Carbon Precursor Research Articles

Efficient capacitive deionization with hierarchical porous carbon flow electrodes

Flow-electrode capacitive deionization (FCDI) represents an innovative, chemically-free, and environmentally-friendly approach for desalination. However, the long-standing challenge of constrained electronic and ionic transport within its flow-electrode has impacted overall desalination performance. In this study, we explore novel concepts and advancements in capacitive deionization by utilizing hierarchical porous carbon (HPC) flow electrodes. By employing widely available sodium carboxymethyl cellulose as a carbon precursor and NaCl as an activator, we have successfully synthesized a carbon-based particle electrode featuring a hierarchical porous structure. The HPC electrode was further optimized through precise adjustments to its pore structure. The optimized electrode exhibited excellent dispersion, viscosity, and remarkable specific capacitance of 283.96 F g−1. Under optimal conditions of a 10% mass loading and an applied voltage of 1.2 V, the electrode demonstrated an average salt removal rate of 82.11 μg cm−2 min−1, a charge efficiency of 101.44%, and an energy consumption of 9.32 × 10−3 kWh mol−1. Furthermore, we investigated the optimal operating parameters for the FCDI device equipped with the HPC flow electrode. Impressively, the HPC flow electrode achieved a salt removal efficiency exceeding 80% over five cycles, maintaining an average salt removal rate of 54.00 μg cm−2 min−1 during 12 h of continuous operation. Detailed textural analysis and electrochemical characterizations revealed that the superior desalination performance is attributed to the hierarchical porous structure of the electrode. This unique structure significantly enhances both electronic and ionic transport within the FCDI system. Our study underscores the critical role of hierarchical porous carbon flow electrodes in capacitive deionization, paving the way for novel strategies to optimize ion and electron transport.

Enhancing the electrochemical performance of semicoke‐based hard carbon anode through oxidation‐crosslinking strategy for low‐cost sodium‐ion batteries

AbstractSemicoke, a coal pyrolysis product, is a cost‐effective and high‐yield precursor for hard carbon used as anode in sodium‐ion batteries (SIBs). However, as a thermoplastic precursor, semicoke inevitably graphitizes during high‐temperature carbonization, so it is not easy to form the hard carbon structure. Herein, we propose an oxidation‐crosslinking strategy to realize fusion‐to‐solid‐state pyrolysis of semicoke. The semicoke is first preoxidized using a modified alkali‐oxygen oxidation method to enrich its surface with carboxyl groups, which are localization points and the cross‐linking reactions occur with citric acid to build the semicoke precursor with homogeneous and abundant ‐C‐(O)–O‐ groups (up to 21 at% oxygen content). The ‐C‐(O)–O‐ groups effectively prevent the rearrangement of carbon microcrystals in semicoke during carbonization, resulting in the formation of an abundant pseudographite structure with larger carbon interlayer spacing and micropores. The optimized semicoke‐based hard carbon shows both a high initial Coulombic efficiency of 81% and a specific capacity of 307 mAh g−1, with low‐voltage plateau capacity increased to 2.5 times, compared to that of the unmodified semicoke carbon. By the combination of detailed discharge curves and in situ X‐ray diffraction analysis, the plateau capacity of semicoke‐based hard carbon is mainly derived from interlayer intercalation of Na+ ion. The proposed oxidation‐crosslinking strategy can contribute to the usage of low‐cost and high‐performance hard carbons in advanced SIBs.

Porous carbon derived from center part of the corn cob for high-performance symmetrical supercapacitors

The central part of agricultural waste biomass corn cob was used as carbon precursor and KHCO3 as activating agent, and porous carbon materials were prepared by one-step carbonization method. The effect of KHCO3 on the structure and properties of porous carbon was studied. The results show that KHCO3 has an etching effect on porous carbon, and the greater the amount of KHCO3, the stronger the etching effect. The obtained biomass porous carbon material has abundant pores, reasonable pore size distribution and high specific surface area, which is conducive to ion transfer and charge storage. In addition, the heteroatom self-doping of porous carbon can improve surface hydrophilicity and generate additional pseudocapacitance, thereby improving its electrochemical properties. Electrochemical characterization shows that the porous carbon has a specific capacitor of up to 323 F g−1. The assembled symmetric supercapacitor (SSC) has an energy density of 20 Wh kg−1 at a power density of 350 W kg−1. This low-cost, high-performance electrode material has potential applications in high-power supercapacitors.

