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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Enhanced low temperature performance of bimetallic Pd/Pt/SiO 2 (core)@Zr(shell) diesel oxidation catalysts

Here, in this study, the diesel oxidation performance of degreened (DG) and hydrothermally aged monometallic and bimetallic Pd/Pt/SiO 2 (core)@Zr(shell) catalysts with varying Pd/Pt molar ratios from 3/1–1/3 was evaluated. Pd/Pt(3/1)/SiO 2 @Zr (DG) achieved 50% and 90% conversion of CO at 166 °C (T 50 ), 169 °C (T 90 ) and total hydrocarbons (THCs) at 198 °C (T 50 ), 244 °C (T 90 ). Decreasing the Pd/Pt molar ratio led to a decrease in the T 50,90 ’s, with Pd/Pt(1/3)/SiO 2 @Zr (DG) achieving T 50,90 ’s at 153, 156 °C for CO and 171, 200 °C for THCs, respectively. Moreover, Pd/Pt(1/3)/SiO 2 @Zr showed enhanced hydrothermal stability. XRD and TEM showed that in the hydrothermally aged bimetallic catalysts, the fraction of Pd present as a Pt-Pd metallic alloy increased with Pt content. The enhanced low temperature performance of Pd/Pt(1/3)/SiO 2 @Zr compared to the other studied catalysts was attributed to Pd being primarily present in metallic form, despite being subjected to severe oxidizing conditions.

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

Understanding the Origin of Negative Temperature Dependence and Activity of N-Coordinated Cobalt Sites During Ethylene Dimerization

The on-demand production of short-chain linear alpha olefins (LAOs; C4-C8) via C2H4 dimerization and oligomerization is industrially attractive, prompting extensive research on designing active, selective, and stable catalysts for industrial use. Cobalt supported on ammoniated carbon (Co(NH3)x/C) catalysts have shown remarkable activity and selectivity in this process. However, critical aspects such as the active phase, active site structure, the role of the catalyst support, cobalt loading effects, and the inverse correlation of the reaction rate with temperature remain inadequately understood. This study systematically explores these factors using a combination of steady-state differential catalytic tests, in situ molecular characterization including diffuse reflectance UV-Vis (DR-UV-Vis), Infrared, and Raman spectroscopies, and ex situ X-ray diffraction (XRD) and high annular aberration-corrected dark field transmission electron microscopy (HAADF-STEM). Various supports (SiO2, Al2O3, NH4-ZSM-5, g-C3N4, and C) and cobalt loadings (1.0-3.0 Co nm-2) were studied to determine the optimal catalyst composition and identify the active phase and sites. Carbon-supported catalysts uniquely produce C4-8 LAOs during C2H4 dimerization, with site-time-yield remaining constant (~10-3 s-1) for 1.0-4.0 Co nm-2 at prolonged reaction times (24-48?h time-on-stream). At higher loadings of 6.0 Co nm-2, the formation of crystalline CoO and Co3O4 phases reduces catalytic activity and LAO selectivity. Our findings show that active catalysts lack crystalline cobalt oxides and instead feature dispersed Co2+ sites, tetra-coordinated to a mix of N/NH3 and O/H2O ligands, which catalyze C2H4 dimerization via the Cossee-Arlman mechanism, exhibiting 1st order dependence on C2H4 concentration. The observed inverse rate-temperature correlation is attributed to compensation effects (i.e., presence of Cremer-Constable relationship) linked to changes in adsorption enthalpic and entropic factors.

