Internal Carbon Research Articles

SEI-Coated Carbon Particles: Electrochemomechanical Fracture Mechanisms

By starting from fundamental physical principles, a generalized theoretical framework was developed to engineer the intercalation-induced mechanical degradation in SEI-coated carbon particles from the surrounding electrolyte in rechargeable lithium-ion batteries (LIBs). Six elemental regimes of fracture formation in spherical electrochemically active carbon particles of radius, r p , coated with an SEI layer of thickness, δ ≪ r p , have been identified: The pristine regime, the SEI debonding regime, the SEI surface flaw regime, the surface carbon flaw regime (delithiation), the internal circular carbon flaw regime (lithiation), and the carbon exfoliation regime (lithiation); as well as four combined regimes during delithiation and four combined regimes during lithiation. Results are summarized in terms of C-Rate versus particle size, degradation maps, to identify LIB operation conditions where the performance can be optimized, while suppressing the decrepitation of the SEI-coated carbon particle system. Improved porous electrode layers that deliver longer battery life are possible by selecting electrolytes that considering the design of SEI-coated carbon particles of tailored elastic stiffness and critical stress intensity factor, so that they are safe from developing a chemomechanically induced flaw, exfoliation, or carbon re-forming, during both lithiation or delithiation in the 1 to 10 μm size particle, and C-Rates < 1 C.

Dominance of net autotrophy in arid landscape low relief polar lakes, Nunavut, Canada.

The Arctic is the fastest warming biome on the planet, and environmental changes are having striking effects on freshwater ecosystems that may impact the regional carbon cycle. The metabolic state of Arctic lakes is often considered net heterotrophic, due to an assumed supply of allochthonous organic matter that supports ecosystem respiration and carbon mineralization in excess of rates of primary production. However, lake metabolic patterns vary according to regional climatic characteristics, hydrological connectivity, organic matter sources and intrinsic lake properties, and the metabolism of most Arctic lakes is unknown. We sampled 35 waterbodies along a connectivity gradient from headwater to downstream lakes, on southern Victoria Island, Nunavut, in an area characterized by low precipitation, organic-poor soils, and high evaporation rates. We evaluated whether lakes were net autotrophic or heterotrophic during the open water period using an oxygen isotopic mass balance approach. Most of the waterbodies were autotrophic and sites of net organic matter production or close to metabolic equilibrium. Autotrophy was associated with higher benthic primary production, as compared to its pelagic counterpart, due to the high irradiance reaching the bottom and efficient internal carbon and nutrient cycling. Highly connected midstream and downstream lakes showed efficient organic matter cycling, as evidenced by the strong coupling between gross primary production (GPP) and ecosystem respiration, while decoupling was observed in some headwater lakes with significantly higher GPP. The shallow nature of lakes in the flat, arid region of southern Victoria Island supports net autotrophy in most lakes during the open water season. Ongoing climate changes that lengthen the ice-free irradiance period and increase rates of nutrient evapoconcentration may further promote net autotrophy, with uncertain long-term effects for lake functioning.

First application of the novel anaerobic/aerobic/anoxic (AOA) process for advanced nutrient removal in a wastewater treatment plant

The stringent effluent quality standards in wastewater treatment plants (WWTPs) can effectively mitigate environmental issues such as eutrophication by reducing the discharge of nutrients into water environments. However, the current wastewater treatment process often struggles to achieve advanced nutrient removal while also saving energy and reducing carbon consumption. The first full-scale anaerobic/aerobic/anoxic (AOA) system was established with a wastewater treatment scale of 40,000 m3/d. Over one year of operation, the average TN and TP concentration in the effluent of 7.53 ± 0.81 and 0.37 ± 0.05 mg/L was achieved in low TN/COD (C/N) ratio (average 5) wastewater treatment. The post-anoxic zones fully utilized the internal carbon source stored in pre-anaerobic zones, removing 41.29 % of TN and 36.25 % of TP. Intracellular glycogen (Gly) and proteins in extracellular polymeric substances (EPS) served as potential drivers for post-anoxic denitrification and phosphorus uptake. The sludge fermentation process was enhanced by the long anoxic hydraulic retention time (HRT) of the AOA system. The relative abundance of fermentative bacteria was 31.66 - 55.83 %, and their fermentation metabolites can provide additional substrates and energy for nutrient removal. The development and utilization of internal carbon sources in the AOA system benefited from reducing excess sludge production, energy conservation, and advanced nutrient removal under carbon-limited. The successful full-scale validation of the AOA process provided a potentially transformative technology with wide applicability to WWTPs.

