The distinction between storage and utilization is more than semantic. Conventional carbon capture and storage, along with afforestation and geological sequestration, can mitigate emissions, but these approaches generate limited economic value and leave CO2 locked away as a liability rather than exploited as a renewable resource. Carbon capture and utilization, or CCU, flips the equation: captured CO2 is transformed into value-added products such as methane, methanol, polymers, and other materials, creating commercial incentives that can help finance the capture infrastructure itself. While CCU has traditionally concentrated on fuels and bulk commodities, the review highlights how recent advances are pushing CO2 chemistry into far more ambitious territory — specialty chemicals, non-natural products, and functional materials that were previously inaccessible from a one-carbon feedstock.

What makes CO2 an attractive synthon despite its notorious stability is the sheer abundance of the resource. Every tonne of emitted CO2 represents a reservoir of reduced-carbon potential waiting to be reactivated, and unlike biomass or fossil feedstocks, the supply is effectively unlimited and geographically unconstrained. The challenge lies in the chemistry. Carbon in CO2 sits at its highest oxidation state, so converting it into useful reduced molecules — hydrocarbons, alcohols, polymers — demands substantial energy input and highly selective catalysis. The review surveys how researchers are meeting that challenge across four converging fronts: thermal catalysis, electrochemistry, photochemistry, and biology.

Catalytic strategies remain the industrial workhorse, and recent developments have focused on improving carbon selectivity, the ability to steer reactions toward one desired product rather than a mixture. Enhanced selectivity matters enormously for economics: a process that yields mostly methanol is far easier to commercialize than one producing a soup of alcohols, aldehydes, and hydrocarbons that must be separated at cost. The authors describe how state-of-the-art catalysts are achieving finer control over carbon–carbon bond formation, enabling longer and more complex product chains than the methanol-and-methane chemistry that dominated early CCU efforts. That progression toward higher product complexity is what allows CO2 to graduate from commodity fuel precursor to feedstock for specialty manufacturing.

Electrochemical and photochemical routes add a different kind of flexibility. Electrochemical CO2 reduction can, in principle, run on renewable electricity at ambient conditions, coupling directly to intermittent solar and wind power and converting surplus electrons into stored chemical value. Photochemical approaches go further, using light itself to drive the fixation of CO2 into organic frameworks. Both strategies are examined in the review as programmable carbon fixation platforms — systems where reaction conditions, catalyst design, and energy input can be tuned to dictate which bonds form and where. This programmability is central to the review’s vision of CO2 as a synthon rather than merely a substrate: a synthon, by definition, is a fragment whose reactivity can be directed toward many different molecular destinations.

Perhaps the most striking section of the review concerns biological interventions that push carbon utilization beyond native metabolic constraints. Natural organisms already fix CO2 through photosynthesis and a handful of autotrophic pathways, but the products accessible through these routes are limited by evolution’s menu. Synthetic biology and metabolic engineering are now expanding that menu, rewiring microbial metabolism so that captured carbon can be channeled into structurally diverse and functionally tailored molecules — including non-natural compounds that no organism has ever produced. The authors single out these emerging biological strategies as key enablers for biomedical applications, where CO2-derived building blocks could feed into the synthesis of pharmaceutical intermediates, biocompatible polymers, and other high-value health-related products.

The biomedical angle illustrates how far the field has traveled from its origins. Early CCU discussions centered almost entirely on fuels — a way to recycle carbon into gasoline and diesel substitutes. The review’s emphasis on specialty chemicals, advanced materials, and medical applications signals a maturing discipline that recognizes where the margins actually are. A kilogram of CO2-derived polymer additive or pharmaceutical precursor commands a far higher price than a kilogram of synthetic fuel, and high-value products can anchor early markets while bulk applications scale. Functional materials, in particular, are highlighted as an emerging opportunity class, with CO2-derived monomers and carbonates feeding into polymers whose properties can be engineered for specific end uses.

None of this translates into industrial impact without process integration and economic viability, and the review devotes substantial attention to the factors governing commercialization. Scalability remains the perennial hurdle: laboratory electrolysers and bioreactors that perform beautifully at milliliter scale must be redesigned for the tonne-per-day regime, with attention to electrode durability, catalyst lifetime, heat management, and separation costs. Techno-economic feasibility analyses, the authors note, are essential for identifying which product routes can compete with fossil-derived incumbents and which remain aspirational. Process integration — coupling CO2 conversion with capture plants, renewable power sources, and existing chemical infrastructure — determines whether a utilization pathway closes the carbon loop or merely relocates the emissions problem.

The review also frames the bigger picture: establishing scalable, economically viable, net-zero carbon technologies requires developments on both the technological and translational fronts simultaneously. Better catalysts and engineered microbes are necessary but not sufficient; the field equally needs reliable supply chains for captured CO2, regulatory frameworks that credit utilization in carbon accounting, and partnerships between chemical manufacturers, energy providers, and biotechnology firms. The authors present future perspectives outlining what must happen for CO2 utilization to move from promising pilot projects to a structural pillar of low-carbon manufacturing.

The trajectory the review describes is ultimately one of reframing. CO2 is evolving, in the authors’ words, from an environmental burden into a renewable feedstock for high-value manufacturing — a molecule whose destiny is written not by its emissions past but by the selectivity of the catalysts, the programmability of the fixation chemistry, and the imagination of the engineers and biologists who direct its reactivity. If the technological and economic barriers catalogued in the analysis can be cleared, the same gas that drives climate change could become the carbon backbone of fuels, polymers, materials, and medicines in a circular economy, with every captured tonne representing not a disposal cost but a manufacturing opportunity.

Subject of Research: CO2 as a sustainable carbon synthon for advanced chemical manufacturing

Article Title: CO2 as a sustainable carbon synthon for advanced chemical manufacturing

Article References: Raheja, Y., Gupta, P., Singh, S., Gautam, K., Aishwarya, A., Kumar, A., Chauhan, R., Chadha, B. S., Srivastava, J. K., & Gaur, V. K. (2026). CO2 as a sustainable carbon synthon for advanced chemical manufacturing. Frontiers in Chemical Engineering, 8, Article 1896459. https://doi.org/10.3389/fceng.2026.1896459

Image Credits: AI Generated

DOI: 10.3389/fceng.2026.1896459

Keywords: carbon capture and utilization, CO2 conversion, sustainable chemistry, carbon circularity, catalysis, electrochemical reduction, synthetic biology, green manufacturing, sustainable, carbon, synthon, advanced