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At least 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

CeO 2 Promoted CuO/MgO-Al 2 O 3 Catalyst with Enhanced Activity and Water-Resistance for CO Oxidation

Copper (Cu)-based catalysts have emerged as cost-effective and sustainable alternatives to noble metal systems (e.g., Pt, Pd) for catalytic CO oxidation. However, their practical application is hindered by insufficient low-temperature activity and rapid deactivation under wet conditions containing moisture. To address these challenges, this work introduces CeO 2 -modified CuO/MgO-Al 2 O 3 (Cu-Ce/MA) catalysts, strategically designed to enhance the catalytic performance and water resistance simultaneously. These catalytic materials were evaluated for CO oxidation under both dry and humid conditions, revealing that CeO 2 modification significantly improves the low-temperature activity. Specifically, the optimal catalyst, Cu-30Ce/MA, achieved a 50% CO conversion temperature (T 50 ) of 151 °C, a marked reduction from 218 °C on Cu/MA reference catalyst. Furthermore, the water resistance improves in a CeO 2 content-dependent manner, with higher CeO 2 loadings imparting greater stability in humid environments. Detailed characterizations demonstrate that CeO 2 promotes the dispersion of CuO and stabilizes Cu sites, while also enhancing the low-temperature reducibility and CO adsorption capacity. Crucially, CeO 2 modification suppresses the competitive H 2 O adsorption, mitigating water-induced deactivation. These synergistic effects collectively rationalize the superior activity and durability of Cu-Ce/MA catalysts. By elucidating the dual role of CeO 2 in optimizing Cu-based systems, this study advances the rational design of cost-effective catalysts for real-world CO emission control, particularly under water-rich industrial conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Multimodal Nanoscale Mapping of Local Structure and CO 2 Adsorption in Metal–Organic Frameworks

Diamine functionalization of the metal−organic framework Mg 2 (dobpdc) (dobpdc 4− = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate) significantly enhances its selectivity for CO 2 capture from flue gases and air. The structure and CO 2 capacity of such materials are typically assessed using bulk techniques that rely on averaging signal over large ensembles of unit cells, obscuring local heterogeneities, such as variations in CO 2 occupancy across individual nanocrystals. To resolve this limitation, we demonstrate a multimodal, nanoscale characterization of Mg 2 (dobpdc) appended with 1,3-diaminopropane. By employing recently developed characterization techniques at progressively smaller length scales, we uncover insights from correspondingly smaller populations of unit cells. First, we use parallel-beam 3D electron diffraction (3D ED) to identify a prominent expansion in lattice parameters upon desorption of CO 2 , as observed at the level of single nanocrystals. Second, we use convergent-probe 4D scanning transmission electron microscopy (4D-STEM) to quantify associated differences in lattice strain as a function of gas loading and diamine appending. These measurements sample small subvolumes within individual nanocrystals. Finally, we apply infrared scattering scanning near-field optical microscopy (IR s- SNOM) to confirm variable CO 2 chemisorption across adsorption sites at the surface of single nanocrystals. This multimodal, multiscale approach allows us to map heterogeneity within individual nanocrystals. Collectively, these findings emphasize the importance of local, nanoscale characterization of metal−organic frameworks in revealing previously unresolvable features that impact their performance.

Karstens, Sarah L. [University of California, Berk↗
DOE OSTI2020

Materials Data on Co(PdSe)2 by Materials Project

Pd2CoSe2 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. Co is bonded to four equivalent Pd and four equivalent Se atoms to form distorted face-sharing CoPd4Se4 tetrahedra. All Co–Pd bond lengths are 2.86 Å. All Co–Se bond lengths are 2.34 Å. Pd is bonded in a 4-coordinate geometry to two equivalent Co, three equivalent Pd, and five equivalent Se atoms. There are one shorter (2.83 Å) and two longer (2.93 Å) Pd–Pd bond lengths. There are a spread of Pd–Se bond distances ranging from 2.52–2.88 Å. Se is bonded in a 7-coordinate geometry to two equivalent Co and five equivalent Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KCo(CO)4 by Materials Project