Unravelling the Path to Green Banking: A Case Study of Karnataka Bank

Purpose: Banks are adopting the concept of green banking to minimize both external and internal carbon emissions, which is an emerging trend. This paper aims to study the emerging trends of Green banking in India. The major purpose of the research article is to investigate the concept of green banking initiatives by Karnataka Bank and to examine the problems faced by Karnataka Bank to reach its green banking goals. Karnataka Bank Ltd.’ is the leading top ‘A’ c1ass schedu1ed Indian Commercial Bank. As a premier bank, a diverse array of products and services has been created and tailored to fulfill the varying business or personal requirements of customers. It is one of the leading emerging financial service institutions in India which has several branches all over India Methodology: In pursuit of the paper’s goals, secondary data sources such as books, journals, articles, newspapers, and websites have been employed. Findings: Private and public sector banks have taken necessary steps to reduce carbon emissions. All customers of the bank are offered green products and services and also more concern is shown towards environmental issues. The initiatives taken by most Indian Banks and the offering of green products and services by banks have proved to help preserve environmental balance and achieve sustainable development. Originality/Value: Based on the data available from secondary sources, the paper attempts to examine green banking practices in India and the initiatives of Karnataka Bank. Paper Type: Case Study

Insights into the Mechanism of O(3P)-Mediated Oxidation of Alkenes through Kinetic Isotope Effects and Computational Modeling.

Photodeoxygenation of aryl sulfoxides, such as dibenzothiophene S-oxide (DBTO), produces atomic oxygen [O(3P)] in solution. The mechanism of alkene oxidation with O(3P) remains uncertain. To address this, the current study utilized kinetic isotope effects (KIEs) and computational approaches to study the reaction of O(3P) with styrene and its isotopologues. Notably, the 2° CH/D KIE at the internal and terminal carbons of the reactive π-bond was ∼1.00 and ∼0.87, respectively. These findings indicate a terminal addition of O(3P) to the π-bond, supporting a stepwise oxidation pathway. Both epoxide and aldehyde products go through the same rate-determining transition state and then diverge based on the intermediate conformation. The O-C-C-C dihedral angle (φ) on the triplet surface dictates the product distribution, where φ = 50° or 310° leads to epoxide formation and φ = 180° leads to aldehyde formation. Computational modeling suggests that the epoxide is formed through rapid ring closure upon intersystem crossing from the triplet to the singlet ground state. Similarly, the aldehyde is generated via a 1,2-H shift immediately following intersystem crossing. This study integrates experimental and computational methods to understand the O(3P)-mediated oxidation of alkenes, providing supporting evidence for a stepwise addition mechanism.

Internal carbon recycling by heterotrophic prokaryotes compensates for mismatches between phytoplankton production and heterotrophic consumption.

Molecular observational tools are useful for characterizing the composition and genetic endowment of microbial communities but cannot measure fluxes, which are critical for the understanding of ecosystems. To overcome these limitations, we used a mechanistic inference approach to estimate dissolved organic carbon (DOC) production and consumption by phytoplankton operational taxonomic units and heterotrophic prokaryotic amplicon sequence variants and inferred carbon fluxes between members of this microbial community from Western English Channel time-series data. Our analyses focused on phytoplankton spring and summer blooms, as well as bacteria summer blooms. In spring blooms, phytoplankton DOC production exceeds heterotrophic prokaryotic consumption, but in bacterial summer blooms heterotrophic prokaryotes consume three times more DOC than produced by the phytoplankton. This mismatch is compensated by heterotrophic prokaryotic DOC release by death, presumably from viral lysis. In both types of summer blooms, large amounts of the DOC liberated by heterotrophic prokaryotes are reused through internal recycling, with fluxes between different heterotrophic prokaryotes being at the same level as those between phytoplankton and heterotrophic prokaryotes. In context, internal recycling accounts for approximately 75% and 30% of the estimated net primary production (0.16 vs 0.22 and 0.08 vs 0.29μmoll-1 d-1) in bacteria and phytoplankton summer blooms, respectively, and thus represents a major component of the Western English Channel carbon cycle. We have concluded that internal recycling compensates for mismatches between phytoplankton DOC production and heterotrophic prokaryotic consumption, and we encourage future analyses on aquatic carbon cycles to investigate fluxes between heterotrophic prokaryotes, specifically internal recycling.