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

Promoting the oxidative coupling of methanol and dimethylamine using group 1 alkali metals on palladium-gold nanoparticles

PdAu/SiO 2 catalysts were synthesized by strong electrostatic adsorption (SEA) and characterized by TEM, DRIFTS, XRD, XAS, and O 2 -TPD. The use of group 1 alkali salt solutions to control pH during SEA syntheses led to uptake of alkali metals observed reductions in the densities of terminal silanol groups of the SiO 2 support. In the absence of alkali metals, PdAu/SiO 2 catalyzes oxidative C-N bond formation between methanol and dimethylamine (DMA), yielding dimethylformamide (DMF) with ∼95 % carbon selectivity (CO 2 ∼5 %) at temperatures below 413 K. When Na, K, and Cs were present on the catalyst, methyl formate (MF) and tetramethylurea (TMU) were observed as additional products (combined ∼30 % carbon selectivity) while only TMU was detected for the Li-promoted catalyst. Total coupling product rate increased for promoted samples in the order Li < Na < Cs < K, and the apparent kinetics over the Cs-promoted catalyst were distinct from those over the alkali-free catalyst as the apparent reaction order with respect to DMA decreased and the apparent activation energy increased. Finally, this work demonstrates the sensitivity of oxidative coupling reactions to alkali metal promoters and the opportunity to achieve alkali promotion of metal catalysts during SEA synthesis.

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

Elucidating the factors controlling the methanol synthesis from CO 2 on ZnPd-ZnO/TiO 2 catalysts prepared by direct/inverse impregnation

The direct hydrogenation of CO 2 to methanol over supported ZnPd intermetallic catalysts remains a challenge due to the complex nature of the active sites, which are highly dependent on both the dispersion of ZnPd intermetallics and their proximity to ZnO. This study investigates the effect of the Pd and Zn incorporation order on methanol synthesis over TiO 2 -supported ZnPd catalysts. Catalysts were prepared via direct (Pd/Zn), inverse (Zn/Pd), and co-impregnation (Pd+Zn) methods using anatase TiO 2 as the support. Comprehensive characterization by XRD, HRTEM, CO-DRIFTS and XPS revealed that the formation of small and crystalline intermetallic β-ZnPd particles and their interaction with ZnO/ZnO x depends on the sequence of Pd and Zn incorporation. It was found that, under the reaction conditions, the ZnO x species plays a critical role in facilitating the formation of the intermetallic ZnPd through the interactions between Pd and ZnO x . In addition, ZnO x species have also been shown to modulate key catalytic properties, such as CO 2 activation and methanol selectivity. Specifically, the ZnPd/Pd surface ratio, determined by Pd dispersion and proximity to ZnO/ZnO x , was shown to determine the methanol production from CO 2 directly or via a CO intermediate. The Pd/Zn catalyst showed superior selectivity due to the in-situ formation of intermetallic species facilitated by Pd-ZnO x interactions.

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

Role of Mg:Al ratio and Pt promotion on mitigating the deactivation of Ni-based methane steam reforming catalysts

Ni-based catalysts for CH 4 steam reforming require fine-tuning to withstand deactivation under dynamic operation conditions relevant to emerging H 2 -driven technologies. This study investigates the impact of the Mg:Al ratio and Pt presence in catalyst composition on the activity and stability of industrially relevant Ni-based mono- and bimetallic catalysts during simulated daily start-up and shut-down cycles in various gas atmospheres. The evolution of the catalyst structure during extensive testing procedures was investigated in detail by complementary electron microscopy, in situ/operando XAS and XRD. The results obtained revealed that catalyst deactivation is promoted at high Mg:Al ratios and especially affects the monometallic catalysts. By converting CH 4 at lower temperatures, Pt regulates the extent of Ni oxidation and its incorporation into MgO lattice. Further prevention of catalyst deactivation was achieved by optimizing the reactor shut-down procedure to minimize the simultaneous exposure to high temperatures and H 2 O vapors. By flushing the reactor with N 2 only around the reaction extinction temperature, a fraction of Ni species is maintained in metallic state, which is beneficial for the long-term activity and reaction operation economy.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Systematic investigations on iron cycling in phosphorus/siderophore systems: Synergism or antagonism?

