High Efficiency Carbon Research Articles

Preparation of highly effective carbon adsorbents based on high-moor peat from the European North of Russia

The study of active coals obtained from high-moor peat of the European North of Russia was conducted by method of thermochemical activation with NaOH with various types of pre-treatment (debituminization and pre-hydrolysis). Based on the results of the low-temperature adsorption of nitrogen, the derived active coals belong to the adsorbents in which the structure of the micro-agents predominates. The specific surface of the coal pores reaches 2330 m2/g, the total volume of pores – 1.44 cm3/g. It has been determined that the introduction of the pre-hydrolysis stage makes it possible to increase significantly the yield of active coals. For initial peat samples, the growth is 28%; for debituminized – 97%, moreover it significantly improve its sorption characteristics. It has been shown that weakly decomposed peat of the European North of Russia can be used as raw material for producing high-efficiency carbon microporous adsorbents.

MMD-TSC: An Adaptive Multi-Objective Traffic Signal Control for Energy Saving with Traffic Efficiency

Reducing traffic energy consumption is crucial for smart cities, and vehicle carbon emissions are a key energy indicator. Traffic signal control (TSC) is a useful method because it can affect the energy consumption of vehicles on the road by controlling the stop-and-go of vehicles at traffic intersections. However, setting traffic signals to reduce energy consumption will affect traffic efficiency and this is not in line with traffic management objectives. Current studies adopt multi-objective optimization methods with high traffic efficiency and low carbon emissions to solve this problem. However, most methods use static weights, which cannot adapt to complex and dynamic traffic states, resulting in non-optimal performance. Current energy indicators for urban transportation often fail to consider passenger fairness. This fairness is significant because the purpose of urban transportation is to serve people’s mobility needs not vehicles. Therefore, this paper proposes Multi-objective Adaptive Meta-DQN TSC (MMD-TSC), which introduces a dynamic weight adaptation mechanism to simultaneously optimize traffic efficiency and energy saving, and incorporates the per capita carbon emissions as the energy indicator. Firstly, this paper integrates traffic state data such as vehicle positions, velocities, vehicle types, and the number of passengers and incorporates fairness into the energy indicators, using per capita carbon emissions as the target for reducing energy consumption. Then, it proposes MMD-TSC with dynamic weights between energy consumption and traffic efficiency as reward functions. The MMD-TSC model includes two agents, the TSC agent and the weight agent, which are responsible for traffic signal adjustment and weight calculation, respectively. The weights are calculated by a function of traffic states. Finally, the paper describes the design of the MMD-TSC model learning algorithm and uses a SUMO (Simulation of Urban Mobility) v.1.20.0 for traffic simulation. The results show that in non-highly congested traffic states, the MMD-TSC model has higher traffic efficiency and lower energy consumption compared to static multi-objective TSC models and single-objective TSC models, and can adaptively achieve traffic management objectives. Compared with using vehicle average carbon emissions as the energy consumption indicator, using per capita carbon emissions achieves Pareto improvements in traffic efficiency and energy consumption indicators. The energy utilization efficiency of the MMD-TSC model is improved by 35% compared to the fixed-time TSC.

Assessing the aerobic/anoxic enrichment efficiency at different C/N ratios: pilot scale polyhydroxyalkanoates production from waste activated sludge

Polyhydroxyalkanoates (PHA) can be produced using fermentation products of an excess sewage sludge fermentation process. An efficient method to enrich a PHA-producing community is an aerobic-feast/anoxic-famine enrichment strategy. The effect of different carbon to nitrogen (C/N) feed ratios of 1, 2 and 3.5 g COD/g N on the process performance was studied. The study was executed on a pilot plant scale using fermented waste activated sludge as the organic carbon source. The system's performance was monitored in terms of removing contaminants, producing PHA, and reducing N2O emissions. The results indicated that a lower C/N ratio results in lower PHA production, with PHA content in the sludge of 20, 24 and 36 % w/w for C/N ratios of 1, 2 and 3.5 g COD/g N, respectively. At the lowest C/N ratio, the highest nitrite accumulation rate (77%), nitrification efficiency (89%) and denitrification efficiency (89%) were observed, but the N2O production was also the highest (0.77 mg N2O-N/L). The long-term comprehensive monitoring carried out in this study revealed high carbon and ammonia removal efficiencies (never below 80%) despite the C/N shifts and high COD and ammonia concentrations. At the same time, the system showed relatively low PHA production and high environmental impact in terms of high gaseous N2O emission. These findings question the sustainability of the aerobic-feast/anoxic-famine enrichment strategy for PHA production in full-scale plants.

Acid-Stable Cu Cluster Precatalysts Enable High Energy and Carbon Efficiency in CO2 Electroreduction.