KCo(CO)4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.76–3.26 Å. In the second K1+ site, K1+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.75–3.14 Å. In the third K1+ site, K1+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.74–3.21 Å. In the fourth K1+ site, K1+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.74–3.25 Å. There are four inequivalent Co1+ sites. In the first Co1+ site, Co1+ is bonded in a tetrahedral geometry to four C+1.50+ atoms. There are a spread of Co–C bond distances ranging from 1.73–1.75 Å. In the second Co1+ site, Co1+ is bonded in a tetrahedral geometry to four C+1.50+ atoms. There is three shorter (1.74 Å) and one longer (1.75 Å) Co–C bond length. In the third Co1+ site, Co1+ is bonded in a tetrahedral geometry to four C+1.50+ atoms. There is three shorter (1.74 Å) and one longer (1.75 Å) Co–C bond length. In the fourth Co1+ site, Co1+ is bonded in a tetrahedral geometry to four C+1.50+ atoms. There is three shorter (1.74 Å) and one longer (1.75 Å) Co–C bond length. There are sixteen inequivalent C+1.50+ sites. In the first C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.18 Å. In the second C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.17 Å. In the third C+1.50+ site, C+1.50+ is bonded in a distorted linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.17 Å. In the fourth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.17 Å. In the fifth C+1.50+ site, C+1.50+ is bonded in a distorted linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.18 Å. In the sixth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.17 Å. In the seventh C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.17 Å. In the eighth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.17 Å. In the ninth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.18 Å. In the tenth C+1.50+ site, C+1.50+ is bonded in a distorted linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.18 Å. In the eleventh C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.17 Å. In the twelfth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.18 Å. In the thirteenth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.17 Å. In the fourteenth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.18 Å. In the fifteenth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.18 Å. In the sixteenth C+1.50+ site, C+1.50+ is bonded in a linear geometry to one Co1+ and one O2- atom. The C–O bond length is 1.18 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one C+1.50+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to one K1+ and one C+1.50+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one C+1.50+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to one K1+ and one C+1.50+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to one K1+ and one C+1.50+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one C+1.50+ atom. In the seventh O2- site, O2- is bonded in a distorted linear geometry to one K1+ and one C+1.50+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one C+1.50+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one C+1.50+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one C+1.50+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one C+1.50+ atom. In the twelfth O2- site, O2- is bonded in a distorted linear geometry to one K1+ and one C+1.50+ atom. In the thirteenth O2- site, O2- is bonded in a distorted linear geometry to one K1+ and one C+1.50+ atom. In the fourteenth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one C+1.50+ atom. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one C+1.50+ atom. In the sixteenth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one C+1.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Co(H3Cl)2 by Materials Project

Co(H2Cl)2H2 is Modderite-like structured and crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of two hydrogen molecules and two Co(H2Cl)2 clusters. In each Co(H2Cl)2 cluster, Co2+ is bonded in a hexagonal planar geometry to four equivalent H and two equivalent Cl1- atoms. All Co–H bond lengths are 1.64 Å. Both Co–Cl bond lengths are 2.14 Å. H is bonded in a 1-coordinate geometry to one Co2+ and one H atom. The H–H bond length is 0.82 Å. Cl1- is bonded in a single-bond geometry to one Co2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Co(BRh2)3 by Materials Project