Pre-oxidation modification of bituminous coal-based hard carbon for high-quality sodium ion storage

Bituminous coal, with its moderate anthracene content, high reactivity, and ease of modulation, stands out as a favorable choice as a precursor for hard carbon. However, due to the highly condensed aromatic rings in bituminous coal, it tends to form highly graphitized structures after high-temperature carbonization. Therefore, pretreatment of bituminous coal is necessary to suppress the graphitization process. Here, we combine pre-oxidation techniques with high-temperature carbonization to produce a cost-effective, high carbon yield, and superior performance coal-based hard carbon. When utilized as anode for sodium-ion batteries, the prepared coal-based hard carbon exhibits a high reversible capacity of 313.5 mAh g−1, along with excellent rate capability and long cycling stability.

Study on the performance of Co–Ni sulfide electrocatalysts supported by different fibroin-based carbon precursors

Research on sustainable energy sources is crucial for alleviating environmental issues and addressing energy security concerns. This study investigates the utilization of various silk precursors in the hydrogen evolution reaction. Waste silk fabric, regenerated silk fibroin film, porous silk fibroin, silk cocoon and degummed silk fibroin were used as precursors to prepare HER electrocatalysts. To investigate the influence of precursor form on catalytic perform9ance, a comparative analysis of the morphology, structure and composition of different materials was conducted. Among various catalysts, waste silk fabric based catalysts exhibit the most excellent catalytic activity, with an overpotential of 113 mV at 10 mA cm−2 and a Tafel slope of 30.9 mV/dec. Even After 1000 cycles of testing, it still maintains excellent catalytic activity. This study provides insights into the influence of precursor forms on the electrochemical performance of biomass carbon-based catalysts, aiming to inspire further research in this field.

Coal-based graphitized activated carbon for solar energy powered supercapacitor IoT applications

Solar cells show promise as energy conversion gadgets, but their extended use is limited by intermittent sunlight. Self-powered solar cell integration with an electrical energy storage system could be one solution to this problem. Therefore, we have developed a coin cell supercapacitor (SC) device based on coal-based graphitized carbon materials and integrated with solar cells to assess its efficiency for energy transformation and storage for practical validity. Supercapacitor carbon electrode was developed from a naturally abundant carbon precursor i.e. low-grade coal using molasses as binder, for the fabrication of high-quality SC devices. The fabricated supercapacitor exhibits a notable 127 F g−1 specific capacitance, maintaining 92 % of its initial value for up to 10,000 charge/discharge cycles at 5 A g−1, and a maximum energy density of 70.57 Wh kg−1 and power density of 2000.17 W kg−1. In order to create a self-sustaining power pack, the SCs (4 V) are integrated with a commercial solar cell (6 V, 750 mAh). Importantly, in the presenceof natural sunlight, the solar-powered as-fabricated supercapacitor bankcan significantly power a commercial IoT module (4–6 V, 600 mAh) demonstrating its potential for successful solar-to-electric energy transformation and storage. The findings demonstrate that solar-powered coal-based SC can be explored as an incredibly rapid future-proof energy storage technology that can help reduce energy demand in the foreseeable future.

Demystifying In Situ Pyrolysis Chemistry for High-Performance Polyanionic Cathodes in Sodium-Ion Batteries.

