Carbon Black Oxidation Research Articles

Chemical Origin of in Situ Carbon Dioxide Outgassing from a Cation-Disordered Rock Salt Cathode.

In situ carbon dioxide (CO2) outgassing is a common phenomenon in lithium-ion batteries (LiBs), primarily due to parasitic side reactions at the cathode-electrolyte interface. However, little is known about the chemical origins of the in situ CO2 released from emerging Li-excess cation-disordered rock salt (DRX) cathodes. In this study, we selectively labeled various carbon sources with 13C in cathodes containing a representative DRX material, Li1.2Mn0.4Ti0.4O2 (LMTO), and performed differential electrochemical mass spectrometry (DEMS) during galvanostatic cycling in a carbonate-based electrolyte. When charging LMTO cathodes, electrolyte solvent (EC) decomposition is the dominant source of the CO2 outgassing. The amount of EC-originated CO2 is strongly correlated with the total surface area of carbon black in the electrode, revealing the critical role of electron-conducting carbon additives in the electrolyte degradation mechanisms. In addition, unusual bimodal CO2 evolution during the first cycle is found to originate from carbon black oxidation. Overall, the underlying chemical origin of in situ CO2 release during battery cycling is highly voltage- and cycle-dependent. This work further provides insights into improving the stability of DRX cathodes in LiBs and is envisioned to help guide future relevant material design to mitigate parasitic reactions in DRX-based batteries.

Sublimation and oxidation measurements of graphite and carbon black at high temperatures in a shock tube using absorption imaging and thermal emission

Surface mass loss rates due to sublimation and oxidation at temperatures of 3000–7000 K have been measured in a shock tube for graphite and carbon black (CB) particles. Diagnostics are presented for measuring surface mass loss rates by diffuse backlit illumination extinction imaging and thermal emission. The surface mass loss rate is found by regression fitting extinction and emission signals with an independent spherical primary particle assumption. Measured graphite sublimation and oxidation rates are reported to be an order of magnitude greater than CB sublimation and oxidation rates. It is speculated that the difference between CB and graphite surface mass loss rates is largely due to the primary particle assumption of the presented technique which misrepresents the effective surface area of an aggregate particle where primary particles overlap and shield inner particles. Measured sublimation rates are compared to sublimation models in the literature, and it is seen graphite shows fair agreement with the models while CB underestimates, likely a result of the particle shielding affect not being considered in the sublimation model.

Experimental study of CeO2 after hydrothermal aging on emission characteristics of carbon black oxidation process

The CeO2 catalyst is commonly utilized in diesel particulate filter (DPF) to promote soot regeneration. It is necessary to give a particular attention to the performance of hydrothermal aging and the effect on DPF regeneration characteristics. Based on the fixed-bed test bench, the gas and particle emission characteristics of carbon black (PU) oxidation following hydrothermal aging and sieving treatment of CeO2 are investigated under a 3% water concentration condition. CeO2 is subjected to characterization and analysis combined with X-ray Photoelectron Spectroscopy (XPS), Electron Spin Resonance Spectroscopy (ESR), X-ray Powder Diffraction (XRD), and Scanning Electron Microscopy (SEM). The results indicate that the addition of fresh CeO2 proves beneficial in improving the oxidation efficiency (η) of PU, reducing CO emission and the total average particle number (PN). Meanwhile, CO2 emission rapidly increases. After hydrothermal aging, the average catalyst size and agglomeration degree of CeO2 increase, resulting in an increase in lattice defects and bulk oxygen vacancies (VO-b). The reduction of surface oxygen vacancies (VO-s) plays a dominant role in the catalytic oxidation process of PU, leading to a decrease in η and CO2 emission, while CO increase; And the contact mode between CeO2 and PU, as well as alterations in the microstructure of CeO2, consequently contributing to hindering particle movement and reducing total PN. Furthermore, the sieving treatment of catalyst increases particle emission, but significantly promotes the η and reduces harmful gas CO. This research establishes a theoretical and experimental foundation for enhancing the hydrothermal stability of catalysts and controlling particle emission at the DPF outlet.