Tunable internal structure carbon sphere synthesis driven by water-solubility and its application in gas separation.

A method for synthesizing carbon spheres with a tunable particle size and internal structure from polyfurfuryl alcohol (PFA) was developed. By tuning the concentration of a structure directing agent (polypropylene glycol, PPG), we found a mechanism to tune the inner architecture of carbon spheres driven by water-solubility. A mixture of PFA and PPG transferred from the "water-in-oil" phase to an "oil-in-water" phase with an increasing content of PPG because of a difference in water-solubility between furfuryl alcohol (FA), PFA, and PPG. As a result, the internal morphology of the carbon sphere evolved from a "cheese-like" to a "pomegranate-like" structure, which was accompanied by an increasing specific surface area and pore volume. Furthermore, the separation of C2H2 and C2H3Cl was tested on the 25%-FACS (furfuryl alcohol-based carbon sphere) sample under different activation treatments with CO2 or CO2-NH3, with the coexisting "cheese-like" and "pomegranate-like" inner structures, owing to its moderate pore volume and mechanical strength. The maximum adsorption capacity of C2H3Cl reached 0.77 mmol g-1, while C2H2 was adsorbed in significantly lower quantities. It is believed that the high polarizability and high dipole moment of the C2H3Cl molecule primarily contribute to the excellent performance of C2H2 and C2H3Cl separation, and the introduction of polar N-containing groups on the carbon skeleton further promotes C2H3Cl adsorption.

Anatomia e fisiologia foliar de cultivares de alho relacionadas à tolerância a fatores ambientais

Abstract The objective of this work was to evaluate the physiological and anatomical characteristics of garlic cultivar leaves that indicate tolerance or susceptibility to environmental factors. The experiment was conducted in a greenhouse in a completely randomized design, with eight treatments (cultivars). The evaluated cultivars were Amarantes, BRS Hozan, Caçador, Crespo, Chinês Folha Fina, Chonan, Gigante Roxo Escuro, and Ito. The following physiological variables were evaluated: net photosynthetic rate, stomatal conductance to water vapor, transpiration, internal and external carbon, and water use efficiency. The anatomical characteristics were analyzed with a microscope coupled to a camera. The Chinês Folha Fina, Chonan, Gigante Roxo Escuro, and Crespo cultivars showed higher mean photosynthetic rates and thicker photosynthetic tissues than the others. The Chonan and Crespo cultivars stood out for their higher photosynthetic rates, higher stomatal indices, thicker cuticle and epidermis, and larger mesophyll intercellular spaces, which are characteristics common to plants tolerant to water deficit. The characteristics of the Chonan and Crespo garlic cultivars are related to drought tolerance, and those of BRS Hozan, Ito, and Caçador to susceptibility.

Study on culture of stable aerobic granular sludge

In this study, three reactors were established with anaerobic plug-flow times of 1.5 hours, 1 hour, and 0.5 hours. The results indicated that the anaerobic plug-flow time of 1 hour constructed favorable "feast- famine" period ratio, promoting the enrichment of microorganisms that stored and utilized the internal carbon source, such as Phosphate and Glycogen Accumulating Organisms (PAO and GAO). This resulted in the formation of granular sludge with both short granulation time and structural stability. In contrast, shortening the anaerobic feed time to 0.5 hours was detrimental to the growth of GAO, leading to slow granularization of aerobic sludge. The anaerobic influent time of 1.5 h leads to the shortening of starvation period and poor stability of particle structure.

From a long-term dynamic perspective: how should internal carbon pricing be implemented?

Internal carbon pricing has the potential to positively influence enterprises’ carbon emissions. However, the strategies for implementing internal carbon pricing for enterprises and internal organizations remain unclear. In this study, employing a differential game research methodology, we design three implementation strategies for internal carbon pricing from a dynamic time perspective. Through comparative research and numerical analysis of these three different strategies’ effects on the changes in enterprise carbon emission reduction and goodwill, we find that for both enterprises’ carbon emission reduction and goodwill, Model C (implementing secondary investment for internal carbon fee collection) is optimal when the proportion of internal organizational revenue allocation is high and the proportion coefficient of internal carbon fee collection is low. When the proportion coefficient of internal carbon fee collection meets certain conditions, it makes the total profit of system under model C (implementing secondary investment for internal carbon fee collection) larger than the other two strategies. Due to short-sighted behavior, both enterprises’ profits and carbon emissions gradually decrease, leading to the internal carbon prices of enterprises under the three strategies will approach a stable value.

