions.

Conventional O₂ gasification for low-rank biomass/sludge conversion is prone to high CO₂ concentrations in the syngas because of its high O content and low calorific value. This study establishes a synergistic oxidation-reforming reaction route for the conversion of low-rank carbon-containing resources into high-quality syngas. The efficient oxidation-reforming reaction is based on the bifunctional catalyst NiO–Fe₂O₃/Al₂O₃, which includes Fe₂O₃ oxidation sites and NiO reforming sites. Hydrogen temperature-programmed reduction, together with X-ray diffraction and X-ray photoelectron spectroscopy experiments, demonstrated that the two functional active sites have strong interactions with the support, leading to efficient cooperation between the oxidation reaction and reforming reaction with regards to both the reaction sequence and C/H/O element balance. Syngas produced from biomass/sludge based on oxidation-reforming reactions has an extremely low CO₂ concentration of approximately 3%, and the valid gas (CO, H₂) concentration exceeds 95%. The valid gas yield of walnut shell reached 1452.9 mL/g, the total gas yield was 1507.2 mL/g, and the H₂/CO ratio was 1.02, which are all very close to the theoretical maximum values of 1553.1 mL/g and 1.01, respectively, demonstrating that the inherent CO₂/H₂O along with CH₄/tar species were efficiently converted to H₂ and CO through oxidation-reforming reactions. During a 60-cycle test, NiO-Fe₂O₃/Al₂O₃ exhibited good redox stability.

The electrochemical CO₂ reduction reaction (ECO₂RR) to formate is perceived as a technoeconomic pathway for transforming renewable electricity into fuels. However, the indeterminate mechanism underlying structural self-reconstruction obstructs the strategic design of a high-performance In catalyst for the ECO₂RR. In this study, we chose InOOH as the model catalyst to illustrate the dynamic structure of In-based catalysts during reconstruction in the ECO₂RR. The findings of the current study indicate that the in situ electrochemical reconstruction of crystalline InOOH results in the creation of crystalline In clusters/InOOH, followed by In/InOOH heterostructures, and finally, metallic In over time. The efficiencies of the different phases conformed to the sequence: In clusters/InOOH > In/InOOH heterostructures > metallic In. This progression leads to a continuous drop in maximum current density and Faradaic efficiency from 29.6 mA/cm² and 87% to 6.3 mA/cm² and 75%, respectively with time extending to 7200 s, at –1.0 V relative to the reversible hydrogen electrode. Our in situ characterization and theoretical studies highlighted the crucial role of the In-cluster/InOOH interface in CO₂ activation and conversion.

Biobutanol is an advanced biofuel that can be produced from excess lignocellulose via acetone-butanol-ethanol (ABE) fermentation. Although significant technological progress has been made in this field, attempts at large-scale lignocellulosic ABE production remain scarce. In this study, 1 m³ scale ABE fermentation was investigated using high inhibitor tolerance Clostridium acetobutylicum ABE-P1201 and steam-exploded corn stover hydrolysate (SECSH). Before expanding the fermentation scale, the detoxification process for SECSH was simplified by process engineering. Results revealed that appropriate pH management during the fed-batch cultivation could largely decrease the inhibition of the toxic components in undetoxified SECSH to the solventogenesis phase of the ABE-P1201 strains, avoiding “acid crash”. Therefore, after naturalizing the pH by Ca(OH)₂, the undetoxified SECSH, without removal of the solid components, reached 17.68 ± 1.30 g/L of ABE production with 0.34 ± 0.01 g/g of yield in 1 L scale bioreactor. Based on this strategy, the fermentation scale gradually expanded from laboratory-scale apparatus to pilot-scale bioreactors. Finally, 17.05 ± 1.20 g/L of ABE titer and 0.32 ± 0.01 g/g of ABE yield were realized in 1 m³ bioreactor, corresponding to approximately 145 kg of ABE production from 1 t of dry corn stover. The pilot-scale ABE fermentation demonstrated excellent stability during repeated operations. This study provided a simplified ABE fermentation strategy and verified the feasibility of the pilot process, providing tremendous significance and a solid foundation for the future industrialization of second-generation ABE plants.

Solid-state electrolytes (SSEs) are a solution to safety issues related to flammable organic electrolytes for Li batteries. Insufficient contact between the anode and SSE results in high interface resistance, thus causing the batteries to exhibit high charging and discharging overpotentials. Recently, we reduced the overpotential of Li stripping and plating by introducing a high proportion of dual-conductive phases into a composite anode. The current study investigates the interface resistance and stability of a composite electrode modified with Zn and a lower proportion of dual-conductive phases. Zn-cation-adsorbed Prussian blue is synthesized as an intermediate component for a Zn-modified composite electrode (Li-FeZnNC). The Li-FeZnNC symmetric cell presents a lower interface resistance and overpotential compared with Li-FeNC (without Zn modification) and Li-symmetric cells. The Li-FeZnNC symmetric cell shows high electrochemical stability during Li stripping and plating at different current densities and high stability for 200 h. Full batteries with a Li-FeZnNC composite anode, garnet-type SSE, and LiFePO₄ cathode show low charging and discharging overpotentials, a capacity of 152 mAh g⁻¹, and high stability for 200 cycles.