Co(Rh2B)3 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are nine inequivalent Rh sites. In the first Rh site, Rh is bonded in a 3-coordinate geometry to three B atoms. There are one shorter (2.09 Å) and two longer (2.19 Å) Rh–B bond lengths. In the second Rh site, Rh is bonded in a 3-coordinate geometry to three B atoms. There are a spread of Rh–B bond distances ranging from 2.10–2.24 Å. In the third Rh site, Rh is bonded in a 3-coordinate geometry to three B atoms. There are one shorter (2.15 Å) and two longer (2.21 Å) Rh–B bond lengths. In the fourth Rh site, Rh is bonded in a 3-coordinate geometry to three B atoms. There are a spread of Rh–B bond distances ranging from 2.12–2.23 Å. In the fifth Rh site, Rh is bonded in a 3-coordinate geometry to three B atoms. There are one shorter (2.18 Å) and two longer (2.19 Å) Rh–B bond lengths. In the sixth Rh site, Rh is bonded in a 3-coordinate geometry to three B atoms. There are one shorter (2.15 Å) and two longer (2.16 Å) Rh–B bond lengths. In the seventh Rh site, Rh is bonded in a distorted water-like geometry to two equivalent B atoms. Both Rh–B bond lengths are 2.12 Å. In the eighth Rh site, Rh is bonded in a 2-coordinate geometry to two B atoms. There are one shorter (2.15 Å) and one longer (2.16 Å) Rh–B bond lengths. In the ninth Rh site, Rh is bonded in a distorted water-like geometry to two equivalent B atoms. Both Rh–B bond lengths are 2.12 Å. Co is bonded in a 2-coordinate geometry to two B atoms. There are one shorter (2.10 Å) and one longer (2.13 Å) Co–B bond lengths. There are four inequivalent B sites. In the first B site, B is bonded in a 6-coordinate geometry to four Rh and two equivalent Co atoms. In the second B site, B is bonded in a 6-coordinate geometry to five Rh and one Co atom. In the third B site, B is bonded in a 6-coordinate geometry to six Rh atoms. In the fourth B site, B is bonded in a 6-coordinate geometry to six Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Co(CO3)2 by Materials Project

CoO4Co(CO2)4 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of two CoO4 clusters and one Co(CO2)4 sheet oriented in the (1, 0, 0) direction. In each CoO4 cluster, Co4+ is bonded in a distorted square co-planar geometry to four equivalent O2- atoms. There is two shorter (1.74 Å) and two longer (1.75 Å) Co–O bond length. O2- is bonded in a single-bond geometry to one Co4+ atom. In the Co(CO2)4 sheet, Co4+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Co–O bond distances ranging from 2.12–2.24 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a linear geometry to two O2- atoms. Both C–O bond lengths are 1.17 Å. In the second C4+ site, C4+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.16 Å) and one longer (1.18 Å) C–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Co4+ and one C4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one C4+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Platinum–Ruthenium Alloys Are Not Bifunctional CO Electro-Oxidation Catalysts: A Kinetic Analysis

Electro-oxidation of CO is a common kinetic bottleneck in many types of fuel cells and organic electrosynthesis processes. Alloys of Pt and Ru are often used as anode catalysts, with high activity attributed to bifunctionality; this suggests that Ru preferentially activates water to form surface hydroxyl groups that can react with Pt-bound CO. However, rigorous kinetic measurements have not confirmed this assertion under steady-state electro-oxidation conditions. Here, CO electro-oxidation is analyzed using several commercial Pt/C and Pt 100-x Ru x /C nanoparticle catalysts in acidic and alkaline electrolytes. Kinetic observables including apparent transfer coefficients and reaction orders are measured and evaluated using a degree of rate control analysis. The kinetic observables for both Pt and PtRu alloys are most consistent with competitive adsorption and Langmuir–Hinshelwood coupling across a single site-type, rather than two distinct sites. Furthermore, the role of Ru in CO electro-oxidation is assigned to be a purely electronic effect.