Linear Extension of Carbaporphyrin Chromophores: Synthesis, Protonation, and Metalation of Anthro[2,3-b]carbaporphyrins: Evidence for 30π-Electron Aromatic Circuits in a Palladium(II) Complex.

Acid-catalyzed condensation of a naphtho[2,3-f]indane dialdehyde with a tripyrrane, followed by an oxidation step, afforded an anthro[2,3-b]-21-carbaporphyrin. The presence of a fused anthracene unit induced minor bathochromic shifts and did not significantly affect the aromatic characteristics of the carbaporphyrin core. Protonation led to the formation of a monocation with similar diatropic properties, but the dication generated in the presence of a large excess of trifluoroacetic acid had a weakened Soret band absorption and a broad absorption at 754 nm. Nucleus-independent chemical shift (NICS) calculations indicate that the dication is only weakly aromatic and possesses a 32-atom 30π electron delocalization pathway. Alkylation with methyl iodide and potassium carbonate gave a 22-methyl derivative that reacted with palladium(II) acetate to afford an aromatic palladium(II) complex. Upon heating, the methyl group migrated from the nitrogen to the internal carbon atom and the resulting complex exhibited diminished aromatic character. A comparison with related carbaporphyrin complexes without ring fusion or with benzo- or naphtho-fused units demonstrated that the diatropic character decreased with increasing conjugation. NICS calculations and anisotropy of induced current density (AICD) plots confirmed this trend and showed that the remaining aromatic properties of the anthrocarbaporphyrin complex were due to a 30π electron circuit that extends around the entire anthracene unit.

Design Criteria for Nanostructured Carbon Materials as Solid Contacts for Ion-Selective Sensors.

The ability to miniaturize ion-selective sensors that enable microsensor arrays and wearable sensor patches for ion detection in environmental or biological samples requires all-solid-state sensors with solid contacts for transduction of an ion activity into an electrical signal. Nanostructured carbon materials function as effective solid contacts for this purpose. They can also contribute to improved potential signal stability, reducing the need for frequent sensor calibration. In this Perspective, the structural features of various carbon-based solid contacts described in the literature and their respective abilities to reduce potential drift during long-term, continuous measurements are compared. These carbon materials include nanoporous carbons with various architectures, carbon nanotubes, carbon black, graphene, and graphite-based solid contacts. The effects of accessibility of ionophores, ionic sites, and other components of an ion-selective membrane to the internal or external carbon surfaces are discussed, because this impacts double-layer capacitance and potential drift. The effects of carbon composition on water-layer formation are also considered, which is another contributor to potential drift during long-term measurements. Recommendations regarding the selection of solid contacts and considerations for their characterization and testing in solid-contact ion-selective electrodes are provided.

How the implementation of internal carbon pricing impacts on carbon reduction: facilitating or hindering

How the implementation of internal carbon pricing impacts on carbon reduction: facilitating or hindering

Tandem Carbon Hollow Spheres with Tailored Inner Structure as Sulfur Immobilization for Superior Lithium–Sulfur Batteries

AbstractThe construction of lithium–sulfur battery cathode materials while simultaneously achieving high areal sulfur‐loading, adequate sulfur utilization, efficient polysulfides inhibition, rapid ion diffusion, etc. remains a major challenge. Herein, an internal regulatory strategy to fabricate the unique walnut‐like yolk–shell carbon flower@carbon nanospheres is presented (WSYCS) as sulfur hosts. The internal carbon flower, suitable cavity, and external carbon layer effectively disperse the insulate sulfur, accommodate volumetric expansion, and confine polysulfides, thus improving the performance of lithium–sulfur batteries. The finite element simulation method also deduces the enhanced Li+ diffusion and lithium–sulfur reaction kinetics. More importantly, WSYCS2 is grafted onto carbon fiber (CF) by electro‐spinning method to form a tandem WSYCS2@CF 3D film as a sulfur host for the free‐standing electrode. The corresponding battery exhibits an extremely high areal capacity of 15.5 mAh cm−2 with a sulfur loading of 13.4 mg cm−2. Particularly, the flexible lithium–sulfur pouch cell delivers a high capacity of 8.1 mAh cm−2 and excellent capacity retention of 65% over 800 cycles at a relatively high rate of 1C, corresponding to a calculated energy density of 539 Wh kg−1 and 591 Wh L−1. This work not only provides guidance for tailoring thick carbon/sulfur electrodes but also boosts the development of practical lithium–sulfur batteries.