The carbon coating strategy has emerged as an indispensable approach to improve the conductivity of polyanionic cathodes. However, owing to the complex reaction process between precursors of carbon and cathode, establishing a unified screening principle for carbonaceous precursors remains a technical challenge. Herein, we reveal that carbonaceous precursor pyrolysis chemistry undeniably influences the formation process and performance of Na3V2(PO4)3 (NVP) cathodes from in situ insights. By investigating three types of carbonaceous precursors, it is found that O/H-containing functional groups can provide more bonding sites for cathode precursors and generate a reducing atmosphere by pyrolysis, which is beneficial to the formation of polyanionic materials and a uniform carbon coating layer. Conversely, excessive pyrolysis of functional groups leads to a significant amount of gas, which is detrimental to the compactness of the carbon layer. Furthermore, the substantial presence of residual heteroatoms diminishes graphitization. In this case, it is demonstrated that carbon dots (CDs) precursors with suitable functional groups can comprehensively enhance the Na+ migration rate, reversibility, and interface stability of the cathode material. As a result, the NVP/CDs cathode displays outstanding capacity retention, maintaining 92% after 10,000 cycles at a high rate of 50 C. Altogether, these findings provide a valuable benchmark for carbon source selection for polyanionic cathodes.

Rapid microwave fabrication of highly luminescent nitrogen and phosphorous co-doped carbon quantum dots for the determination of glutathione in pharmaceutical supplements

A facile and sensitive nano-probe for spectrofluorometric glutathione (GSH) determination has been developed based on dual-doped nitrogen and phosphorus carbon quantum dots (NP@CQDs). The NP@CQDs were prepared, through a rapid, one-step microwave heating method in only 180 s with a high quantum yield (0.63) using ethylenediaminetetraacetic acid as carbon and nitrogen precursor and diammonium hydrogen phosphate as nitrogen and phosphorus dopant. The synthesised NP@CQDs had a maximum bluish fluorescence emission at 420 nm, after excitation at 360 nm. The luminescence of the prepared NP@CQDs was quenched via a static quenching mechanism by ferrous ions, while ferric ions did not affect the emission of NP@CQDs. GSH was mixed with ferric ions before adding NP@CQDs to exploit this observation. The attenuation in emission observed after adding NP@CQDs to GSH/ferric ions was directly related to the GSH concentration, as GSH worked to reduce the ferric ions present and produce ferrous ions. The proposed fluorometric method was validated in compliance with the International Council on Harmonization (ICH) guidelines. The proposed fluorescent nano-probe showed good linearity for GSH determination over a range of 0.5–10 µg/mL with % recoveries ranging between 99.50 and 101.86 %, and RSD less than 2 %. NP@CQDs were implemented for GSH determination in pharmaceutical supplementary capsules with respectable accuracy and precision. This approach is simple, reliable, accurate, specific, and it also does not require expensive chemicals or sophisticated equipment. This work opens up other uses of NP@CQDs in pharmaceutical and environmental analysis.

Impact of H2 Reduction on the Performance and Stability of Phenol Catalytic Wet Air Oxidation (CWAO) Over Cu−Ce/AC Catalysts

AbstractIn this study, we utilized the carbon precursor derived from walnut shells to synthesize a series of Ce‐modified Cu‐based carbon catalysts (Cu−Ce/AC) via the impregnation method. We investigated the performance and stability of Cu−Ce/AC catalysts for CWAO phenol after H2 reduction at various temperatures. The Cu−Ce/AC‐250 catalyst exhibited its highest performance at 250 °C, achieving complete phenol conversion. Characterization results from techniques including XRD, BET, FTIR, ICP‐OES, SEM‐EDS, XPS, and H2‐TPR indicated that the active components of the H2‐reduced catalysts were more evenly distributed across the catalyst surface, thereby enhancing the availability of reactive sites for phenol oxidation. Simultaneously, under the appropriate temperature, the H2 atmosphere can reduce a portion of the Cu2+ on the catalyst surface to Cu+, thereby mitigating the loss of Cu components.

Synthesis of Highly Porous Lignin-Sulfonate Sulfur-Doped Carbon for Efficient Adsorption of Sodium Diclofenac and Synthetic Effluents.

