William Wilson McNeary

Thermochemical reactive carbon capture (tRCC) offers a direct pathway to convert dilute CO ₂ into valuable fuels and chemicals. However, the scalability of tRCC is hindered by the thermal inertia of conventional reactors, which limits reactor throughput. Here, we report the first demonstration of magnetically induced reactive carbon capture (mRCC), utilizing high‐frequency alternating magnetic fields to drive rapid heating (200–400°C/min) of alkali‐impregnated ferromagnetic catalysts. Operating as multi‐function materials (MFMs), these sorbent–catalysts achieve high temperatures in minutes rather than hours, capturing and selectively converting dilute CO ₂ into methane. Surprisingly, the optimal Na/NiFe exhibited stable CH ₄ productivity under mRCC but was rendered inactive under equivalent conventional heating. Utilizing a novel magnetically programmed reduction (MPR) technique alongside in situ DRIFTS and STEM‐EELS, we reveal that contact heating under reducing conditions drives phase segregation and alkali migration, eliminating the material's CO ₂ capture capability. In contrast, localized magnetic heating preserves the functionality of the alkali capture sites while creating a reactive surface hydrogen pool. These findings show that magnetic induction does not merely accelerate heating but fundamentally alters the local catalyst–sorbent environment. Ultimately, this work establishes critical design principles for induction‐heated catalysis and advances mRCC as a scalable power‐to‐X strategy for rapid carbon valorization.

Thermochemical reactive carbon capture (tRCC) offers a direct pathway to convert dilute CO ₂ into valuable fuels and chemicals. However, the scalability of tRCC is hindered by the thermal inertia of conventional reactors, which limits reactor throughput. Here, we report the first demonstration of magnetically induced reactive carbon capture (mRCC), utilizing high‐frequency alternating magnetic fields to drive rapid heating (200–400°C/min) of alkali‐impregnated ferromagnetic catalysts. Operating as multi‐function materials (MFMs), these sorbent–catalysts achieve high temperatures in minutes rather than hours, capturing and selectively converting dilute CO ₂ into methane. Surprisingly, the optimal Na/NiFe exhibited stable CH ₄ productivity under mRCC but was rendered inactive under equivalent conventional heating. Utilizing a novel magnetically programmed reduction (MPR) technique alongside in situ DRIFTS and STEM‐EELS, we reveal that contact heating under reducing conditions drives phase segregation and alkali migration, eliminating the material's CO ₂ capture capability. In contrast, localized magnetic heating preserves the functionality of the alkali capture sites while creating a reactive surface hydrogen pool. These findings show that magnetic induction does not merely accelerate heating but fundamentally alters the local catalyst–sorbent environment. Ultimately, this work establishes critical design principles for induction‐heated catalysis and advances mRCC as a scalable power‐to‐X strategy for rapid carbon valorization.

Molecular catalysts, such as metalated porphyrins, are attractive cocatalysts for photocatalytic water splitting owing to their potential to simultaneously catalyze target reactions at their metal center, extend charge-separated-state lifetimes, and accumulate the requisite charge for product formation. However, porphyrin catalysts, like most molecular catalysts, are often limited by poor stability associated with demetalation, inactivation by undesired bonding (e.g., O₂ coordination/redox/dimerization), and detachment from electrode supports or semiconducting photoabsorbers. In this study, nanoscopic titanium dioxide (TiO₂) overlayers, deposited by atomic layer deposition (ALD), are demonstrated to encapsulate cobalt(III) meso-tetra(4-carboxyphenyl) porphyrin chloride (CoTCPP) molecular catalysts and thereby improve their adhesion to electrode surfaces over a wide range of electrode potentials spanning from −1.0 V vs RHE to +1.8 V vs RHE. Through analysis of Raman and ultraviolet–visible spectroscopy, it was confirmed that the metalloporphyrin structure was maintained when the surface-bound CoTCPP was encapsulated by 10 – 250 ALD cycles (≈2 – 18 nm thick) of TiO₂. Additional characterization of CoTCPP catalysts before and after electrochemical measurements reveals that up to 97% of the encapsulated CoTCPP remains tethered to the electrode surface after chronoamperometry tests under hydrogen evolution reaction (HER) conditions, compared to <36% for unencapsulated CoTCPP. This study also shows that encapsulated CoTCPP molecules remain partially redox active for overlayers up to 8 nm, which can also attenuate undesired redox mediator back reactions like ferricyanide reduction.