Alcohols↗
DOE OSTI2025

An Interfacial Engineering Approach toward Operation of a Porous Solid Electrolyte CO 2 Electrolyzer

Waste CO 2 can be repurposed as a carbon feedstock for synthesizing valuable chemicals via CO 2 electrolysis. Porous solid electrolyte (PSE) CO 2 electrolysis has been demonstrated as an economically viable method to produce high purity products. This work applies an interfacial engineering approach to determine key factors to improve performance in PSE CO 2 electrolyzers. We standardize the assembly by binding the ionic resin into an ionomer wafer and utilize Computational Fluid Dynamics (CFD) to design gaskets for uniform fluid flow. Here, we employ the distribution of relaxation times (DRT) method to determine that anionic-conducting interfaces are the primary contributor to energy losses. To address this, we demonstrate that enhancing the contact between the cathode and the anion exchange membrane (AEM) and the AEM-ionic resin interface allows for low overpotential in deionized water operation.

09 BIOMASS FUELS↗
DOE OSTI2020

High-Performance, Long-Life, Rechargeable Li–CO 2 Batteries based on a 3D Holey Graphene Cathode Implanted with Single Iron Atoms

A highly efficient cathode catalyst for rechargeable Li-CO 2 batteries is successfully synthesized by implanting single iron atoms into 3D porous carbon architectures, consisting of interconnected N,S-codoped holey graphene (HG) sheets. The unique porous 3D hierarchical architecture of the catalyst with a large surface area and sufficient space within the interconnected HG framework can not only facilitate electron transport and CO 2 /Li+ diffusion, but also allow for a high uptake of Li 2 CO 3 to ensure a high capacity. Consequently, the resultant rechargeable Li-CO 2 batteries exhibit a low potential gap of approximate to 1.17 V at 100 mA g -1 and can be repeatedly charged and discharged for over 200 cycles with a cut-off capacity of 1000 mAh g -1 at a high current density of 1 A g -1 . Density functional theory calculations are performed and the observed appealing catalytic performance is correlated with the hierarchical structure of the carbon catalyst. This work provides an effective approach to the development of highly efficient cathode catalysts for metal-CO 2 batteries and beyond.

(2) batteries↗
DOE OSTI2021

Enhanced Catalysis under 2D Silica: A CO Oxidation Study

Interfacially confined microenvironments have recently gained attention in catalysis, as they can be used to modulate reaction chemistry. The emergence of a 2D nanospace at the interface between a 2D material and its support can promote varying kinetic and energetic schemes based on molecular level confinement effects imposed in this reduced volume. We report on the use of a 2D oxide cover, bilayer silica, on catalytically active Pd(111) undergoing the CO oxidation reaction. We “uncover” mechanistic insights about the structure-activity relationship with and without a 2D silica overlayer using in situ IR and X-ray spectroscopy and mass spectrometry methods. We find that the CO oxidation reaction on Pd(111) benefits from confinement effects imposed on surface adsorbates under 2D silica. Finally, this interaction results in a lower and more dispersed coverage of CO adsorbates with restricted CO adsorption geometries, which promote oxygen adsorption and lay the foundation for the formation of a reactive surface oxide that produces higher CO 2 formation rates than Pd alone.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Photochemically-Driven CO 2 Release Using a Metastable-State Photoacid for Energy Efficient Direct Air Capture

One of the grand challenges underlying current direct air capture (DAC) technologies relates to the intensive energy cost for sorbent regeneration and CO 2 release, making the massive scale (GtCO 2 /year) deployment required to have a positive impact on climate change economically unfeasible. This challenge underscores the critical need to develop new DAC processes with substantially reduced regeneration energies. Here, in this work, we report a photochemically-driven approach for CO 2 release by exploiting the unique properties of an indazole metastable-state photoacid (mPAH). Our measurements on simulated and amino acid-based DAC systems revealed the potential of mPAH to be used for CO 2 release cycles by regulating pH changes and associated isomers driven by light. Upon irradiating with moderate intensity light, a ≈55 % and ≈68 % to ≈78 % conversion of total inorganic carbon to CO 2 was found for the simulated and amino acid-based DAC systems, respectively. Our results confirm the feasibility of on-demand CO 2 release under ambient conditions using light instead of heat, thereby providing an energy efficient pathway for the regeneration of DAC sorbents.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Mechanisms in the Synthesis of S -Alcohols with 1,4-NADH Biomimetic Co-factor N-Benzyl-1,4-dihydronicotinamide using Horse Liver Alcohol Dehydrogenase: A Hybrid Computational Study