The bioconversion of lignocellulose has attracted global attention, due to the significant potential of agricultural and forestry wastes as renewable zero-carbon resources and the urgent need for substituting fossil carbon. The cellulosome system is a multi-enzyme complex produced by anaerobic bacteria, which comprises cellulases, hemicellulases, and associated enzymatic and non-enzymatic components that promote biomass conversion. To enhance their efficiency in degrading recalcitrant lignocellulosic matrices, cellulosomes have been employed to construct biocatalysts for lignocellulose bioconversion, such as consolidated bioprocessing and consolidated bio-saccharification. Hemicelluloses, the second most abundant polysaccharides in plant cell walls, hold valuable application potential but can also induce inhibitory effects on cellulose hydrolysis, thus highlighting the indispensable roles of hemicellulases within the cellulosome complex. This review evaluated current research on cellulosomal hemicellulases, comparing their types, abundance, and regulation, primarily focusing on eight known cellulosome-producing species of different origins. We also reviewed their growth conditions, their hemicellulose-degrading capabilities, and the inhibitory effects of hemicellulose on cellulosome-based lignocellulose saccharification. Finally, we proposed strategies for targeted enhancement of hemicellulase in cellulosomes to improve lignocellulose bioconversion in future studies.

Global plastics production is expected to exceed 400 million tons and reach 600 million tons by 2060. Their synthesis currently accounts for approximately 3% of global greenhouse gas emissions. Approximately 60% of all polymers are produced for single-use. Examples include shopping bags, packaging materials, mulch films, and soluble polymers for cosmetics and other purposes. Currently, only a portion of single-use plastic is recycled or disposed of in incinerators or landfills. An estimated 20% is not disposed of properly and pollutes the global environment, especially the oceans. In response to these challenges, the United Nations, European Union, and many nation-states are developing regulatory frameworks that encourage the chemical industry to produce plastics with a smaller environmental footprint and often support this through research funding. Possible solutions include: (1) the use of green energy, green hydrogen, bio-based feedstocks, or CO₂ in synthesis; (2) the reuse or recycling of plastics through conversion or pyrolysis; and (3) the production of biodegradable polymers. The German chemical industry contributes approximately one-third of polymer production in the EU. It is embedded in the EU regulatory and research landscape and anchored in the European Green Deal, which aims for carbon neutrality by 2050. In this paper, we describe how BASF and Evonik, two leading German chemical companies with strong but different polymer portfolios, respond to the call for greener polymers and how technologies are being developed to make polyurethanes, a particularly important and difficult-to-recycle family of elastomers and duromers, renewable and circular. Reducing the environmental footprint of plastics requires not only innovative materials but also proper governance, regulatory and collection systems, and public willingness to cooperate. In an international comparison of these competencies, expressed by the "polymer management index" (PMI), Germany achieved a top position.

Zeolites are characterized by their microporous, crystalline structures with a four-connected framework with variable compositions, predominantly aluminosilicates. They are extensively utilized as adsorbents, catalysts, and ion exchangers across domestic and industrial sectors. With the ongoing energy transition from fossil fuels to renewable sources and the pursuit of environmentally sustainable development, zeolites are increasingly being explored beyond their traditional application fields. They are investigated for their adsorption and catalytic capabilities in the protection and restoration of air, water, and soil quality, as well as in the environmentally friendly “green” production of chemicals. This review article details these novel and potential applications of zeolites, emphasizing the unique properties that render them suitable for each specific use case and discussing how these properties can be fine-tuned through material selection or tailored synthesis methods.

Developing efficient CO₂ utilization technologies can alleviate the urgent pressure on energy and the environment. Moreover, these technologies are crucial for achieving the goal of net zero emissions. Microalgae are photoautotrophic microorganisms that are the main sources of primary productivity in the biosphere. Cyanobacteria, the only prokaryotic microalgae, have also been considered as promising chassis for photosynthetic biosynthesis, directly converting solar energy and CO₂ into various bio-based products. This technological route is called photosynthetic biomanufacturing, and is advantageous to simultaneous carbon fixation and clean production. This review focuses on development mode, application and suggests trends related to the further development of photosynthetic biomanufacturing. With regard to the link between photosynthetic CO₂ fixation and the production of desired metabolites, we summarized and compared three widely adopted strategies. “Screening to find”, screening a large number of high-quality cyanobacterial resources and analyzing their intracellular metabolites are of significance for screening novel cyanobacterial species with high-value chemicals and properties of industrial relevance. “Engineering to modify”, the emergence and application of synthetic biological tools and metabolic engineering strategies have enhanced the ability to modify different cyanobacterial species to reshape more carbon to flow toward synthetic tailored chemicals. “Stressing to activate”, through special culture conditions and strategies, combined with omics analysis techniques, silent metabolic pathways and functional modules are activated to induce the accumulation of high-value chemicals. This review provides valid and updated information to facilitate the development of photosynthetic biosynthesis route with carbon fixation and clean production, providing specific feasible solutions for net zero emissions.

The effects of the metal ratio of NiCu catalysts on the low-temperature hydrodeoxygenation (HDO) of anisole were assessed on a neutral SiO₂ and an acidic γ-Al₂O₃ support. The activity of SiO₂-supported catalysts increases with the Ni content in the NiCu phase, related to Ni’s hydrogenation capacity. In contrast, on a γ-Al₂O₃ support, the activity decreases with the Ni content. Overall, Al₂O₃-supported catalysts, exhibiting a smaller NiCu alloy particle size, are more active than SiO₂-supported ones. In terms of selectivity, SiO₂-supported catalysts mainly hydrogenate anisole to methoxycyclohexane, while, particularly at higher conversions, γ-Al₂O₃-supported catalysts are able to further convert methoxycyclohexane to cyclohexane, demonstrating the importance of acid sites for low-temperature HDO. The Ni/Cu ratio also steers the selectivity, but not the catalyst stability. Deactivation phenomena are only support dependent: while on SiO₂-supported catalysts, active site sintering occurs, attributed to weak stabilization of metal particles by the support, acid catalyzed coking is the main cause of deactivation on the γ-Al₂O₃-supported catalysts.