Dual carbon confined MoS2 hierarchical microspheres as high-performance anode for sodium-ion batteries with superior cycling stability

Due to the growing demand in the energy market, sodium-ion batteries (SIBs) have garnered significant attention as potential energy storage devices for large-scale applications. However, the sluggish kinetics and significant volume expansion during cycling bring about the poor electrochemical behavior of SIBs. In this work, a dual carbon including internal hard carbon core and external N-doped carbon shell confined MoS2 hierarchical microspheres (HC@MoS2@NC) nanocomposites are prepared as anode for SIBs with superior cycling stability and good rate capability. The dual carbon confinement can improve the structural stability of MoS2. The dual carbon with good electronic conductivity ensures well battery rate capability of MoS2 anode. Meanwhile, the larger interlayer spacing of 10.09 Å caused by NC insertion make MoS2 store more Na+. As a consequence, the HC@MoS2@NC nanocomposite delivers a high capacity of 321 mAh g−1 at 0.1 A g−1 after 100 cycles. At large current density of 2 A g−1, a high capacity of 180 mAh g−1 can still be achieved after 1000 cycles. Even at larger current density of 5 A g−1, the capacity can still be kept at 162 mAh g−1 after 100 cycles.

A tripartite evolutionary game behavior analysis of the implementation strategy of the internal carbon pricing of enterprises under governments supervision

Internal Carbon Pricing (ICP) represents an innovative approach to carbon emission reduction. The implementation of the ICP involves enterprises and internal organizations, with its outcomes closely tied to government actions. In this study, a tripartite evolutionary game model comprising these subjects was constructed, and subsequent simulation analyses were conducted. The results revealed the following key findings: (1) When the combined total of carbon fees and governments' emission reduction subsidies surpasses the aggregate of carbon fees returned to internal organizations and ICP implementation costs, and when enterprises' revenues exceed governments' subsidies, all three parties will evolve towards ESS (1,1,1). This signifies that enterprises opt for the ICP, internal organizations actively reduce emissions, and governments engage in proactive regulation. (2) Reducing the cost of implementing ICP, increasing the carbon fee rebate ratio, raising governments' subsidies, and elevating the internal carbon price all contribute to promoting the attainment of the evolutionary game results ESS (1,1,1). However, it's important to note that higher governments' subsidies and carbon fee rebate ratios do not necessarily lead to a greater incentive for the three parties to reach the ESS(1,1,1). These findings provide a solid theoretical foundation for enterprises considering the implementation of the ICP in the future.

Acclimation of the Grapevine Vitis vinifera L. cv. Assyrtiko to Water Deficit: Coordination of Structural and Functional Leaf Traits and the Dynamic of Calcium Oxalate Crystals

Grapevine leaves contain abundant CaOx crystals located either within the mesophyll in the form of raphides, or in the bundle sheaths as druses. CaOx crystals function as internal carbon pools providing CO2 for a baseline level of photosynthesis, named “alarm photosynthesis”, despite closed stomata; thus, preventing the photoinhibition and the oxidative risk due to carbon starvation under adverse conditions. Structural and functional leaf traits of acclimated grapevine plants (Vitis vinifera L. cv. Assyrtiko) were investigated in response to water availability, in order to evaluate the dynamic functionality of CaOx. Leaf water potential, leaf area, leaf mass per area, stomatal properties, gas exchange parameters and performance index (PI) were decreased in leaves of vines acclimated to water deficit in comparison to the leaves of well-irrigated vines, although the chlorophyll fluorescence parameters showed that the operational efficiency of the photosystem II (PSII) photochemistry (Fv/Fm) did not change, indicating that the photosynthetic apparatus was not subjected to water stress. During the afternoon, more than half of the morning’s existing druses disappeared in the drought-acclimated leaves. Also, the raphides’ area of the drought-acclimated leaves was reduced more than that of the well-watered leaves. The substantial decomposition of druses under water deficit conditions compared to that of the raphides may have important implications for the maintenance of their different though overlapping roles. According to the results, it seems likely that, under water deficit conditions, a mechanism of “alarm photosynthesis” provides an additional tolerance trait in the leaves of Vitis vinifera cv. Assyrtiko; hence, leaf structure relates to function.

