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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 865 records · Page 48
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Graphene prepared by thermal reduction–exfoliation of graphite oxide: Effect of raw graphite particle size on the properties of graphite oxide and graphene

Highlights: • Effect of raw graphite particle size on properties of GO and graphene is reported. • Size of raw graphite affects oxidation degree and chemical structure of GO. • Highly oxidized GO results in small-sized but well-exfoliated graphene. • GO properties affect reduction degree, structure, and conductivity of graphene. - Abstract: We report the effect of raw graphite size on the properties of graphite oxide and graphene prepared by thermal reduction–exfoliation of graphite oxide. Transmission electron microscope analysis shows that the lateral size of graphene becomes smaller when smaller size graphite is used. X-ray diffraction analysis confirms that graphite with smaller size is more effectively oxidized, resulting in a more effective subsequent exfoliation of the obtained graphite oxide toward graphene. X-ray photoelectron spectroscopy demonstrates that reduction of the graphite oxide derived from smaller size graphite into graphene is more efficient. However, Raman analysis suggests that the average size of the in-plane sp{sup 2}-carbon domains on graphene is smaller when smaller size graphite is used. The enhanced reduction degree and the reduced size of sp{sup 2}-carbon domains contribute contradictively to the electrical conductivity of graphene when the particle size of raw graphite reduces.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2024

Preparation of ultrathin sputtered gold films on palladium as efficient oxygen reduction electro-catalysts

Herein, we present the preparation of ultrathin gold (Au) films on different M (M = Pd, Pt, Rh, Ir, and Ru) electrodes (Au/M) using magnetron sputtering deposition for oxygen reduction reaction (ORR). The ORR electro-catalytic activities of prepared Au/M catalysts increase as follows: Au/Ru < Au/Ir < Au/Rh < Au/Pt < Au/Pd. Accordingly, the oxygen reduction catalytic behaviors of the Au-modified palladium (Au/Pd) thin films with various Au thicknesses (0.16, 0.24, 0.5, and 1 nm) are investigated in acidic environments. It is found that Au modifications can promote oxygen reduction performances due to the development of more catalytic active sites on the Pd catalyst through the existence of Au atoms. Noticeably, Au/Pd samples exhibit a connection in oxygen reduction ability as a function of Au thickness, with the ultrathin 0.16 nm Au/Pd being the most active ORR catalyst. Significantly, the 0.16 nm Au/Pd material demonstrates superior stability after 1000 potential cycles compared with the 0.16 nm Pt/Pd owing to the influence of Au coating and structurally stable surfaces. Therefore, surface modification with the deposition of Au films on Pd represents a favorable technique to boost both the ORR capability and stability of the electro-catalysts.

Magnetron sputtering↗
DOE OSTI2018

Nitrogen and sulfur co-doped porous carbon sheets for energy storage and pH-universal oxygen reduction reaction

Developing efficient electrocatalysts for energy storage and oxygen reduction reaction (ORR) is of great sig-nificance for the utilization of renewable energy. In particular, designing catalysts with both promising activityand long stability for ORR in pH-universal electrolytes still remain as a tremendous challenge. To tackle such aproblem, metal-free nitrogen and sulfur co-doped porous carbon sheet (NSPCS) was rationally designed in thiswork in order to integrate the two reported routes of enhancing the electrocatalytic activity of graphene. The as-prepared NSPCS has an onset potential of 0.89 V vs. RHE, and half-wave potential E1/2 ≈ 0.75 V during ORR inacidic solution, making it as the most active ORR catalyst. Moreover, the resulting NSPCS also shows a 0.03 Vpositive shift of half-wave potential than commercial Pt/C for ORR and excellent charge capacitive performancein alkaline media. Electron microscopy revealed high degree of defects on NSPCS surface. This, coupled withsynergistic doping effects of nitrogen and sulfur, optimized the active sites and charge transfer, rationalized theoutstanding performance in both oxygen reduction reactions and supercapacitors.Developing efficient electrocatalysts for energy storage and oxygen reduction reaction (ORR) is of great significance for the utilization of renewable energy. In particular, designing catalysts with both promising activity and long stability for ORR in pH-universal electrolytes still remain as a tremendous challenge. To tackle such a problem, metal-free nitrogen and sulfur co-doped porous carbon sheet (NSPCS) was rationally designed in this work in order to integrate the two reported routes of enhancing the electrocatalytic activity of graphene. The as-prepared NSPCS has an onset potential of 0.89 V vs. RHE, and half-wave potential E-1/2 approximate to 0.75 V during ORR in acidic solution, making it as the most active ORR catalyst. Moreover, the resulting NSPCS also shows a 0.03 V positive shift of half-wave potential than commercial Pt/C for ORR and excellent charge capacitive performance in alkaline media. Electron microscopy revealed high degree of defects on NSPCS surface. This, coupled with synergistic doping effects of nitrogen and sulfur, optimized the active sites and charge transfer, rationalized the outstanding performance in both oxygen reduction reactions and supercapacitors.