Synergisms between microbial exudates on Fe (hydr)oxide dissolution as an effective Fe acquisition pathway have been recently addressed and vigorously debated. However, Fe liberation mechanisms and where siderophores and phosphorus (P) coexist received little attentions. Current study systematically investigated ferrihydrite dissolution in the presence of desferrioxamine B (DFOB) (a kind of fungally-derived siderophores) and inorganic/organic phosphorus (orthophosphate, Pi; myo-inositol hexaphosphate, IHP), as a function of solute pH, reaction time and reagent content. Reacted solids were characterized by N 2 -BET adsorption, zeta (ζ) potential analysis, sequential extraction analysis (SEDEX), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), micro Raman spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Our results indicate that upon reaction with P-only or (DFOB + P) systems, interfacial complexation partially switched from monolayer bidentate-binuclear surface complexes to ternary complexes, or laterally transformed into amorphous Fe–P precipitates. The Fe-Pi complex precipitated more readily under acidic conditions, and Fe-IHP complex preferentially nucleated in neutral-alkaline environments. Phosphorus slightly promoted Fe release from minerals and fixation to the leached layer or interfacial liquid zone initially, but subsequently prevented further attacks from protons and DFOB. The co-effects of P and DFOB likely correspond to two successive scenarios: 1) DFOB is preferentially attracted toward ferrihydrite surfaces by negative electrical fields induced by adsorbed phosphorus and can act synergistically with labile P–Fe complexes, resulting in intensive temporal dissolution of Fh; 2) subsequent Fe shuttling to DFOB can be prohibited by stabilized, passive P/Fe–P layers. Finally, our results emphasize the antagonism between P compounds and siderophores (i.e., DFOB here) on ferrihydrite dissolution to improve understanding of the biologically-mediated Fe cycling in natural systems.

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

Experimental and computational investigations on the SO 2 poisoning of (La 0.8 Sr 0.2 ) 0.95 MnO 3 cathode materials

To study the formation of detrimental phases under the sulfur gas impurity to the long-term degradation in the LSM cathode material, the classic cathode material, (La 0.8 Sr 0.2 ) 0.95 MnO 3 (LSM), was prepared, sintered, and annealed at 800, 900, and 1000°C in the sulfur-containing atmospheres, respectively. Through X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Transmission electron microscopy (TEM) techniques, as well as the CALPHAD (Computer Coupling of Phase Diagrams and Thermochemistry) methodology, the secondary phases, especially the detrimental ones, under different conditions were predicted and experimentally verified correspondingly. Furthermore, sulfur poisoning results indicate that the accelerated tests might have degradation mechanisms different from actual operation conditions. More importantly, comprehensive comparisons among various impurity-containing conditions were also made to recommend better operation parameters.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Interface structures of inclined ZnO thin film on (0 1 1)-MgO substrate with bulk-like optical properties

Combining different phase structure materials with unique properties to design novel devices plays a significant role in the development of modern electronics. Here, we explore the characteristics of this type of complex interface and epitaxy structures based on the coupling between hexagonal ZnO film and cubic MgO substrate. The ZnO film was prepared by the molecular beam epitaxy technique on the MgO (0 1 1) substrate. The analysis results from the in situ reflection high energy electron diffraction patterns, X-ray diffraction (XRD)-pole figures and high resolution transmission electron microscopy images demonstrate that the film exhibits two-fold symmetry domains with a growth direction deviated from c-axis at about 31º along the [0 1 0] MgO or [0 $\bar{1}$ 0] MgO azimuth. Despite the intertwined diffusion from Zn and Mg atoms in the interface, which is the possible origin of a blue shift of about 0.083 eV in the Photoluminescence (PL) spectrum, the inclined film shows a full width at half maximum value that is close to the reported value from the high quality film. Finally, this work hopefully provides useful insights to the design and exploration of the novel optoelectronic devices that involve the integration of materials with different structure and different properties.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2021

Investigation of GaAs surface treatments for ZnSe growth by molecular beam epitaxy without a buffer layer