Experimental study on gas and particle emission characteristics of carbon black oxidation process in the presence of water and catalysts

The study of oxidation characteristics of carbon black particle is the basis to investigate the regeneration process and characteristics of diesel particulate filter (DPF). Based on the fixed-bed test bench, the gas and particle emission characteristics of carbon black oxidation process in the presence of water are investigated under different temperatures, Printex-U (PU) masses, and catalysts. The experimental results show that the rise of temperature and PU mass increases the emissions of CO, CO2 and the total average particle number (PN). The oxidation efficiency (η) increases with temperature, but decreases with PU mass. The addition of catalysts promotes PU oxidation, and reduces CO emission. Due to the influence of particle diffusion, CeO2 has slightly lower efficiency than Pt/Al2O3 in the same ratio (1:1), but it is beneficial to significantly reduce particle emission, especially as the ratio increases (1:5). Water decreases CO and the η in PU oxidation, and the negative impact is gradually reduced after 3 % water concentration; However, the PN significantly increases, and expands the particle size range, particularly at high temperature and adding Pt/Al2O3 (from about 10 nm to 6– 30 nm, and a large number of particles with 30– 100 nm are produced). Additionally, the CO2/CO ratio of carbon black oxidation gradually increases with water concentration. Controlling DPF regeneration needs to strike a balance between the benefits on increasing oxidation efficiency and the potential negatives on particulate and harmful gas emission.

O, N Coordination-Mediated Nickel Single-Atom Catalysts for High-Efficiency Generation of H2O2.

Electrochemical selective two-electron oxygen reduction shows great potential for on-site electrochemical production of hydrogen peroxide (H2O2). Herein, we demonstrated the synthesis of Ni single-atom sites coordinated by three oxygen atoms and one nitrogen atom (i.e., Ni-N1O3) supported by oxidized carbon black (OCB) by pyrolyzing nickel-(pyridine-2,5-dicarboxylate) coordination complexes. Aberration-corrected scanning transmission electron microscopy (AC-STEM) combined with X-ray absorption spectroscopy (XAS) proves the presence of atomically dispersed Ni atoms attached on OCB (labeled as Ni-SACs@OCB), in which Ni single atoms are stabilized by a N, O-mediated coordination configuration. This Ni-SACs@OCB catalyst shows high H2O2 selectivity (95%) in a range of 0.2-0.7 V undergoing a two-electron oxygen reduction process, with a kinetic current density of 2.8 mA cm-2 and a mass activity of 24 A gcat.-1 at 0.65 V (vs RHE). In practice, H-cells with Ni-SACs@OCB as catalysts displayed a high H2O2 production rate of 98.5 mmol gcat.-1 h-1 with negligible current loss during testing, suggesting the high H2O2 generation efficiency and robust stability. DFT theoretical calculations revealed that Ni single-atom sites coordinated by O, N coordination exhibit advantages in oxygen adsorption and increased reactivity toward the intermediate species, *OOH, which is beneficial to high selectivity for H2O2 production. This work provides a novel N, O-mediated four-coordinate nickel single-atom catalyst as a promising candidate for practical decentralized production of H2O2.

O2-Involved Electro-activation of Persulfate on Oxidized Carbon Black for Effective Sulfamethoxazole Degradation: Key Role of Side-Reactive Oxygen Reduction

The oxygen reduction reaction (ORR) was an unavoidable side reaction in the electro-activating persulfate (PS) process, especially on the ORR-active carbon materials, which has usually been ignored in previous reports. In this work, the O2/N2-involved electro-activation of the PS system was constructed to confirm the role of side-reactive ORR on oxidized carbon black (OCB) for sulfamethoxazole (SMX) degradation. With O2 involvement, 820.8 μM •OH was produced by PDS electro-activation, over 7 times more than 115.8 μM under N2 aeration, leading to a high SMX removal of 90.6% (only 67.8% under N2 aeration). Such a huge difference in •OH yield and SMX removal performance was mainly attributed to side-reactive 2e– ORR, in which as-generated H2O2 was electro-activated to produce abundant •OH and form an advanced homogeneous •OH/SO4•– oxidation system via mutual transformation with gradual acidification. Meanwhile, the introduction of oxygen functional groups and defects on the surface of carbon black calcined at 600 °C (CB600) also contributed to the improvement of SMX removal performance, attributing to their enhancing effects on SMX electro-adsorption, PDS electro-activation, and O2 electro-reduction. Thus, side-reactive oxygen reduction played the spontaneous and synergistic oxidation roles in the O2-involved electro-activating PS process, helping to design highly effective advanced oxidation systems in the future.