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

Reduction kinetics of hematite powder using argon/hydrogen plasma with prospects for near net shaping of sustainable iron

Direct reduction of iron ore using hydrogen plasma is being explored as a potential solution to decarbonize the iron and steel sector. The current state-of-the-art demonstrated reduction of hematite pellets via hydrogen plasma using Ar + 10% H 2 but had slow reduction kinetics, requiring 30 minutes of plasma exposure for complete reduction. Here we show that using hematite in a powder form, easily obtainable from beneficiated ore, results in 10× faster kinetics using plasma generated from Ar + 2% H 2 shielding gas compared to the current state-of-the art. Additionally, the increased kinetics using powders and a dilute hydrogen concentration can enable the use of advanced manufacturing techniques like blown powder directed energy deposition using a plasma tungsten arc welding torch to manufacture near net shape components directly from the ore concentrates. This ore to part approach will also reduce the emissions associated with downstream processes like rolling, forging, and machining, thereby further aiding in the sectorial decarbonization efforts.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Sonochemical reduction of Cr(VI) in air in the presence of organic additives: What are the involved mechanistic pathways?

In this research, the sonochemical (850 kHz) reduction of Cr(VI) (0.3 mM, pH 2, reactor open to air) was analyzed in the presence of different additives. The effects on Cr(VI) reduction efficiency of added formic acid (FA, 10 mM), citric acid (Cit, 2 mM), ethylenediaminetetraacetic acid (EDTA, 1 mM), methanol (MeOH, 0.1 M), ethanol (EtOH, 0.1 M), 2-propanol (2-PrOH, 0.1 M), tert -butanol ( t -BuOH, 0.1 M), phenol (PhOH, 2 mM) and sodium lauryl sulfate (SLS, 1 mM) have been evaluated in comparison with the system in the absence of additives. Complete Cr(VI) reduction was obtained only when using EDTA (at 120 min) and Cit (at 180 min). Cr(III) complexes with these compounds or with their degradation products were detected as final products. For EDTA, Cit, t -BuOH, FA and SLS, the Cr(VI) decay could be adjusted to a zero-order kinetics; in the cases of MeOH, EtOH and 2-PrOH, there was a deviation from the zero-order kinetics. The Cr(VI) conversion increased in the order SLS (very low) < no additive ≅ MeOH ≅ EtOH ≅ 2-PrOH < FA < t -BuOH < PhOH < Cit < EDTA. The role of EDTA and Cit in stabilizing intermediate Cr(V) peroxo compounds and enhancing their direct transformation into different Cr(III) species is considered a major factor in the acceleration of Cr(VI) reduction processes. Mechanistic pathways are proposed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Interface reduction for Hurty/Craig-Bampton substructured models: Review and improvements

The Hurty/Craig-Bampton method in structural dynamics represents the interior dynamics of each subcomponent in a substructured system with a truncated set of normal modes and retains all of the physical degrees of freedom at the substructure interfaces. This makes the assembly of substructures into a reduced-order system model relatively simple, but means that the reduced-order assembly will have as many interface degrees of freedom as the full model. When the full-model mesh is highly refined, and/or when the system is divided into many subcomponents, this can lead to an unacceptably large system of equations of motion. To overcome this, interface reduction methods aim to reduce the size of the Hurty/Craig-Bampton model by reducing the number of interface degrees of freedom. This research presents a survey of interface reduction methods for Hurty/Craig-Bampton models, and proposes improvements and generalizations to some of the methods. Some of these interface reductions operate on the assembled system-level matrices while others perform reduction locally by considering the uncoupled substructures. The advantages and disadvantages of these methods are highlighted and assessed through comparisons of results obtained from a variety of representative linear FE models.