Scaling conventional carbon capture and utilization methods can be limited by cost and permitting issues associated with transportation of captured CO2. Reactive carbon capture (RCC), in which a single solid-phase dual function material (DFM) is used to both capture CO2 from dilute streams (e.g., flue gas) and catalytically convert the bound species to products in a single unit operation, has the potential to reduce energy and capital costs by over 50% relative to separate capture and conversion. To incentivize adoption, high-value products such as methanol and CO should be targeted. Appealingly, CO can be produced at atmospheric pressure, thereby lowering overall H2 demand; however, high reaction temperatures (> 600 degrees C) and the use of oxidizable transition metals, such as Ni, are often necessary to drive the reverse water-gas shift (RWGS) during reactive desorption of the bound CO2. The sensitivity of these transition metals to oxygen undercuts their utility in point source RCC. To further derisk RCC, it is essential to develop metallic-phase free DFMs that are insensitive to residual oxygen in flue gas and can achieve selective reactive desorption to CO at moderate pressures (< 400 degrees C). To this end, we have developed K-modified Zn-Al mixed oxides (K/ZnAlOx) to convert captured CO2 to CO with > 97% selectivity and yields up to 53% of captured CO2 at 400 degrees C. Complementary in situ spectroscopy studies revealed the role of K-modification in improving RCC performance of unmodified ZnAlOx. The top performing DFM was also subjected to extended RCC cycling with oxygen co-fed with CO2 during the capture test to assess durability under simulated flue gas.

Direct air capture (DAC) has received significant attention this decade as a viable solution to limit global warming, although large-scale deployment is currently not economically feasible. To reach the ambitious cost target set by the U.S. of $100/ton CO2 captured and stored, significant improvements must be made to sorbent lifetime and capacity. Aminosilanes grafted onto silica supports are promising candidates for deployment in DAC systems due to their relatively high oxidative stability and low regeneration temperature. Despite myriad advancements in the field, there still exists a fundamental knowledge gap relating sorbent structure to performance. In this work, we grafted various aminosilanes onto the highly porous silica SBA-15 and characterized both oxidative stability and CO2 capacity. Material properties systematically investigated included amine moiety (primary vs. secondary), silane group structure, number of linkages to the silica support, and co-addition of impregnated amines (e.g., PEI), among others. A fixed bed system was used to execute accelerated degradation studies in the presence of humidity and varying temperatures to simulate realistic operating conditions. Atomistic simulations were combined with the experimental results to gain mechanistic insight, ultimately informing the design of next-generation materials