The enantioselective reduction of prochiral ketones catalyzed by horse liver alcohol dehydrogenase (HLADH), was investigated via a hybrid computational approach, for molecular reactions involved in chiral synthesis of S-alcohols, when the natural co-factor, 1,4-dihyronicotinamide adenine dinucleotide, 1,4-NADH, was replaced with biomimetic co-factor, N-benzyl-1,4-dihydronicotinamide, 1. We surmised that different hydride and proton transfer mechanisms were involved using co-factor, 1. An alternative mechanism, where the hydride transfer step occurred, via an η 1 -keto-S-η 2 -5,6-1,4-dihydronicotinamide-Zn(II) complex, was previously investigated with a model of the HLADH-Zn(II) catalytic site (J. Organometal. Chem. 2021, 943, 121810). Presently, we studied canonical and alternative mechanisms compared to models of the entire enzyme structure. We disproved the η 2 -Zn(II) complex, and discovered a canonical hydride transfer from biomimetic 1,4-NADH, 1, to the Zn(II) bound prochiral ketone substrate, followed by a new proton relay, consisting of a water chain connecting His51 to Ser48 that accomplished the S-alkoxy anion's protonation to yield the final S-alcohol product. The HLADH catalysis, with biomimetic co-factor, 1, that replaced the ribose group, the 5'-diphosphate groups, and the adenine nucleotide with a N-benzyl group, has provided a new paradigm for the design of other structures of 1,4-NADH biomimetic co-factors, including their economic value in biocatalysis reactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

PdCu Alloy Catalyst for Inhibition‐free, Low‐temperature CO Oxidation

Designing robust catalysts for low‐temperature oxidation is pertinent to the development of advanced combustion engines to meet increasingly stringent emissions limitations. Oxidation of CO, hydrocarbon, and NO pollutants over platinum‐group catalysts suffer from strong inhibition due to their competitive adsorption, while coinage metals are generally slow at activating O 2 . Through computational screening, we discovered a PdCu alloy catalyst that completely oxidizes CO below 150 °C without inhibition by NO, propylene or water. This is attributed primarily to geometric effects and the presence of CO bound to Pd sites within the Cu‐rich surface of the PdCu alloy. Here, we demonstrate that the novel PdCu catalyst can be used in tandem with a PtPd catalyst to achieve sequential, inhibition‐free, complete oxidation of CO in a two‐bed system, while also achieving 50 % NO conversion below 120 °C. Moreover, neither water nor propylene adversely affect the low temperature CO oxidation activity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Pt Nanoparticle Disintegration at Oxide Interfaces Enhances CO Oxidation Catalysis

Understanding how supported metal nanoparticles dynamically evolve under reaction conditions is critical for controlling their catalytic function. Here, the mechanism behind the dynamic disintegration of Pt nanoparticles (NPs) supported on CeOx-TiO2 (CT) during CO oxidation is elucidated, leading to the formation of single atoms (SAs) and/or sub-nanometer clusters. Density functional theory (DFT) calculations reveal that strong Pt-CO interactions weaken Pt─Pt cohesion, while electronic coupling between Pt and Ce ions stabilizes Pt-CO* intermediates at the oxide interface. Surface oxygen vacancies kinetically trap Pt-CO*, but the vacancies are replenished under oxygen-rich conditions, enabling Pt-CO* surface diffusion and subsequent structural reorganization. In situ spectroscopic analyses confirm the oxygen-driven transformation of Pt NPs, correlating with a threefold increase in mass-specific activity at 150 °C. These findings demonstrate that interfacial oxygen dynamics and metal-support interactions can be leveraged to induce nanoparticle disintegration and optimize catalytic performance, highlighting the catalytic potential of interface-engineered Pt nanostructures.