42 ENGINEERING↗
DOE OSTI2021

Revealing High-Temperature Reduction Dynamics of High-Entropy Alloy Nanoparticles via In Situ Transmission Electron Microscopy

Understanding the behavior of high-entropy alloy (HEA) materials under hydrogen (H 2 ) environment is of utmost importance for their promising applications in structural materials, catalysis, and energy-related reactions. Herein, the reduction behavior of oxidized FeCoNiCuPt HEA nanoparticles (NPs) in atmospheric pressure H-2 environment was investigated by in situ gas-cell transmission electron microscopy (TEM). The reduction reaction front was maintained at the external surface of the oxide. During reduction, the oxide layer expanded and transformed into porous structures where oxidized Cu was fully reduced to Cu NPs while Fe, Co, and Ni remained in the oxidized form. In situ chemical analysis showed that the expansion of the oxide layer resulted from the outward diffusion flux of all transition metals (Fe, Co, Ni, Cu). Revealing the H-2 reduction behavior of HEA NPs facilitates the development of advanced multicomponent alloys for applications targeting H 2 formation and storage, catalytic hydrogenation, and corrosion removal.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2026

Unraveling Defect-Dependent Conductivity-Type Switching in CuFe 2 O 4 for Enhanced Photoelectrocatalytic Reduction of Benzaldehyde

Photoelectrocatalytic (PEC) reduction provides a sustainable route for upgrading biomass-derived feedstocks with reduced energy requirements, yet remains largely unexplored beyond hydrogen evolution and CO 2 reduction due to the scarcity of stable photocathodes. Here, we report a defect-engineered CuFe 2 O 4 photocathode that enables directly quantified PEC reduction of benzaldehyde to benzyl alcohol using a singlecomponent, earth-abundant oxide. By controlling annealing temperature and oxygen partial pressure, CuFe 2 O 4 is systematically tuned from n-type to p-type conductivity. Electrochemical measurements, X-ray and ultraviolet photoelectron spectroscopy, and firstprinciples defect calculations collectively show that oxygen-rich annealing conditions suppress deep donor-type oxygen vacancies while stabilizing shallow acceptor-type copper vacancies, resulting in enhanced hole concentration and improved charge transport. In a mixed acetonitrile/water electrolyte employing 1,4-benzoquinone as a redox mediator, the optimized CuFe 2 O 4 photocathode achieves stable photoelectrochemical operation over 18 h under continuous illumination with a benzyl alcohol production rate of 2.57 μmol/h at −0.50 V vs Ag/AgNO 3 , corresponding to a Faradaic efficiency of 51.3%. This PEC approach lowers the required applied potential by ∼1 V compared to traditional electrocatalytic methods, offering a more energy-efficient route for carbonyl reduction. These findings establish CuFe 2 O 4 as a viable photocathode platform for sustainable photoelectrocatalytic organic transformations under mild reaction conditions.

benzaldehyde reduction↗
DOE OSTI2022

Role of Bimetallic Interactions in the Enhancement of Catalytic CO 2 Reduction by a Macrocyclic Cobalt Catalyst

The use of two metal centers in a CO 2 reduction catalyst that work together synergistically, with similar or complementary functions, can potentially lead to a significant reduction in overpotential, enhance catalytic activity and/or selectivity, and/or enable access to cascade strategies where each metal center catalyzes a different step in the conversion of CO 2 to a fuel. Here, the bimetallic reactivity of two metal centers has been identified as the primary route for the reduction of CO 2 to CO promoted by the macrocycle, [Co(HMD)] 2+ (HMD = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene), based on the experimental characterization of all major steps of the proposed catalytic cycle using pulse radiolysis time-resolved IR (PR-TRIR) spectroscopy, corroborated by density functional theory (DFT) calculations and IR spectroelectrochemistry (IR-SEC). A bimetallic intermediate is formed in situ from two singly reduced [Co(HMD)] + species bridged by a CO 2 molecule, and the presence of a coordinating species, e.g., formate anion, appears to assist in the formation of such an intermediate. In this work, it has been demonstrated that this reactivity enables access to elementary steps with lower energy requirements, resulting in overall catalysis being kinetically more facile compared to the mononuclear pathway. A two-step approach that combines chemical reduction followed by PR-TRIR has been successfully used for probing the structure and reactivity of reactive intermediates involved in the advanced stages of a catalytic cycle, which are rarely interrogated using experimental techniques.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Exchange Coupling Determines Metal-Dependent Efficiency for Iron- and Cobalt-Catalyzed Photochemical CO 2 Reduction

