Novel Carbon Dioxide Utilization Technologies and Scaleup Opportunities

The transition to a low-carbon economy requires innovative strategies for carbon utilization that balance environmental sustainability with economic feasibility. The Fischer-Tropsch (F-T) process, a pathway for transforming syngas (CO and H2) into hydrocarbons, is garnering attention for its potential to repurpose carbon-rich feedstocks (e.g., captured CO2, waste biomass, or industrial off-gases) into value-added products. While sustainable aviation fuel (SAF) remains a flagship output of F-T technology, high-purity synthetic waxes and other specialty hydrocarbons derived from the process hold immense promise for niche markets where consistent quality and ultra-clean properties are paramount.
This presentation will explore the dual potential of F-T-derived hydrocarbons: first, as a renewable energy source in the aviation sector, aiding decarbonization of this hard-to-electrify industry; and second, as a source of synthetic waxes and lubricants with applications in diverse industries. High-purity waxes find significant demand in sectors such as pharmaceuticals, cosmetics, adhesives, and advanced manufacturing, enabled by their consistent composition, low toxicity, and desirable melting points. Similarly, F-T-derived clean hydrocarbons are of growing interest to specialty chemical and automotive industries for high-performance lubricants, ensuring superior thermal stability and reduced environmental impact.
By reconceptualizing the outputs of the F-T process beyond fuels, this work highlights how integrated carbon utilization frameworks can provide economic incentives for adoption while supporting global decarbonization goals. This perspective offers insights on tailoring F-T processes to meet the demands of these high-value markets and expands the narrative of carbon utilization into diverse end-user sectors.

CO₂ conversion into energy and value-added fuels, material, and chemicals creates economic logic for its capture. Yet CO₂ utilization at meaningful scale is fundamentally constrained by efficiency, land use, and product selectivity. Here, we present an electro-biodiesel platform that integrates CO₂ electroreduction with engineered microbial lipid biosynthesis, offering a viable pathway from captured CO₂ to diesel-range fuels.
Our system couples CO₂ electroreduction to biocompatible C2 intermediates with microbial conversion into lipids, overcoming intrinsic limitations of both standalone electrocatalysis and photosynthesis-based biofuels. Through systems-level metabolic analysis, we identify bioenergetic and metabolic bottlenecks (e.g. ATP limitation, redox imbalance, and acidification) that restrict C2 utilization. These constraints are then resolved via synthetic biology strategies that rebalance reducing equivalents and energy metabolism, unlocking efficient lipid synthesis from mixed ethanol/acetate derived from CO₂ reduction. Guided by these biological insights, we co-design bimetallic electrocatalysts to tune CO₂ reduction product distributions, enabling synergistic catalyst-microbe coupling rather than system incompatibility.
The resulting electro-biomanufacturing route achieves up to 4.5% solar-to-molecule efficiency, approximately 45-fold lower land use than conventional biodiesel, and competitive projected fuel economics with substantial life-cycle carbon reductions. Beyond biodiesel, the platform illustrates a broader paradigm for CO₂ utilization: co-designing electrochemical and biological systems together to meet the realities of scale, energy inputs, and infrastructure integration. We discuss pathways to commercialization, including factors such as electricity sourcing, process efficiency, and CO₂ feedstock availability, positioning electro-bioconversion as a scalable pillar of the emerging CCUS ecosystem.

The conversion of carbon dioxide into value-added chemicals often proceeds through reaction networks involving water, hydrogen, and other carbon (C)–hydrogen (H)–oxygen (O) containing feed combinations. In such systems, feasibility is governed not only by stoichiometric constraints, but also by how heat and work are exchanged with the environment and redistributed across coupled chemical transformations. For any proposed reaction network, overall process feasibility is determined by changes in Gibbs free energy, which define the minimum reversible work required for a desired chemical transformation. Real processes inevitably require additional work due to irreversibility arising from reaction pathway selection and operating conditions. When CO₂ is used as a feedstock, the Gibbs free energy changes associated with reduction reactions are inherently large, making pathway selection and energy input strategy central to process viability.