Atomically clean and smooth surfaces are critical prerequisite for the epitaxial regrowth of dissimilar semiconductors. Using ZnSe/GaAs as a model system, epitaxial regrowth without a buffer layer after thermal cleaning with various As-fluxes, atomic Ga flux, and atomic hydrogen treatments to the GaAs substrates and the surfaces were investigated in this work via in-situ Auger electron spectroscopy (AES). The ZnSe epilayers grown on the pre-treated GaAs surfaces without a buffer layer were characterized by X-ray diffraction (XRD), photoluminescence (PL) and atomic force microscopy (AFM) to evaluate the effectiveness of the surface treatment methods. It was found that a high quality ZnSe layer can be achieved by atomic hydrogen surface treatment at 300°C without requiring GaAs buffer layer growth, which reveals a path for epitaxy growth avoiding high temperature treatments.

42 ENGINEERING↗
DOE OSTI2023

Overexpression of a gibberellin 20-oxidase gene in poplar xylem led to an increase in the size of nanocellulose fibrils and improved paper properties

Cellulose, the major component of secondary cell walls, is the most abundant renewable long-chain polymer on earth. Nanocellulose has become a prominent nano-reinforcement agent for polymer matrices in various industries. We report the generation of transgenic hybrid poplar overexpressing the Arabidopsis gibberellin 20-oxidase1 gene driven by a xylem-specific promoter to increase gibberellin (GA) biosynthesis in wood. X-ray diffraction (XRD) and sum frequency generation spectroscopic (SFG) analyses showed that cellulose in transgenic trees was less crystalline, but the crystal size was larger. The nanocellulose fibrils prepared from transgenic wood had an increased size compared to those from wild type. When such fibrils were used as a reinforcing agent in sheet paper preparation, the mechanical strength of the paper was significantly enhanced. Engineering the GA pathway can therefore affect nanocellulose properties, providing a new strategy for expanding nanocellulose applications.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Remarkable self-degradation of Cu/SAPO-34 selective catalytic reduction catalysts during storage at ambient conditions

A model Cu/SAPO-34 SCR catalyst with all Cu species maintained as isolated Cu(II) ions is synthesized herein. Following lengthy storage on the shelf under ambient conditions, this catalyst completely and irreversibly deactivates upon any heat treatments above ~100 °C. Via detailed characterizations with surface area/pore volume analysis, XRD, H 2 -TPR, and 27 Al, 29 Si and 31 P solid-state NMR, as well as continuous wave and pulsed EPR studies, it is concluded that over the course of storage, the SCR active sites [Cu(OH)] + and Brønsted acid sites ≡Si-O(H)-Al≡ are attacked by H 2 O molecules trapped in the SAPO-34 framework pores, and undergo hydrolysis to form copper hydroxide and terminal Al sites. Upon thermal treatment, these species interact with each other to form copper-aluminate-like species, leading to irreversible deactivation of this catalyst. This deactivation mechanism does not require or necessarily lead to extensive degradation (i.e., crystallinity loss) of the SAPO-34 support.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Dry reforming of methane over Ni supported on LaMnO 3 thin films

Thin films of LaMnO 3 were deposited onto MgAl 2 O 4 by Atomic Layer Deposition (ALD) and studied as supports for Ni in the Dry Reforming of Methane (DRM). Scanning Transmission Electron Microscopy (STEM) with Energy-Dispersive X-ray Spectroscopy (EDS) demonstrated that LaMnO 3 covered the support uniformly, and X-ray diffraction (XRD) showed that the LaMnO 3 films maintained their perovskite structure after 5 redox cycles at 1073 K. The Ni also remained well dispersed after 5 redox cycles at 1073 K. The LaMnO 3 -supported catalyst was more active than Ni on the unmodified MgAl 2 O 4 and showed superior resistance against coke formation. Lastly, the results for Ni on the LaMnO 3 films are compared to previous results for Ni on LaFeO 3 , CaTiO 3 , SrTiO 3 , and BaTiO 3 films.