Catalysts promoting multielectron charge delocalization offer selectivity for the CO 2 reduction reaction (CO 2 RR) over the competing hydrogen evolution reaction. Here, we show metal–ligand exchange coupling as an example of charge delocalization that can determine the efficiency for photocatalytic CO 2 RR. A comparative evaluation of iron and cobalt complexes supported by the redox-active ligand tpyPY2Me establishes that the two-electron reduction of [Co(tpyPY2Me)] 2+ ([Co] 2+ ) occurs at potentials 770 mV more negative than the [Fe(tpyPY2Me)] 2+ ([Fe] 2+ ) analogue by maximizing the exchange coupling in the latter compound. The positive shift in the reduction potential promoted by metal–ligand exchange coupling drives [Fe] 2+ to be among the most active and selective molecular catalysts for photochemical CO 2 RR reported to date, maintaining up to 99% CO product selectivity with total turnover numbers (TONs) and initial turnover frequencies exceeding 30,000 and 900 min –1 , respectively. In contrast, [Co] 2+ shows much lower CO 2 RR activity, reaching only ca. 600 TON at 83% CO product selectivity under similar conditions accompanied by rapid catalyst decomposition. Further, the spin density plots of the two-electron reduced [Co] 0 complex implicate a paramagnetic open-shell doublet ground state compared to the diamagnetic open-shell singlet ground state of reduced [Fe] 0 , rationalizing the observed negative shift in two-electron reduction potentials from the [M] 2+ species and lowered CO 2 RR efficiency for the cobalt complex relative to its iron congener. This work emphasizes the contributions of multielectron metal–ligand exchange coupling in promoting effective CO 2 RR and provides a starting point for the broader incorporation of this strategy in catalyst design.

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

Controlling Product Selectivity in Photochemical CO 2 Reduction with the Redox Potential of the Photosensitizer

The ability to selectively reduce CO 2 to a particular product or mixture of products is expected to play a key role in mitigation strategies aiming to alleviate the devastating impact of this greenhouse gas in our climate and oceans. Among those, the production of liquid solar fuels from CO 2 and H 2 O will likely need cascade strategies involving multiple catalysts carrying out different functions. This will require that the catalysts doing the initial CO 2 reduction steps deliver the right product or products to downstream catalysts. CO, H 2 and formate are the most common products in CO 2 reduction by molecular catalysts. Here, in this work, we demonstrate control over the selectivity of C 1 products in photochemical CO 2 reduction with the same catalyst, simply by changing the redox potential of the photosensitizer and/or the water concentration. Turnover numbers for CO generation with one of the photosensitizers under anhydrous conditions reached 85,000, one of the largest values reported to date. A combination of experimental results and DFT calculations show that control of the selectivity is achieved, in part, due to the interplay between regimes under kinetic or thermodynamic control. These regimes are largely dictated by the proton sources and the CO 2 reduction byproducts generated.