Although many proposed CO₂ utilization routes emphasize individual reaction steps or catalytic and kinetic performance, a unified framework that simultaneously accounts for reaction attainability and process-level energy feasibility remains limited. A combined analysis of reaction pathways and process heat and work flows is therefore essential for identifying economically and environmentally viable routes for converting CO₂ into fuels and chemicals such as methanol, ethanol, formic acid, and oxalic acid.

In this work, we introduce a combined stoichiometric and thermodynamic attainable region framework that separates reaction pathway feasibility from process feasibility while enabling their coordinated analysis. Reaction feasibility is evaluated through elemental mass-fraction and reaction-extent attainable regions in CHO space, defining all stoichiometrically compatible feed–product relationships independent of reaction mechanism. Process feasibility is subsequently assessed by mapping attainable reaction outcomes into enthalpy–Gibbs free energy (H–G) space, distinguishing pathways achievable within a single process step from those that inherently require multiple steps involving thermal, electrochemical, or work-driven operations.

By treating reaction and process feasibility as distinct but complementary design layers, the framework provides a early-stage screening of CO₂ utilization pathways, avoiding thermodynamically inefficient routes and supports the design of scalable, energy efficient low-carbon chemical technologies..

The use of excess CO₂ as a renewable feedstock requires conversion processes which can tolerate impure, particularly to enable distributed manufacturing where pipelines of high-purity CO₂ are unavailable. Most work on electrochemical CO₂ reduction (eCO₂R) uses feeds of pure CO₂, while realistic feed streams are largely overlooked. Previous work on eCO₂R to CO establishes that feeds should ideally contain ≥40% CO₂ (in N₂) for useful Faradaic efficiencies. Meanwhile, as little as 1% O₂ in the feed drastically reduces performance due to the competing O₂ reduction reaction. Thus, pairing CO₂ capture and conversion requires a CO₂ capture process which is capable of (1) generating streams of ≥40% CO₂ and <1% O₂ for eCO₂R and (2) operating with minimal infrastructure needs. Poly(dimethylsiloxane) (PDMS) nanomembranes (≤1 μm thick) offer this possibility. Using only vacuum pumps and nanomembranes made of commercial polymers, this modular technology can be implemented using a multistage approach to tailor the product composition. We show that CO₂ capture-and-conversion processes depend importantly on CO₂ capture performance and develop strategies to overcome emergent barriers towards integrating CO₂ capture and conversion.

Using ternary CO₂/N₂/O₂ feed gases from synthetic air to synthetic flue gases (0.04–10% CO₂), we show experimentally that the feed [O₂] critically governs multistage CO₂ capture performance, especially for feeds of [CO₂] < 5%. Thus, although realistic CO₂ waste streams have [N₂] > [O₂], we show that even modest [O₂] cannot be ignored, suggesting removal of O₂ before CO₂ capture. We then show that undesired O₂ enrichment during CO₂ capture can be mitigated by removing O₂ such that the feed ratio [CO₂]/[O₂] ≥ 0.91, defining the upper limits of feed [O₂]. We also show that the total energy demand of CO₂ capture and O₂ removal is reduced by removing O₂ upstream, eliminating unnecessary capture stages and raising CO₂ recoveries. Based on our findings, we use these strategies to integrate CO₂ capture, O₂ removal, and eCO₂R. We furthermore demonstrate integrated CO₂ capture and simultaneous valorization of representative CO₂ waste gases and biomass waste through electrochemical co-conversion to value-added products. This work highlights important considerations for unit operations which are needed to enable scalable CO₂ utilization, accelerating progress towards CO₂ capture-and-conversion systems for a CO₂-based circular economy.