Herein, a novel sulfur-doped carbon material has been synthesized via a facile and sustainable single-step pyrolysis method using lignin-sulfonate (LS), a by-product of the sulfite pulping process, as a novel carbon precursor and zinc chloride as a chemical activator. The sulfur doping process had a remarkable impact on the LS-sulfur carbon structure. Moreover, it was found that sulfur doping also had an important impact on sodium diclofenac removal from aqueous solutions due to the introduction of S-functionalities on the carbon material's surface. The doping process effectively increased the carbon specific surface area (SSA), i.e., 1758 m2 g-1 for the sulfur-doped and 753 m2 g-1 for the non-doped carbon. The sulfur-doped carbon exhibited more sulfur states/functionalities than the non-doped, highlighting the successful chemical modification of the material. As a result, the adsorptive performance of the sulfur-doped carbon was remarkably improved. Diclofenac adsorption experiments indicated that the kinetics was better described by the Avrami fractional order model, while the equilibrium studies indicated that the Liu model gave the best fit. The kinetics was much faster for the sulfur-doped carbon, and the maximum adsorption capacity was 301.6 mg g-1 for non-doped and 473.8 mg g-1 for the sulfur-doped carbon. The overall adsorption seems to be a contribution of multiple mechanisms, such as pore filling and electrostatic interaction. When tested to treat lab-made effluents, the samples presented excellent performance.

Chitosan-derived activated carbon/chitosan composite beads for adsorptive removal of methylene blue and acid orange 7 dyes

In this study, a chitosan/activated carbon composite was developed for the sustainable removal of dye pollutants from activated carbon derived from chitosan. First, chitosan was converted into chitosan-derived activated carbon (C-AC) with a large Brunauer-Emmett-Teller (BET) surface area of 2428 m2/g through carbonization using a potassium hydroxide (KOH) chemical activator. To enable simple separation from contaminated water and sustainable use in the adsorption process, the generated C-AC was incorporated into a bead-type, stable three-dimensional chitosan polymer network structure. The prepared C-AC-incorporated chitosan beads showed excellent adsorption capacity for the anionic acid orange 7 (AO) (511.38 mg/g) and the cationic methylene blue (MB) (413.08 mg/g). In addition, it maintained structural stability even in various pH environments and could be easily separated from contaminated water. The C-AC-incorporated chitosan beads showed excellent reusability and durability, maintaining at least 82% and 86% removal efficiencies for AO and MB dyes even after five reuses. This study suggests the potential use of chitosan as an eco-friendly adsorbent that can be utilized simultaneously as an activated carbon precursor and as a matrix for robust bead-like polymer composites.

Activated Carbon for CO2 Adsorption from Avocado Seeds Activated with NaOH: The Significance of the Production Method.

The rise in atmospheric greenhouse gases like CO2 is a primary driver of global warming. Human actions are the primary factor behind the surge in CO2 levels, contributing to two-thirds of the greenhouse effect over the past decade. This study focuses on the chemical activation of avocado seeds with sodium hydroxide (NaOH). The influence of various preparation methods was studied under the same parameters: carbon precursor to NaOH mass ratio, carbonization temperature, and nitrogen flow. For two samples, preliminary thermal treatment was applied (500 °C). NaOH was used in the form of a saturated solution as well as dry NaOH. The same temperature of 850 °C of carbonization combined with chemical activation was applied for all samples. The applied modifications resulted in the following textural parameters: specific surface area from 696 to 1217 m2/g, total pore volume from 0.440 to 0.761 cm3/g, micropore volume from 0.159 to 0.418 cm3/g. The textural parameters were estimated based on nitrogen sorption at -196 °C. The XRD measurements and SEM pictures were also performed. CO2 adsorption was performed at temperatures of 0, 10, 20, and 30 °C and pressure up to 1 bar. In order to calculate the CO2 selectivity over N2 nitrogen adsorption at 20 °C was investigated. The highest CO2 adsorption (4.90 mmol/g) at 1 bar and 0 °C was achieved.