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

Catalytic Oxygen Reduction for Deep O 2 Removal from CO 2 Streams

Streams of CO 2 from various capture processes may contain several impurities of which O 2 is often overlooked as a problematic impurity. Because of its reactivity, the National Energy Technology Laboratory has recommended a stringent limit, less than 10 ppm, for the O 2 level in treated CO 2 products for safe transport, storage, and utilization. Here, in this study, a variety of catalytic oxygen reduction approaches using commercial automotive exhaust emission catalysts are evaluated for O 2 removal from CO 2 streams using different reducing agents, including H 2 , CO, CH 3 OH, and CH 4 . When the amount of reductant added into the feed is carefully controlled, H 2 , CO, or CH 3 OH can effectively remove O 2 from 1.5% to below 10 ppm with a single-reactor design (>99.93% removal efficiency), while simultaneously meeting the impurity limits for other species. With CH 4 as a reductant, it is challenging to simultaneously meet the the O 2 and CO specifications in a single-reactor design because CH 4 also reacts with CO 2 to produce high levels of CO in the stream (at several hundred ppm). A dual-reactor design is developed to enable the use of CH 4 , a readily available and low-cost reductant, for the purification of CO 2 streams to meet the specifications for O 2 and other impurities.

CO2 purification↗
DOE OSTI2020

Metal–Ligand Cooperativity via Exchange Coupling Promotes Iron- Catalyzed Electrochemical CO 2 Reduction at Low Overpotentials

Biological and heterogeneous catalysts for the electrochemical CO 2 reduction reaction (CO 2 RR) often exhibit a high degree of electronic delocalization that serves to minimize overpotential and maximize selectivity over the hydrogen evolution reaction (HER). Here, we report a molecular iron(II) system that captures this design concept in a homogeneous setting through the use of a redox non-innocent terpyridine-based pentapyridine ligand (tpyPY2Me). As a result of strong metal-ligand exchange coupling between the Fe(II) center and ligand, [Fe(tpyPY2Me)] 2+ exhibits redox behavior at potentials 640 mV more positive than the isostructural [Zn(tpyPY2Me)] 2+ analog containing the redox-inactive Zn(II) ion. This shift in redox potential is attributed to the requirement for both an open-shell metal ion and a redox non-innocent ligand. The metal-ligand cooperativity in [Fe(tpyPY2Me)] 2+ drives the electrochemical reduction of CO 2 to CO at low overpotentials with high selectivity for CO 2 RR (>90%) and turnover frequencies of 100,000 s -1 with no degradation over 20 h. The decrease in the thermodynamic barrier engendered by this coupling also enables homogeneous CO 2 reduction catalysis in water without compromising selectivity or rates. Synthesis of the two-electron reduction product, [Fe(tpyPY2Me)] o , and characterization by X-ray crystallography, Mössbauer spectroscopy, X-ray absorption spectroscopy (XAS), variable temperature NMR, and density functional theory (DFT) calculations, support assignment of an open-shell singlet electronic structure that maintains a formal Fe(II) oxidation state with a doubly reduced ligand system. Furthermore, this work provides a starting point for the design of systems that exploit metal-ligand cooperativity for electrocatalysis where the electrochemical potential of redox non-innocent ligands can be tuned through secondary metal-dependent interactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Bridge Sites of Au Surfaces Are Active for Electrocatalytic CO 2 Reduction

Prior in-situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) studies of electrochemical CO 2 reduction catalyzed by Au, one of the most selective and active electrocatalysts to produce CO from CO 2 , suggest that the reaction proceeds solely on the top sites of the Au surface. This finding is worth updating with an improved spectroelectrochemical system where in-situ IR measurements can be performed under real reaction conditions that yield high CO selectivity. Herein, we report the preparation of a Au-coated Si ATR crystal electrode with both high catalytic activity for CO 2 reduction and strong surface enhancement of IR signals validated in the same spectroelectrochemical cell, which allows us to probe the adsorption and desorption behavior of bridge-bonded *CO species (*CO B ). In this study we find that the Au surface restructures irreversibly to give an increased number of bridge sites for CO adsorption within the initial tens of seconds of CO 2 reduction. By studying the potential-dependent desorption kinetics of *CO B and quantifying the steady-state surface concentration of *CO B under reaction conditions, we further show that *CO B are active reaction intermediates for CO 2 reduction to CO on the Au surface. At medium overpotential, as high as 38% of the reaction occurs on the bridge sites.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Promoter Effects of Alkali Metal Cations on the Electrochemical Reduction of Carbon Dioxide