The goals of this project are to design and develop tailored dual-functional materials (DFMs) and the accompanying pressure-swing process for the reactive capture and conversion (RCC) of CO2 to methanol, a vital product in the chemical market and a versatile precursor to fuels. Throughout this project, NREL researcher team has successfully developed 2 groups of DFM and associated cyclic RCC procedure to selectivity produce either methanol or CO, which is a major intermediate for methanol synthesis with commercially available technologies. Additionally, this project has also developed process models and techno-economic analysis (TEA) and life cycle assessment (LCA) framework to evaThe goals of this project are to design and develop tailored dual-functional materials (DFMs) and the accompanying pressure-swing process for the reactive capture and conversion (RCC) of CO2 to methanol, a vital product in the chemical market and a versatile precursor to fuels. The proposed approach is based on the hypothesis that precise co-location of basic and metallic sites in a DFM will enable efficient RCC of CO2 in a fixed-bed temperature-pressure-swing reactor under mild conditions that favor lower capital and operating expenses and offer compatibility with a dynamic energy grid to provide favorable process economics. The proposed hybrid process utilizes renewable H2 and targets deployment at a gas-fired power plant, where CO2 point sources have relatively high CO2 capture costs by traditional methods, ranging from 43 to 89 $/ton, suggesting that the economics would benefit from an RCC approach. This choice of CO2 source represents a relatively lower carbon capture rate (0.47 MMTCO2 per plant year), but with a high number of plants (>1100). This deployment plan holds the potential to achieve relevant carbon capture and utilization magnitudes through modular implementation of the process, where initial estimates suggest that the current annual production rate of renewable methanol (0.2 MMT/year) could be equaled upon the first installation of the proposed technology. Throughout this project, NREL researcher team has successfully developed 2 groups of DFM and associated cyclic RCC procedure to selectivity produce either methanol or CO, which is a major intermediate for methanol synthesis with commercially available technologies. Additionally, this project has also developed process models and techno-economic analysis (TEA) and life cycle assessment (LCA) framework to evaluate feasibility of the developed DFM and processes. The TEA/LCA framework includes integration of RCC process models developed using ASPEN Plus and optimization of renewable hydrogen generation and supply for RCC process using NREL's developed H2INTEGRATE tool. The detailed results of this project are reported below in 3 major sections: 1. Development of DFM for RCC to produce methanol; 2. Development of DFM for RCC to produce CO; 3. Development of TEA and LCA framework for technology feasibility evaluation. Additionally, major milestone achievements are summarized in section 4 with scientific products, including publications, patents, posters and presentations are listed in section 5. Section 6 provides a quarterly budget summary for the project.

Reactive CO₂ capture (RCC) is a promising strategy for process intensification of carbon capture and conversion for production of low-carbon fuels and chemicals. As state-of-the-art sorbent materials in point source and direct air capture systems, solid-supported amines are a natural choice to pair with supported CO₂ hydrogenation catalysts (e.g., metallic nanoparticles) for developing high-capacity sorbent-catalyst materials for use in RCC. In this Perspective, we summarize the relevant literature combining solid-supported amines with metallic nanoparticles for thermocatalytic RCC and detail two of our own case studies using RCC to synthesize methane and methanol. Our observations suggest that the temperature mismatch between CO₂ desorption and reaction, along with potential catalyst site poisoning by grafted aminosilanes, is a significant obstacle to realizing the potential of amine-based RCC materials in the decarbonization of chemical production. This stands in contrast to literature detailing successful RCC using liquid amines and solid catalysts, which may benefit from more favorable mass transfer dynamics, as well as early stage reports into RCC solid-phase amine-Pd materials, whose findings we were not able to replicate. More judicious reaction selection and synthetic design strategies to match materials with process conditions offer alternative pathways for future research.

Photocatalytic water splitting is a promising route to low-cost, green H₂. However, this approach is currently limited in its solar-to-hydrogen conversion efficiency. One major source of efficiency loss is attributed to the high rates of undesired side and back reactions, which are exacerbated by the proximity of neighboring oxidation and reduction sites. Nanoscopic oxide coatings have previously been used to selectively block undesired reactants from reaching active sites; however, a coating encapsulating the entire photocatalyst particle limits activity as it cannot facilitate both half-reactions. In this work, area selective atomic layer deposition (AS-ALD) was used to selectively deposit semipermeable TiO₂ films onto model metallic cocatalysts for enhancing reaction selectivity while maintaining a high overall activity. Pt and Au were used as exemplary reduction and oxidation cocatalyst sites, respectively, where Au was deactivated toward ALD growth through self-assembled thiol monolayers while TiO₂ was coated onto Pt sites. Electroanalytical measurements of monometallic thin film electrodes showed that the TiO₂-encapsulated Pt effectively suppressed undesired H₂ oxidation and Fe(II)/Fe(III) redox reactions while still permitting the desired hydrogen evolution reaction (HER). A planar model photocatalyst platform containing patterned interdigitated arrays of Au and Pt microelectrodes was further assessed using scanning electrochemical microscopy (SECM), demonstrating the successful use of AS-ALD to enable local reaction selectivity in a dual-reaction-site (photo)electrocatalytic system. Finally, interdigitated microelectrodes having independent potential control were used to show that selectively deposited TiO₂ coatings can suppress the rate of back reactions on neighboring active sites by an order of magnitude compared with uncoated control samples.