CO oxidation↗
DOE OSTI2025

Initiation of dusting corrosion in high-temperature alloys under CO exposure

Carbon monoxide is commonly encountered in energy systems, yet its reactivity with structural alloys—critical heat-resistant components in these systems—has been largely overlooked compared to the well-documented effects of oxidizing gases. In contrast, we demonstrate the high-temperature reaction of CO with NiAl using in-situ low-energy electron microscopy and X-ray photoemission electron microscopy. Our results show that CO dissociates into atomic oxygen and carbon, resulting in two concurrent reactions: selective oxidation of aluminum to form Al 2 O 3 and the initiation of dusting corrosion through carbon dissolution into the alloy and subsequent carbon deposition on the surface. These reactions produce spatially distinct surface products, preventing the formation of a continuous protective Al oxide layer. These results reveal a preference for the dissociative pathway of CO over the classic Boudouard disproportionation reaction that forms CO 2 . These insights not only advance our understanding of CO-induced alloy degradation but also highlight the practical implications for managing alloy stability and optimizing catalysis in carbon-rich environments, such as those in petrochemical processing and hydrocarbon combustion.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Toward efficient single-atom catalysts for renewable fuels and chemicals production from biomass and CO 2

Transformation of biomass and CO 2 into renewable value-added chemicals and fuels has been identified as a promising strategy to fulfill high energy demands, lower greenhouse gas emissions, and exploit under-utilized resources. Cost-effective and performance-efficient catalysts are of great importance to lowering the conversion cost of biomass and CO 2 . Significant progress has been made to advance the catalyst design for these processes, with metal catalysts playing a critical role in many involved catalytic reactions. Traditional nanoparticle-based metal catalysts still require improvement in metal utilization rates, stability, and selectivity tunability. Single-atom catalysts, which have maximum atomic efficiency and a uniform and tunable metal center, as well as an adjustable metal-support interaction, provide potential opportunities to boost catalyst efficiency and thermal stability. Their well-defined and uniform structure also provides advantages to fundamental studies for understanding of the intrinsic reaction mechanism and site requirement in biomass and CO 2 conversion. In this article, we summarize and highlight the recent advances in converting biomass and CO 2 to renewable fuels and chemicals using single-atom catalysts. We discuss the design principles of single-atom catalysts and their potential applications to biomass and CO 2 upgrading as well as the origins of catalytic activity. Moreover, we compare the catalytic efficiency of various catalysts reported thus to provide a fair assessment of these catalysts. Finally, perspectives are given on the interesting fields that may guide future studies.

09 BIOMASS FUELS↗
DOE OSTI2022

Application of Box-Behnken design in optimizing product properties of supercritical methanol co -liquefaction of rice straw and linear low-density polyethylene

We report co-processing of plastic and biomass wastes to produce high-quality fuel has been attracting considerable interest in energy recovery. This work employed Box-Behnken Design (BBD) to optimize yield and properties of oil from supercritical methanol (scMeOH) co-liquefaction of rice straw (RS) and linear low-density polyethylene (LLDPE). Three independent variables of reaction temperature (270, 300, and 330°C), holding time (60, 90, and 120 mins), and RS/LLDPE mass ratio (0.15, 0.50, and 0.85) were selected for experiments. A maximum oil yield of 34.17 wt% was achieved at 303°C, 96 mins, and RS/LLDPE ratio of 0.59 according to BBD. Temperature and RS/LLDPE ratio dominated the oil yield and synergistic effects during co-liquefaction, whereas time was an insignificant factor. Optimum oil from co-liquefaction contained substantial hydrocarbons content of 32.91% compared to that from single RS-derived oil of 7.77%. Solid product obtained at the optimum condition could be used as solid fuel, due to its relatively high HHV of 43.08 MJ/kg compared to the other solid fuels (13.90–32.14 MJ/kg). This work provides a deep understanding of the co-processing of solid biomass and plastic wastes.

09 BIOMASS FUELS↗