Waxberry-like Mo2C@N doped carbon hierarchical structures for broadband electromagnetic absorptions

Broadband electromagnetic absorption materials showcase advantages for coping the increasingly complicated electromagnetic pollution and interferences. Among them, carbon-based materials, with light weight and high stability, are potential ideal electromagnetic absorption materials. The broadband design strategy for carbon-based electromagnetic absorption materials usually involves with hierarchical structure and interface engineering, which is often costly or complex. In this paper, the phosphomolybdic acid is designed to simultaneously serve as the doping protonic acid, as well as the doping Mo source. Waxberry-like Mo2C@N doped carbon hierarchical structures are synthesized through the carbonization of low-cost polyaniline precursors. The hierarchical structures exhibit significantly enhanced electromagnetic absorptions. The optimal RL reaches −50.4 dB, and the effective bandwidth can reach 5.1 GHz at a thickness of 2.0 mm. The enhanced electromagnetic absorptions are mainly attributed to the microscale waxberry-like hierarchical structure, the Mo2C and N doped carbon polarization structures, as well as the asymmetric Mo–N interfacial hybridizations. This work provides a reference path for the design of broadband carbon-based electromagnetic absorption materials.

Plasma-enabled growth of vertically oriented carbon nanostructures for AC line filtering capacitors

Self-standing vertically oriented carbon nanostructures (VCNs) were synthesized using a large-scale microwave plasma under low-pressure conditions, employing methane as a carbon precursor. The influence of plasma operational and substrate conditions on nanostructure growth and morphology were systematically studied. Furthermore, post-synthesis N-doping of VCNs with nitrogen content of 2.4 at% N was achieved using an Ar-N2 microwave plasma. Plasma-enabled direct deposition of VCNs, both doped and un-doped, onto nickel foils has been accomplished. The assessment of the developed nanostructures as electrodes in high-frequency AC filtering capacitors, has demonstrated an overall capacitance of approximately 480 µF at 100 Hz, with a cut-off frequency of 4 kHz for a phase angle of −45°. The excellent electrochemical performance can be attributed to the appropriate structural and morphological properties peculiar for the directly deposited on nickel foil VCNs providing binder-free electrode fabrication, thus enhancing the electrode’s conductivity and charge transfer kinetics. This plasma-enabled approach for electrode design on a large scale, coupled with excellent filtering performance, paves the way for many applications in high-frequency scenarios, offering an environmentally friendly alternative to conventional electrolytic capacitors.

Promoting surface lattice oxygen and oxygen vacancy of CeO2 for photothermal methane dry reforming over Ni/CeO2 catalysts

The ever-increasing concentrations of CH4 and CO2 result in the greenhouse effect around the world. It’s meaningful to transform the gases for environment protection. In this work, we studied photothermal methane dry reforming over Ni/CeO2 catalysts by shaping CeO2 to nanorods and nanosheets, converting the greenhouse gases to syngas and trying to resolve challenges of Ni sintering and carbon deposition in the reaction. Through characterizations of physicochemical and optical properties, the surface lattice oxygen and oxygen vacancy were verified being more promoted on the nanorods catalysts than on the nanosheets catalysts, giving the greater reforming performance. The irradiation of visible-light accelerated CH4/CO2 rates, which was originated from that the photoelectrons reduced CO2 and the holes oxidized CHx. The oxygen vacancy strengthened metal-support interaction limiting Ni sintering, and the surface lattice oxygen gasified carbon precursors decreasing carbon deposition. The synergism between thermocatalysis and photocatalysis on the optimized 5Ni/CeO2 nanorod catalyst contributed to CH4 and CO2 rates up to 204 μmol/(gcats) and 245 μmol/(gcats), respectively, at 973 K, and carbon deposition less than 0.5 wt%. These were much superior to most reported performance. The work provided a novel photothermal approach for significantly decreasing carbon deposition in methane dry reforming.

Can Two-Dimensional Correlation Spectroscopy (2D-COS) Indicate Biocompatible Material?