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

Revealing the interplay between “intelligent behavior” and surface reconstruction of non-precious metal doped SrTiO 3 catalysts during methane combustion

The impact of surface reconstruction of a model perovskite, SrTiO 3 (STO), on CH 4 activation for combustion and oxidative coupling was previously revealed that the reaction rate was proportional to the creation of Srterminated step sites. Doped perovskites (SrTi 1-x M x O 3 , M=metal dopant) present yet another form of reconstruction throughout the surface and the bulk, where the metal dopant can migrate in and out of the perovskite lattice, also known as "intelligent behavior". In this work, understanding the interplay between perovskite surface reconstruction (surface termination) and the "intelligent behavior" is tackled for the first time, and the catalytic consequences are probed with CH 4 combustion as a model reaction. A set of experimental techniques, including XRD, Raman spectroscopy, X-ray adsorption spectroscopy, kinetic measurements, as well as DFT calculations were used to understand the catalytic behavior of the reconstructed surfaces of Ni and Cu-doped STO for methane combustion. Here, we found that during methane oxidation, the diffusion of Ni and Cu into the lattice due to the "intelligent behavior" is accompanied by Sr enrichment on the surface of the perovskite. This Srenrichment process is reversible when Cu or Ni species exsolute as clusters/nanoparticles upon H 2 treatment. Such a surface reconstruction is found to greatly impact the catalytic activity of doped perovskites towards methane combustion.

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

LaNi x Fe 1–x O 3 as flexible oxygen or carbon carriers for tunable syngas production and CO 2 utilization

The current study reports LaFe 1–x Ni x O 3–δ redox catalysts as flexible oxygen or carbon carriers for CO2 utilization and tunable production of syngas at relatively low temperatures (~700 °C), in the context of a hybrid redox process. Specifically, perovskite-structured LaFe 1–x Ni x O 3–δ with seven different compositions (x = 0.4–1) were prepared and investigated. Cyclic experiments under alternating methane and CO 2 flows indicated that all the samples exhibited favorable reactive performance: CH 4 and CO 2 conversions varied between 85% and 98% and 70–88%, respectively. While H 2 /CO ratio from Fe-rich redox catalysts was ~2.3:1 in the methane conversion step, Ni-rich catalysts produced a concentrated (~ 93.7 vol%) hydrogen stream via methane cracking. The flexibility of LaFe 1–x Ni x O 3–δ to produce syngas (or hydrogen) with tunable compositions was found to be governed by the iron/nickel (Fe/Ni) ratio. Redox catalysts with higher Fe contents act as a lattice oxygen carrier via chemical looping partial oxidation (CLPOx) of methane whereas those with higher Ni contents function as a carbon carrier via chemical looping methane cracking (CLMC) scheme. XRD analysis and temperature-programmed reactions revealed that both types of catalysts involve the formation of La 2 O 3 and Ni 0 /Ni-Fe phases under the methane environment. The ability to re-incorporate La 2 O 3 and Ni/Fe into a perovskite structure gives rise to oxygen-carrying capacity whereas stable Ni 0 or Ni/Fe phases would catalyze methane cracking without lattice oxygen exchange in the reaction cycles. Here, temperature programmed oxidation and Raman spectroscopy indicated the presence of graphitic and amorphous carbon species, which were effectively gasified by CO 2 to produce concentrated CO. Stability tests over LaFe 0.5 Ni 0.5 O 3 and LaNiO 3 revealed that the redox performance was stable over a span of 50 cycles.