The spatial spillover effects and equity of carbon emissions of digital economy in China

The global economy is entering an era of digitalization and green development. While the digital economy has brought sustained growth to the economy, it has also raised concerns, particularly regarding carbon emissions. This study focuses on China's digital industry and utilizes an interregional input-output model to construct a carbon emission spillover-feedback effects model. It analyzes the transfer of carbon emission pressure between regions from the perspective of spatial spillovers and assesses the equity of carbon emissions from the digital industry. The research findings indicate:1. The hidden carbon emissions of the digital industry mainly include internal and external carbon spillover emissions.2. There is significant spatial heterogeneity in the carbon spillover emissions, with eastern and coastal developed regions being the primary areas of carbon emissions spillover, while the northwestern and central regions bear the burden of carbon emissions from other areas.3. The digital industry primarily experiences carbon emission spillovers between industries with resource and material-intensive characteristics.4. The economic efficiency and equity of carbon emissions from the digital industry exhibit a negative correlation with the level of economic development, and an overall declining trend is observed. In summary, recognizing the mechanisms and pathways of interregional carbon emission transfer in the development of the digital economy is crucial for avoiding the exacerbation of interregional environmental pressure, reshaping resource trade relationships, and achieving the goals of carbon peak and carbon neutrality.

The external/internal sources and sinks of greenhouse gases (CO2, CH4, N2O) in the Pearl River Estuary and adjacent coastal waters in summer

Estuary acts as a hotspot of greenhouse gases (GHGs, including CO2, CH4 and N2O) to the atmosphere. However, the GHGs budgets, including input/output fluxes through interfaces and biogeochemical source/sink processes in water columns, of the estuarine systems are still not well constrained due to the lacking of comprehensive observational data. Here, we presented the spatial distributions of GHGs of surface/bottom water and sediment porewater along the Pearl River Estuary (PRE) and adjacent region during summertime. The incorporation of the monitoring for the sediment-water interface (SWI) with these of the water-air interface (WAI) allows us to close the budget revealing additional information of internal consumption/production processes of the three GHGs. The oversaturated CO2 (481–7573 μatm), CH4 (289–16,990 %) and N2O (108–649 %) in surface water suggested PRE is a significant GHGs source to the atmosphere, in which CO2 is the major contributor accounting for 90 % of total global warming potential (GWP), leaving 2.8 % from CH4, and 7.2 % from N2O. Addition to the river input, the SWI releases GHGs to the overlying water with fluxes of 3.5 × 107, 10.8 × 104 and 0.7 × 104 mol d−1 for CO2, CH4 and N2O, respectively. Although all three GHGs exhibited emission to the atmosphere, our mass balance calculation showed that 16.9× 107 mol d−1 of CO2 and 1.0 × 104 mol d−1 of N2O were consumed, respectively, inside the estuary water body, while extra-production (13.8 × 104 mol d−1) of CH4 was demanded in the water body to support its output flux. This is the first experiment quantitatively assessing the importance of internal carbon and nitrogen biogeochemical processes in the PRE. Our finding is of guiding significance to constrain the GHGs budget and draw up realistic pathways for modeling works of GHGs prediction.

A DEA-based model for grouped internal carbon pricing: An analysis of a large coal producer

As a strategic lever, internal carbon pricing allows enterprises to cope with potential climate-related risks and motivate their low-carbon transformation. But internal carbon pricing, still in its early exploratory stage, lacks standard criteria for optimization. The traditional goal of cost minimization or profit maximization is not directly applicable to internal carbon pricing because internal payment for carbon emissions does not affect enterprises' aggregated costs or profits. How to optimize internal carbon prices to reduce carbon emissions more efficiently becomes an important issue. This study proposed a grouped internal carbon pricing method considering both internal carbon pricing and comprehensive efficiency. We found that there exists an optimal partition of internal units with corresponding differentiated carbon prices. Compared with other internal carbon pricing methods, the average efficiency of differentiated carbon pricing was significantly higher than the average efficiency of uniform carbon pricing. We then applied the method to a large coal producer with 16 subdivisions in China. The results showed that if the enterprise adopted the grouped internal carbon pricing under its current technology level, the carbon emissions would reach an optimal level, and its comprehensive efficiency would be significantly improved.