Preparation and application of modified carbon black nanofluid as a novel flooding system in ultralow permeability reservoirs

Conventional flooding systems have very low recovery rates in ultralow permeability reservoirs in virtue of the characteristics of high injection pressure, low permeability and small pores in such reservoirs. In this study, a novel surface-modified carbon black (MCB) nanofluid was prepared as a flooding system to resolve this problem. The preparation process of MCB nanoparticles was divided into three stages: (1) oxidation of carbon black (CB) nanoparticles, (2) acyl chlorination of oxidized carbon black (OCB) nanoparticles and (3) grafting of active groups onto the surface of acyl chloride carbon black (ACB) nanoparticles, and the main synthesis conditions, such as modifier concentration and grafting temperature, were optimized. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis indicated that the factional groups were successfully introduced onto the surface of CB nanoparticles, and the crystallinity of CB nanoparticles decreased gradually during the reaction process. Additionally, the dispersed stability, temperature resistance, salinity tolerance, wettability alteration and oil stripping ability were evaluated so as to obtain the performance of the MCB nanofluid. The results show that the average size of the MCB nanoparticles is approximately 72.3 nm, and the dispersed stability of the MCB nanofluid is much better than that of the CB nanofluid. Compared with the carbon black (CB) nanofluid, the MCB nanofluid shows stronger wettability alteration and oil stripping ability, and can also withstand the high temperature and high salt environment of oil reservoirs. 1 PV of MCB nanofluid can enhance oil recovery by 28.9%. Furthermore, the enhanced oil recovery (EOR) mechanisms for the MCB nanofluid are revealed through analysis of low oil–water IFT (IFT), wettability alteration and Wasan’s theory of structural disjoining pressure. This new type of environment-friendly flooding system injects vitality into the development of ultralow permeability reservoirs.

Photothermal process and its stimulate healing performance for catalyst-free OCB/epoxy vitrimer composite

Polymeric coatings, widely used in large-scaled outdoor applications including solar energy collection, metal protection and so on, are limited by short service life caused by degradation and structural damage due to constant exposure in air and external force. Here, oxidized carbon black (OCB)/epoxy vitrimer (EV) composite without catalysts, dispersants and pre-heating was prepared by facile solvent mixing method. The addition of OCB improved the stress relaxation rate of the composite and endowed high solar absorptance (α) at 94.57% and solar thermal efficiency (η) at 93.28%. The efficiency of remote and local photothermal-stimulated healing for micro scratches of the composite coating was as high as 95.08%. And the macroscopic damage repairing which was rarely reported can be about 100% by a novel photothermal patching method. Meanwhile, the composites also have behaviors of shape memory, reusability and ion transfer barrier performance. Overall, based on the advantages of facile preparation, cheap raw materials, high solar absorptance and solar thermal efficiency and excellent remote and local healing efficiency, the OCB/EV composite coatings have potential applications in solar energy harvesting and provides a new strategy for the local and contactless repair of polymeric coatings used in outdoor applications such as solar-energy collector, solar absorption systems and metal protection, especially for the repair of the macroscopic damage.

Photothermal healing performance of oxidized carbon black/epoxy vitrimer composite coating for metal protection

Epoxy vitrimers with thermal-healing ability are widely studied to prolong the service life of materials. But the conventional preparation and healing strategy, involving external catalysts, preheating, hot press or/and heating the entire coating, are not applicable for the large-scale applications. In this work, a room-temperature brushable oxidized carbon black (OCB)/epoxy vitrimer composite based on dynamic transesterification reaction with excellent protective performance and localized photothermal-healing was prepared by solvent method. No external catalysts, preheating and hot press was needed in the preparation process. The experimental results demonstrate that the composite coatings exhibited an excellent metal protective performance. The effective non-contact local photothermal-healing can be achieved in 20 Min., and the scratch width can apparently narrow over 95 % and the impedance moduli of the composite coatings can be recovered from 263 Ω·cm2 to above 108 Ω·cm2. The OCB/epoxy vitrimer composite coating, combining ideal metal protective performance with non-contact local photothermal-healing performance, has great promise for many practical applications in large-scale, such as metal protection and solar-energy collector.