The growing demand for technologies to capture, utilize, and sequester CO2, bolstered by government and public realization of meeting global energy demands and climate goals, is a critical opportunity for the chemical and process industries. There has been a building momentum in the field arising from investment incentives and the civic value of meeting climate targets. At SwRI, we have integrated teams working on all facets of CCUS and related infrastructure developed for real-world CO2 producers. Our expertise ranges over chemisorption, membrane and oxy-fuel separations, chemical and calcium looping, direct air capture, infrastructure and logistics, and supercritical CO2 power cycles. SwRI has developed a novel technology to convert CO2 into different carbonaceous forms including graphene through a metallothermic reduction reaction. Leveraging high dollar value markets with newly coming-online carbon capture projects has the potential to change the perception of CCUS worldwide by shifting the perspective of CCUS from having little cost benefit to a lucrative opportunity. The focus of the research conducted by SwRI is to explore an experimental method of graphene production in a novel process in which carbon dioxide is reduced to carbon via vapor-liquid metallothermic reduction. The scope of the research aimed to determine the requirements and viability of building and operating a plant utilizing this process at scale through bench scale experimentation of the metallothermic reduction and a subsequent techno-economic analysis utilizing process data. The process concept developed at SwRI revolves around a molten metal reduction of CO2 to carbon that can be operated in a semi-batch process. Operation of the bench scale unit utilized a specialized stirred crucible melting furnace modified to operate safely in our facility, completing a test matrix to determine optimal process conditions. Furthermore, a detailed simulation for the process was built using Aspen Plus which fed into a subsequent techno-economic assessment to evaluate feasibility and scalability. This presentation will discuss detailed results and observations of the research effort as a case study for development of scalable carbon utilization technologies.

Electrochemical sorbent control is a emerging energy efficient alternative to heat-driven chemical separations. One promising application is acid gas separations, e.g., carbon capture from mixed gas streams, because the primary limitation to the adoption of the state-of-the-art heat-driven process is its high energy demand. In the electrochemical approach, a chemical sorbent cycles between active and inactive oxidation states, driving the absorption or desorption of CO2 for selective and regenerable separation with a readily reversible redox reaction. While the fundamental chemistry of this new process builds on foundations from other application areas like batteries and fuel cells, its energy efficiency — the technology’s main selling point — has not been as low as promised in laboratory experiments. To address this gap, we used a multi-objective systems modeling approach to discern the nonlinear relationships between chemical properties of interest and the most important system performance metrics of energy demand and capture rate. We specifically found that certain “conventional wisdom” assumptions that have dictated the focus of much recent research — e.g, that performance is monotonic with sorbent basicity — are not only incorrect but also of low impact compared to other chemical properties. This discussion will conclude with preliminary findings from our current research efforts focused on the more impactful properties that our systems analyses identified like absorption kinetics and sorbent solubility.

This work focuses on the search for universal organic photo(electro)catalysts capable of driving consecutive photoinduced electron transfer photocatalysis (conPET) and electro-photoredox catalysis (e-PRC). Both approaches use visible light and/or electricity as clean reagents to promote challenging organic reactions, aiming to improve atom economy and reduce waste.

The proposed organic catalysts are naphthalene-diimide (NDI) derivatives, due to their electron deficient aromatic core and stability of their radical anions. Besides, substitutions in their aromatic positions has allowed the formation of stable radical cations and anions. Hence, three NDIs disubstituted at the 2- and 6- positions were synthesized with electron-donating groups to increase electron density on the aromatic core (NDI-N₂, NDI-O₂ and NDI-S₂, Figure 1). The synthesis is a three-step sequence starting from naphthalene dianhydride (NDA). The unsubstituted analogue NDI-H₂ was also synthesized and studied for comparison. Spectro(electro)chemical characterization of the four NDIs demonstrated their ability to form radical anions which absorb visible light and are stable enough (under N₂) to propose their use in reductive conPET or e-PRC. On the other hand, only NDI-N₂ can form a radical cation with UV-visible absorption and stability suitable for an oxidative version of the mentioned processes.

The catalytic performance of these NDIs was then evaluated under conPET and e-PRC conditions, using blue LEDs and electricity as energy sources to promote oxidative and reductive transformations. Regarding conPET, the thiocyanation of indoles and styrene using CO₂ as the terminal oxidant was studied; this model reaction couples substrate oxidation by excitation of neutral NDI and CO₂ reduction via excitation of radical anion. For e-PRC, two model reactions were examined: on the one hand, the oxidative cyclization of thiobenzanilides involving Csp²-S bond formation and, on the other hand, the electrochemical reduction of CO₂, involving the excitation of radical cation and radical anion respectively. In both approaches, all components -NDI catalyst, visible light, and either a terminal oxidant (conPET) or electricity (e-PRC)- were required for reactivity.