Carbon Recycling Through CO2-Conversion for Stepping Toward a Cyclic-C Economy. A Perspective

The conversion of CO2 into added value chemicals, materials and fuels is a case of transition from the linear to the cyclic-C economy, a necessary change for stopping the putative negative effect of CO2 on climate and the environment. Several strategies can be implemented for CO2 conversion and their potential and timeframe is discussed in this perspective paper. The overall amount of avoided CO2 is evaluated in the short-, medium-, and long-term. The distinct contribution of Catalysis, Solar Chemistry and integrated Chemocatalysis-Biosystems is discussed

Biotechnology to develop innovative syntheses using CO2

We present an overview of possible biotechnological applications for using carbon dioxide for the synthesis of chemicals. These approaches are very appealing as they contribute to the implementation of new synthetic methodologies that reduce waste and make a better use of carbon and energy. Several synthetic approaches will be considered including both the incorporation of the whole COO moiety or its reduction to other C1 molecules. Each option will be discussed making a comparison between the natural and artificial process in order to highlight the possibility to learn from Nature and develop useful mimetic or enzymatic systems

Perspectives in the use of carbon dioxide

The mitigation of carbon dioxide is one of the scientific and technological challenges of the 2000s. Among the technologies that are under assessment, the recovery of carbon dioxide from power plants or industrial flue gases plays a strategic role. Recovered carbon dioxide can be either disposed in natural fields or used. The availability of large amounts of carbon dioxide may open new routes to its utilisation in biological, chemical and innovative technological processes. In this paper, the potential of carbon dioxide utilisation in the short-, medium-term is reviewed

Do Bio-Ethanol and Synthetic Ethanol Produced from Air-Captured CO2 Have the Same Degree of “Greenness” and Relevance to “Fossil C”?

This paper discusses the epochal change in the reputation of carbon dioxide, which is now considered as a raw material alternative to fossil C for the synthesis of chemicals, materials and fuels, as opposed to a waste material that must be confined underground. In particular, its use as renewable C is compared to biomass. In this paper, a specific point is discussed: is ethanol (or any fuel) produced via the catalytic conversion of atmospheric CO2 different from the relevant biomass-sourced product(s)? The answer to this question is very important because it ultimately determines whether or not fuels derived from atmospheric CO2 (either e-fuels or solar fuels) have the right to be subsidized in the same way that biofuels are. Conclusions are drawn demonstrating that ethanol derived from atmospheric CO2 deserves the same benefits as bio-ethanol, with the additional advantage that its synthesis can be less pollutant than its production via the fermentation of sugars. The same concept can be applied to any fuel derived from atmospheric CO2

Catalysis for the Valorization of Low-Value C-Streams

The need for a better carbon management and the reduction of CO2 emissions push away from the linear-carbon economy (LCE) towards a better carbon management including carbon recycling (CR). This implies the utilization of gaseous and liquid process streams so far under-utilized, and often either sent to combustion or disposed of. In this paper, four cases are discussed, namely: low-alkane streams, industrial CO2, ligno-cellulosic waste and salty-watery-glycerol. The role of catalysis in the valorization of such C-sources is discussed and examples of innovative processes are presented

Merging the Green-H2 production with Carbon Recycling for stepping towards the Carbon Cyclic Economy

Hydrogen Economy and Cyclic Economy are advocated, together with the use of perennial (solar, wind, hydro, geo-power, SWHG) and renewable (biomass) energy sources, for defossilizing anthropic activities and mitigating climate change. Each option has intrinsic limits that prevent a stand-alone success in reaching the target. Humans have recycled goods (metals, water, paper, and now plastics) to a different extent since very long time. Recycling carbon (which is already performed at the industrial level in the form of CO2 utilization and with recycling paper and plastics) is a key point for the future. The conversion of CO2 into chemicals and materials is carried out since the late 1800s (Solvay process) and is today performed at scale of 230 Mt/y. It is time to implement on a scale of several Gt/y the conversion of CO2 into energy products, possibly mimicking Nature which does not use hydrogen.In the short term, a few conditions must be met to make operative on a large scale the production of fuels from recycled-C, namely the availability of low-cost: i. abundant, pure concentrated streams of CO2, ii. non-fossil primary energy sources, and iii. non-fossil-hydrogen. The large-scale production of hydrogen by Methane Steam Reforming with CO2 capture (Blue-H2) seems to be a realistic and sustainable solution. Green-H2 could in principle be produced on a large scale through the electrolysis of water powered by perennial primary sources, but hurdles such as the availability of materials for the construction of long-living, robust electrochemical cells (membranes, electrodes) must be abated for a substantial scale-up with respect to existing capacity. The actual political situation makes difficult to rely on external supplies.Supposed that cheap hydrogen will be available, its direct use in energy production can be confronted with the indirect use that implies the hydrogenation of CO2 into fuels (E-fuels), an almost ready technology. The two strategies have both pros and cons and can be integrated. E-Fuels can also represent an option for storing the energy of intermittent sources.In the medium-long term, the direct co-processing of CO2 and water via co-electrolysis may avoid the production/transport/ use of hydrogen.In the long term, coprocessing of CO2 and H2O to fuels via photochemical or photoelectrochemical processes can become a strategic technology