Preparation of Pt catalysts supported on polyaniline modified carbon black and electrocatalytic methanol oxidation

The supports are of vital importance for supported catalysts. In this work, an excellent anode catalyst support for methanol oxidation reaction is prepared by using polyaniline (PANI) surface modified carbon black (CB), and Pt catalysts are supported on the surface of carbon black modified by polyaniline (Pt/PANI-CB). The characterizations of structure and morphology show that Pt nanoparticles with an average diameter of 2.89 nm are uniformly dispersed on the surface of carbon black modified by polyaniline. Compared with Pt supported on the surface of carbon black (Pt/CB) and commercial Pt/C catalysts, the optimal Pt/PANI-CB has higher electrocatalytic activity, and better stability for methanol oxidation reaction. In 0.5 M H2SO4 solution containing 0.5 M CH3OH, the area specific activity of Pt/PANI-CB is 1.81 mA cm−2Pt, and those of Pt/CB and Pt/C is 1.29 and 0.68 mA cm−2Pt. After 1000 cycles of cyclic voltammetry, the area specific activity retention of Pt/PANI-CB is 74.0%, while those of Pt/CB and Pt/C are 60.4% and 38.2%. Obviously, as a catalyst support, carbon black modified by polyaniline has broad application prospects.

Evaluating the Rheo-electric Performance of Aqueous Suspensions of Oxidized Carbon Black

HypothesisThe macroscopic properties of carbon black suspensions are primarily determined by the agglomerate microstructure built of primary aggregates. Conferring colloidal stability in aqueous carbon black suspensions should thus have a drastic impact on their viscosity and conductivity. ExperimentsCarbon black was treated with strong acids following a wet oxidation procedure. An analysis of the resulting particle surface chemistry and electrophoretic mobility was performed in evaluating colloidal stability. Changes in suspension microstructure due to oxidation were observed using small-angle X-ray scattering. Utilizing rheo-electric measurements, the evolution of the viscosity and conductivity of the carbon black suspensions as a function of shear rate and carbon content was thoroughly studied. FindingsThe carboxyl groups installed on the carbon black surface through oxidation increased the surface charge density and enhanced repulsive interactions. Electrostatic stability inhibited the formation of the large-scale agglomerates in favor of the stable primary aggregates in suspension. While shear thinning, suspension conductivities were found to be weakly dependent on the shear intensity regardless of the carbon content. Most importantly, aqueous carbon black suspensions formulated from electrostatically repulsive primary aggregates displayed a smaller rise in conductivity with carbon content compared to those formulated from attractive agglomerates.

Green Oxidation of Carbon Black by Dry Ball Milling

Green Oxidation of Carbon Black by Dry Ball Milling

NIR Photothermal-Responsive Shape Memory Polyurethane with Protein-Inspired Aggregated Chymotrypsin-Sensitive Degradable Domains.

Biodegradable shape memory polymers are promising biomaterials for stents used in minimally invasive surgical procedures such as intestinal stents. Herein, a series of biodegradable shape memory polyurethanes (SMPUs) containing a novel phenylalanine-derived chain extender (PHP) are synthesized. Inspired by the fact that the function of biomacromolecules such as proteins is rich and varied because of the multiple combinations of the amino acid in highly evolved biosystems, this study finds that the sequence distribution of PHP in SMPU will also have a great influence on the phase structure and degradation behavior, especially the difference of surface morphology caused by degradation. Considering that the transition temperature (Ttrans ) of SMPU obtained is higher than physiological temperature, oxidized carbon black (OCB) with the ability of photothermal conversion is introduced into SMPU, which can not only endow SMPU with near-infrared response shape recovery characteristics, but also enhance phase separation degree and mechanical properties of them. SMPU/OCB composites show excellent shape memory effect and rapid photothermal response, and they can be degraded by chymotrypsin with an adjustable degradation rate. These SMPU/OCB composites show broad potential for application as intestinal stents.