The electrochemical reduction of CO 2 is known to be influenced by the identity of the alkali metal cation in the electrolyte; however, a satisfactory explanation for this phenomenon has not been developed. Here we present the results of experimental and theoretical studies aimed at elucidating the effects of electrolyte cation size on the intrinsic activity and selectivity of metal catalysts for the reduction of CO 2 . Experiments were conducted under conditions where the influence of electrolyte polarization is minimal in order to show that cation size affects the intrinsic rates of formation of certain reaction products, most notably for HCOO – , C 2 H 4 , and C 2 H 5 OH over Cu(100)- and Cu(111)-oriented thin films, and for CO and HCOO– over polycrystalline Ag and Sn. Interpretation of the findings for CO 2 reduction was informed by studies of the reduction of glyoxal and CO, key intermediates along the reaction pathway to final products. Density functional theory calculations show that the alkali metal cations influence the distribution of products formed as a consequence of electrostatic interactions between solvated cations present at the outer Helmholtz plane and adsorbed species having large dipole moments. As a result, the observed trends in activity with cation size are attributed to an increase in the concentration of cations at the outer Helmholtz plane with increasing cation size.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Widespread Wildfires Over the Western United States in 2020 Linked to Emissions Reductions During COVID-19

Widespread wildfires struck western United States in 2020, directly damaging properties and threatening human lives. Meanwhile, the COVID-19 pandemic rapidly spread across the globe in 2020, which disrupted human activities and resulted in substantial reductions in anthropogenic emissions. Here, we investigate the effects of the emissions reductions of aerosols, precursors, and greenhouse gases during the pandemic on wildfire weather conditions in 2020 over western United States by using an earth system model together with observational data. We show that the COVID-19 emissions reductions in model experiments increased surface air temperature and decreased precipitation and relative humidity due to a weakened moisture transport, which explains 10-40% of the observed increase in the risk of wildfires over western United States in 2020. In conclusion, this study suggests that COVID-19-related abrupt emissions reductions have an unexpected influence on wildfires, highlighting a different but important role of human activities in affecting wildfire risks.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

The oxygen reduction reaction catalyzed by Synechocystis sp. PCC 6803 flavodiiron proteins

Photosynthetic flavodiiron (Flv) proteins bind flavin and non-heme Fe cofactors and catalyze the oxygen reduction reaction (ORR) coupled to oxidation of reduced pyridine nucleotides during photosynthetic growth. The activity of Flvs have also been observed to form an important catalytic redox loop with water oxidation necessary for preserving photosynthetic electron transport function in cyanobacteria. To determine how these functions may be related, we investigated the kinetic properties of Flv1 and Flv3 from Synechocystis sp. PCC 6803. Under an oxygen atmosphere, Flv1 and Flv3 were found to catalyze ORR with either NADH or NADPH as the electron donor. Reaction velocity curves were sigmoidal and Flv binding of NAD(P)H was cooperative. Based on mass spectrometry generated structural models, each Flv assembles as a homodimer with two oxidoreductase domains capable of binding two molecules of NAD(P)H per subunit, and the flavins are arranged to support electron transfer to the diiron sites for oxygen reduction. Titrations with NAD(P)H resulted in reduction of the diiron site without the accumulation of stable, reduced flavin intermediates. Altogether, the results provide new insights on the properties of Flv1 and Flv3 that enable tight control of reactivity for the complete reduction of oxygen to water, and in this capacity help preserve photosynthetic electron transport function.

09 BIOMASS FUELS↗
DOE OSTI2024

Radiation-assisted electrochemical reduction of CO 2 to CO

Carbon monoxide (CO) is a versatile intermediate feedstock for many applications and can be produced through the electrochemical reduction of carbon dioxide (CO 2 ). However, current electrochemical CO production is hindered by high overall costs, primarily due to low conversion efficiencies and significant energy requirements. Herein, we report a unique way of enhancing the electrochemical reduction of CO 2 to CO using gamma (γ) photons. The γ-irradiation applied to the electrochemical cell setup induces the production of e˙ - , which results in an increased CO 2 ionization and production of excited CO 2 (CO$^{*}_{2}$) molecules via lower energy barrier. The ionized CO 2 ˙ - is quickly stabilized over a silver catalyst, providing an alternative low activation energy route for CO 2 reduction. In conclusion, a decrease in the overpotential barrier enhanced the electrochemical reduction of CO 2 to CO by 25%.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