Carbon nanofibers are a new type of carbon materials. One of the methods of obtaining them is the carbonization of a polymer precursor. They are attractive in many areas, including medicine, due to the possibility of modifying their properties in a wide range. For example, the conditions of the carbonization process result in the creation of materials with designed structures and surface parameters. In the current work, the nanoprecursor was polyacrylonitrile (PAN) fibers. Two types of carbon fibers obtained by carbonization of the PAN precursor at 1000 °C were tested. The first electrospun carbon nanofibers (ESCNFs) were cytotoxic, while the second ESCNF-f were biocompatible after functionalization. The parameters obtained from Raman tests did not clearly discriminate between the tested materials. Multiwavelength Raman studies, analyzed using the two-dimensional correlation spectroscopy (2D-COS), treating the laser energy as an external disturbance, showed a difference between both fibrous structures. 2D-COS indicates that structures resembling graphite systems, devoid of disordered carbon forms, are nontoxic.

Metal Acetylene Dicarboxylates as Catalyst for Printable Low Temperature Carbon Precursors

The synthesis of various metal acetylene dicarboxylates (MxADC, M = Cu, Ag, Fe, Co, Ni) via new methods are reported. The previously unknown crystal structures for Ag2ADC and FeADC are presented. The behaviour of the different metal dicarboxylates and their role as graphitization catalysts in a printable highly energetic carbon precursor is investigated in detail. Despite the copper compound has the lowest decomposition temperature of all studied acetylene dicarboxylates and is significantly enhancing the conductivity of carbon thin films obtained at low pyrolysis temperatures, the catalytic effect of cobalt and iron on graphitizing carbon results in a superior conductivity in carbon thin films pyrolyzed at lower temperatures down to 600°C. The newly designed precursors are demonstrated to produce micro‐supercapacitors with a 3D‐piezoelectric inkjet technique at low pyrolysis temperature.

Molten salt-mediated hierarchical porous carbon derived from biomass waste for high-performance capacitive storage

Biomass-derived carbon (BDC) materials are the suitable precursors for the fabrication of carbon electrodes of supercapacitors because of the sustainability, environmental friendliness, power capability, and structural diversity. The fabrication of BDC with low cost and excellent electrochemical properties is important for the practical applications of BDC in energy storage fields. Herein, ambrosia melon peels are used as carbon precursors for the fabrication of sustainable BDC electrodes through the molten salt-mediated pyrolysis procedure. The ambrosia melon peels-derived porous carbon (AMPPC) possesses high specific surface area of 529.9 m2 g−1. The AMPPC electrode shows the charge storage behavior of electrical double-layer capacitance with high ionic conductivity, high specific capacitance (218.3 F g−1 at 0.5 A g−1) and outstanding rate performance. In addition, the symmetric supercapacitor based on the AMPPC electrodes presents high specific energy density and specific power density (8 kW kg−1). It can be used as energy source to power helicopter model, clock, and calculator. Thus, the work gives an inspiration of design of BDC from the low-cost biomass waste and provides a simple way for the fabrication of BDC for the carbon electrodes of supercapacitors, lithium-ion batteries and so on.

Alleviated volume changes of germanium anode via facile chemical confinement strategy

Germanium (Ge) anode shows great promise in overcoming unsatisfied capacity and dendrite formation concerns facing conventional graphite anodes in next generation lithium ion batteries. However, volume changes during repeated alloying and de-alloying cycles seriously impair structural stability and cycle lifespan. In this work, a facile chemical confinement strategy has been firstly proposed to alleviate volume changes of Ge anode. Benefited from strong binding interaction between Ge and ZnS, discrete Ge nanoparticle can be successfully encapsulated within thin protective ZnS shell and N-doped carbon layer (Ge-ZnS@N-C) after two-step carbonization and sulfurization of polydopamine-coating Zn2GeO4 nanorod precursors. In contrast, bulk Ge aggregates and hollow N-doped carbon nanotubes can be formed without chemical confinement of ZnS. The as-prepared Ge-ZnS@N-C sample displays multifold structural merits, including nanosized Ge particles with highly electrochemical activity, sufficient pores and functional groups that facilitate ion diffusion. Besides, protective ZnS shell and N-doped carbon layer can suppress volume changes of Ge nanoparticles and guarantee high electrode reversibility, demonstrated by a series of in-situ and ex-situ experiments. The as-synthesized Ge-ZnS@N-C anodes exhibit stable long-cycle performance (1389.7 mAh/g after 450 cycles at a current density of 0.5 A/g) and excellent rate performance (548.5 and 397.8 mAh/g at 5.0 and 8.0 A/g, respectively).