A sensitive and economical electrochemical platform for detection of food additive tert-butylhydroquinone based on porous Co3O4 nanorods embellished chemically oxidized carbon black

Artificial food preservatives are widely utilized across the globe to prolong shelf life of food. In this paper, a highly sensitive and cost-effective electrochemical sensor for the nanomolar detection of synthetic antioxidant tert-butyl hydroquinone (TBHQ) commonly used as a food preservative is reported. A hybrid nanocomposite was sonochemically prepared by embedding surface functionalized carbon black (FCB) on spinel Co3O4 nanorods. We used oxalic acid mediated co-precipitation approach in the synthesis of highly porous Co3O4 nanorods and CB was chemically oxidized using acid-treatment. Significant characterization techniques including XRD, SEM, mapping, Raman spectroscopy, FTIR, and EIS were utilized for analyzing morphological and structural properties of materials. The prepared hybrid nanocomposite modified electrode exhibited excellent electrochemical performance. A high sensitivity of 7.94 μA μM−1 cm−2, ultra-low detection limit of 1 nM, and quantification limit of 5 nM was achieved in TBHQ detection based on the modified electrode. Furthermore, the practicality of the developed electrochemical sensor in TBHQ detection is confirmed by conducting real sample analysis experiment in beef tallow, peanut oil, and lake water resulting in adequate recovery values.

Enhancing microbial electrocatalysis of metal-based bioanode by thermal oxidation of carbon black filler

Metal-based materials, like stainless steel (SS), have been proved to be a promising bioelectrodes and current collectors for microbial fuel cells (MFCs). The microbial electrocatalysis performance of these metal electrodes could be greatly enhanced by surface modification, e.g. reactive bonding nanocarbon. Herein, we report the enhancement of microbial electrocatalysis of metal-based bioanode by thermal oxidation of the nanocarbon conductive filler, carbon black (CB). Oxidation of CB by thermal treatment at 400 and 500 °C in air (denoted as CB-400, CB-500) only led to slightly increase of oxygen content, from 4.34% in pristine CB to 5.54% in CB-500, while by thermal treatment at 110 °C in nitric (denoted as CB-N) led to a great increase of oxygen content to 9.58%. Microbial electrocatalysis results revealed that though the CB-N had the highest oxygen content, the bioanode it modified did not bring improvement of microbial electrocatalytic performance; while the bioanode modified by CB-500 led to an approximately 20% current density increase comparing to that modified by pristine CB. The quinone oxygen-containing functional groups of the CB-500 filler resulted by thermal treatment were found to be crucial for the enhancement of microbial electrocatalysis of the bioanode, because they could act as mediators to enhance the mediated electron transfer. This study provided an effective strategy for enhancing the microbial electrocatalysis of CB/SS composite bioanode by the appropriate oxidation of CB.

Investigation on gas and particle emission characterization of carbon black oxidation process promoted by catalyst/ash

The study of the gas and particle emission characteristics during the oxidation of carbon black particles is the basis for exploring the particle emission characteristics during diesel particulate filter (DPF/CDPF) regeneration process. The gas and particle emission of Printex U (PU) particles oxidation under different oxidation temperatures and sample masses are investigated based on fixed bed and thermogravimetric analysis, and the oxidation processes are conducted under the cooperative effect of catalyst (CeO2)/ash (ZnO). The experimental results show that, with the increase of oxidation temperature, the CO/CO2 concentration, the extent of oxidation (η) and the total emitted solid particulate number (PN) increase, but the average particulate diameter (Da) range reduces from 60 to 100 nm to 20–40 nm. On the other hand, with the increase of PU mass, the CO/CO2 concentration and the total PN increase together, and the Da rises from about 30 nm to 40–160 nm, while the η decreases markedly. Both the CeO2 and ZnO nanoparticles can promote the PU oxidation process, and then reduce CO emissions, which lead to the rise the CO2 emissions. Beneficially, the η and the Da increase under the effect of CeO2 and ZnO, and the total PN decreases sharply. Adding catalyst (CeO2) and ash (ZnO) can effectively reduce the emission of small particle size (<23 nm) during oxidation process, which provides a research basis for controlling the emission of particles below 23 nm during DPF regeneration process.