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

A review of in situ/operando studies of heterogeneous catalytic hydrogenation of CO 2 to methanol

Repurposing CO 2 into chemicals, one of the Carbon Dioxide Removal (CDR) strategies, still faces significant challenges in conversion and energy efficiency due to the lack of effective catalysts and processes. Fundamental understanding through in situ/operando investigations of the reaction mechanisms and catalyst structures is pivotal for developing the efficient catalysts. This paper reviews the past and recent in situ/operando studies of methanol synthesis from heterogeneous CO 2 hydrogenation over a few typical catalysts including Cu-based, oxide-based, and noble-metal-based catalysts. With the development of high-pressure reactors, in situ/operando IR, X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), neutron diffraction and imaging have been used to reveal the surface intermediates and structures of working catalysts under CO 2 hydrogenation conditions. On the one hand, the combined operando techniques shed light on working mechanisms for some catalytic systems. On the other hand, due to the complexity of selective CO 2 hydrogenation reaction and limited sensitivity of current accessible operando techniques to the surface structure of catalysts, it is still murky about the exact nature of the active sites at the surface/interface and how different sites promote different reaction paths. Furthermore, it is concluded that new methodologies for differentiating signals from different sites, and the development of surface-sensitive techniques for high pressure reactions are needed for providing structural descriptors of highly active and selective CO 2 conversion catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Fate of arsenic during up to 4.5 years of aging of Fe III -As V coprecipitates at acidic pH: Effect of reaction media (Nitrate vs. Sulfate), Fe/As molar ratio, and pH

Iron-arsenate (Fe III -As V ) coprecipitate generated in acid mine drainage and hydrometallurgical practices is one of the potential sources of As contamination in the environment. However, the As behavior as well as the transformation process of the Fe III -As V coprecipitate is still not fully understood under acidic conditions. This work systematically studied the effect of reaction media (sulfate vs. nitrate), Fe/As molar ratios, and acidic pH values on the transformation rates, routes, and products of the Fe III -As V coprecipitates at different temperatures during up to 4.5 years of aging. X-ray diffraction (XRD), transmission electron spectroscopy (TEM), Raman spectroscopy, and extended X-ray absorption fine structure spectroscopy (EXAFS) results showed that the Fe III -As V coprecipitates with Fe/As = 2 transformed to scorodite at pH 4 in both sulfate and nitrate media with poorly crystalline ferric arsenate as precursor. In comparison, for the Fe/As = 4 samples, parascorodite and hematite were formed in sulfate and nitrate media, respectively. We note arsenic was released into the liquid phase during the aging process for the samples with Fe/As = 2 and 4. The aqueous As concentrations ([As] aq ) in sulfate media were larger than those in nitrate media for both the Fe/As = 2 and 4 samples. In addition, the transformation products were goethite and Na-jarosite at Fe/As = 8 and 16, pH 2.5 with the decrease of [As] aq . The results also indicated that 6-line ferrihydrite was a common intermediate for many Fe-As transformation processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Effect of operating parameters on H 2 /CO 2 conversion to methanol over Cu-Zn oxide supported on ZrO 2 polymorph catalysts: Characterization and kinetics

Kinetic aspects of the operating parameters for the catalytic conversion of H 2 /CO 2 to methanol over two novel catalysts were evaluated to understand the effect of the polymorphic ZrO 2 phase composed of Cu 0/+ -ZnO sites at the atomic level and its impact on the reaction mechanism. The catalysts were characterized by in situ and ex-situ XRD, N 2 adsorption/desorption isotherms, FRX, TPR, TPD-N 2 O, in situ XANES, TPD-CO 2 , and in situ DRIFTS techniques. The influence of different reaction variables such as the GHSV, temperature, pressure, and H 2 /CO 2 ratio were studied using a fixed bed continuous plug flow reactor. The Cu-ZnO catalyst supported on the tetragonal zirconia polymorph exhibited the highest methanol yield due to the lower activation energy when compared to the catalyst with a greater amount of the monoclinic phase. In addition, the catalysts were reused for 8 cycles of 6 hours to evaluate their stability, which can translate into lower costs for large-scale methanol production. As a result, the estimation of the kinetic parameters over Cu-Zn oxide supported on ZrO 2 polymorphs was significant for understanding the reaction mechanism, as well as to provide a pathway for scaling-up of the process.

36 MATERIALS SCIENCE↗