Synthesis of Wafer-Scale SWCNT Forests with Remarkably Invariant Structural Properties in a Bulk-Diffusion-Controlled Kinetic Regime

Robust synthesis of vertically aligned carbon nanotubes (VACNT) at large scale is required to accelerate deployment of numerous cutting-edge devices to emerging commercial applications.1 Large-area single-walled (SW) CNT forests with high densities and small diameters are especially important for many applications, yet they are conspicuously absent from the literature due to reproducibility and synthesis challenges, which are further exacerbated when flexible metal foils are used as support instead of traditional Si or quartz wafers. To address this need, we demonstrate that the structural characteristics of SWCNTs produced in a growth regime dominated by bulk diffusion of the gaseous carbon precursor are remarkably invariant over a broad range of process conditions (precursor concentration increased up to 30-fold, catalyst substrate area from 1 cm2 to 180 cm2, growth pressure from 20 to 790 mbar, and gas flowrates up to 8-fold).2 Forests structural properties are also preserved when growth is transitioned from Si wafers to Inconel metal foils.3 We show that a simple growth kinetics model that accounts for both reactant bulk diffusion and competing byproduct formation in the presence of excess hydrogen quantitatively reproduces the experimental data in the entire isothermal parameter space. The model enables critical predictions for process scale-up optimization including a potential 6-fold increase in CNT production rate, a ~ 90% carbon conversion efficiency in select conditions, and elimination of reaction rate decay observed at high pressures by using a hydrogen-free growth environment. This model-guided opportunity to substantially improve synthesis throughput and efficiency, in conjunction with the remarkably invariant CNT properties on both metal and insulating substrates, is appealing for reliable VACNT device fabrication at both small and industrial scales.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. References Rao, R.; Pint, C. L.; Islam, A. E.; Weatherup, R. S.; Hofmann, S.; Meshot, E. R.; Wu, F.; Zhou, C.; Dee, N.; Amama, P. B.; Carpena-Nuñez, J.; Shi, W.; Plata, D. L.; Penev, E. S.; Yakobson, B. I.; Balbuena, P. B.; Bichara, C.; Futaba, D. N.; Noda, S.; Shin, H.; Kim, K. S.; Simard, B.; Mirri, F.; Pasquali, M.; Fornasiero, F.; Kauppinen, E. I.; Arnold, M.; Cola, B. A.; Nikolaev, P.; Arepalli, S.; Cheng, H.-M.; Zakharov, D. N.; Stach, E. A.; Zhang, J.; Wei, F.; Terrones, M.; Geohegan, D. B.; Maruyama, B.; Maruyama, S.; Li, Y.; Adams, W. W.; Hart, A. J. Carbon Nanotubes and Related Nanomaterials: Critical Advances and Challenges for Synthesis toward Mainstream Commercial Applications. ACS Nano 2018, 12, 11756-11784.Park, S. J.; Moyer-Vanderburgh, K.; Buchsbaum, S. F.; Meshot, E. R.; Jue, M. L.; Wu, K. J.; Fornasiero, F. Synthesis of wafer-scale SWCNT forests with remarkably invariant structural properties in a bulk-diffusion-controlled kinetic regime. Carbon 2023, 201, 745-755.Moyer-Vanderburgh, K.; Ma, M. C.; Park, S. J.; Jue, M. L.; Buchsbaum, S. F.; Wu, K. J.; Wood, M.; Ye, J.; Fornasiero, F. Growth and Performance of High-Quality SWCNT Forests on Inconel Foils as Lithium-Ion Battery Anodes. ACS Appl Mater Interfaces 2022, 14, 54981-54991.