Real-time observation and quantification of carbon black oxidation in an environmental transmission electron microscope: Impact of particle size and electron beam

Carbon black oxidation is a post-treatment method to control its properties for different applications, and its outcomes may depend on the particle size. Three different sizes of carbon blacks were oxidized in an environmental transmission electron microscope to study the size effect on their oxidation pathway and rate. The oxidation at the nanoscale has been quantified using the ASTM D3849-14a standard method for the carbon blacks and compared with the theory of solid particle burning, i.e., D2 law. This comparison confirms the validity of the diffusion-controlled burning model for all three samples oxidized at 800°C in the presence of oxygen molecules. Electron microscope images show surface burning is the governing mode under this condition. Oxidation under electron-beam irradiation shows that the oxidation rate reduces by ∼0%, 30%, and 80% for particles with 33, 112, and 356 nm in diameter, respectively. The results suggest that the electron beam is causing the atomic bonds to break and transform to the graphitic structure at relatively high temperatures (e.g., 800°C) that causes oxidation rate reduction in larger particles. Despite the reduction in oxidation rate as the initial size of carbon particles increases, observations show that surface burning is the dominant mode under electron-beam irradiation.

Real-Time Observation and Quantification of Carbon Black Oxidation in an Environmental Transmission Electron Microscope: Impact of Particle Size and Electron Beam

Real-Time Observation and Quantification of Carbon Black Oxidation in an Environmental Transmission Electron Microscope: Impact of Particle Size and Electron Beam

3D geometric modeling analysis of contact probability effect in carbon black oxidation over MnOx-CeO2 catalysts

MnOx-CeO2 composite catalysts have attracted interest from all over the world as promising catalysts for carbon black oxidation. The contact between carbon black and catalyst, and the surface physicochemical properties of the catalyst, are the main factors in carbon black oxidation, while the contact is a basic one affecting the ignition of the oxidation. In this work, MnOx-CeO2 catalysts with different geometric morphologies (nanorod and nanoparticle) are prepared to determine the effect of geometric morphology on the contact probability between catalysts and carbon black. Compared with the nanorod catalyst, nanoparticle catalyst is significantly advanced in catalytic activity (T10 = 314 °C, T50 = 346 °C, T90 = 383 °C) and relative contact probability (9.549, compared to the 7.639 of nanorod catalyst, according to the 3D geometric modeling). O2-TPD, H2-TPR, and In-situ UV Raman experiments reveal that the concentration of surface intrinsic oxygen vacancy of the two catalysts are approximative. The consumption of oxygen vacancy is based on the active sites provided, which is relative to the morphology. The better consumption results in better utilization of intrinsic active oxygen species in nanoparticle sample. This finding proves the correlation between contact probability and carbon black catalytic activity, and witnesses that the consumption efficiency of surface intrinsic oxygen vacancy is an initial factor in carbon black oxidation.

Oxygen reduction to hydrogen peroxide on oxidized nanocarbon: Identification and quantification of active sites

Two-electron electrochemical oxygen reduction reaction (ORR) on non-metallic nanocarbon catalysts yielding hydrogen peroxide (H2O2) has attracted considerable research attentions in the field of electrochemistry, catalysis and material science. Here, oxidized carbon black (OCB) with different amounts of surface oxygen functional groups were synthesized for ORR. OCB catalysts exhibited a significant activity improvement for the two-electron pathway comparing with non-oxidized ones. Identification and quantification of active sites for two-electron pathway of ORR process were further realized via linking the activity to structural compositions of OCB, and both carboxyl (–COOH) and carbonyl (-CO) groups were proved responsible for two-electron pathway ORR to produce H2O2. The intrinsic activity of –COOH (k-COOH = 1.34 × 10−7 mol−1) was found higher than that of -CO (k-CO = 0.25 × 10−7 mol−1). The present work provides new physical–chemical insights on the mechanism of oxygen reduction reactions on carbon-based catalysts, paving the way for the establishment of structure–function relations and further development of novel non-metallic catalytic systems.