The electrochemical reduction of CO2 in acidic media offers the advantage of high carbon utilization, but achieving high selectivity to C2+ products at a low overpotential remains a challenge. We identified the chemical instability of oxide-derived Cu catalysts as a reason that advances in neutral/alkaline electrolysis do not translate to acidic conditions. In acid, Cu ions leach from Cu oxides, leading to the deactivation of the C2+-active sites of Cu nanoparticles. This prompted us to design acid-stable Cu cluster precatalysts that are reduced in situ to active Cu nanoparticles in strong acid. Operando Raman and X-ray spectroscopy indicated that the bonding between the Cu cluster precatalyst ligand and in situ formed Cu nanoparticles preserves a high density of undercoordinated Cu sites, resulting in a C2H4 Faradaic efficiency of 62% at a low overpotential. The result is a 1.4-fold increase in energy efficiency compared with previous acidic CO2-to-C2+ electrocatalytic systems.

Anionic Ionomer: Released Surface-Immobilized Cations and an Established Hydrophobic Microenvironment for Efficient and Durable CO2-to-Ethylene Electrosynthesis at High Current over One Month.

Electrosynthesis of multicarbon products, such as C2H4, from CO2 reduction on copper (Cu) catalysts holds promise for achieving carbon neutrality. However, maintaining a steady high current-level C2H4 electrosynthesis still encounters challenges, arising from unstable alkalinity and carbonate precipitation caused by undesired ion migration at the cathode under a repulsive electric field. To address these issues, we propose a universal "charge release" concept by incorporating tiny amounts of an oppositely charged anionic ionomer (e.g., perfluorinated sulfonic acid, PFSA) into a cationic covalent organic framework on the Cu surface (cCOF/PFSA). This strategy effectively releases the hidden positive charge within the cCOF, enhancing surface immobilization of cations to impede both outward migration of generated OH- and inward migration of cations, inhibiting carbonate precipitation and creating a strong alkaline microenvironment. Meanwhile, the ionomer's hydrophobic chains create a hydrophobic environment within the cCOF, facilitating efficient gas transport. In situ characterizations and theoretical calculations demonstrate that the cCOF/PFSA catalyst establishes a hydrophobic strong alkaline microenvironment, optimizing the adsorption strength and configuration of *CO intermediates to promote the C2H4 formation. The optimized catalyst achieves a 70.5% Faradaic efficiency for C2H4 with a partial current density over 470 mA cm-2. Notably, it delivers a high single-pass carbon efficiency of 96.5% for CO2RR and sustains an exceptional stability over 760 h. When implemented in a large-area MEA electrolyzer and a 5-cell MEA stack, the system achieves an industrial current of 15 A and continuous C2H4 production exceeding 19 mL min-1, marking a significant step toward industrial feasibility in CO2RR-to-C2H4 conversion.

A Solid-State Electrolyte Facilitates Acidic CO2 Electrolysis without Alkali Metal Cations by Regulating Proton Transport.

Electrochemical CO2 reduction (CO2R) in acidic media provides a pathway to curtail CO2 losses by suppressing the formation of (bi)carbonates. In such systems, a high concentration of alkali metal cations is necessary for mitigating the proton-rich environment and suppressing the competing hydrogen evolution reaction. However, a high cation concentration also promotes salt precipitation within the gas diffusion layer, resulting in poor system durability. Here, we resolve this conundrum by replacing the liquid catholyte with a solid-state proton conductor to regulate H+ transport. This is postulated to allow for a locally alkaline environment at the cathode, enabling selective CO2R even without alkali metal cations. We show that this strategy is effective over a broad range of catalyst systems. For instance, we achieve an 87% CO faradaic efficiency (FE) at 300 mA/cm2 using a composite nanoporous Au and single-atom Ni catalyst, with 0.25 M H2SO4 as the anolyte. Stable operation over 110 h and a high single-pass carbon efficiency of 82.8% were also successfully demonstrated. Importantly, we find that this solid-state system is also particularly effective at converting dilute feedstock (5% CO2) with a CO FE of 47.7%, a factor of 16.4 times higher than a conventional system. Our results introduce a simple yet effective design approach for developing efficient acidic CO2R electrolyzers.

Large-area and high-efficiency carbon nanotube/silicon heterojunction solar cells enabled by self-similar fiber electrodes and solid-state gel electrolytes

Carbon nanotube/silicon (CNT/Si) Van der Waals heterojunction solar cells have attracted increasing attention due to their low-cost, easy-fabrication process and potential use in next generation photovoltaics. Herein, we reported a high-performance and large-area solar cell fabricated using high-quality CNT films, self-similar CNT fibers and solid-state gel electrolytes. The power conversion efficiency of the fabricated device reached 13.1 % in an active area of 1 cm2, which is much higher than that of the pristine CNT/Si device (7.19 %). In this system, small-bundled and carbon-welding structure at inter-tube junctions enable the CNT film with excellent conductivity. The CNT fiber electrodes were adopted as front contact grids to further reduce the resistance of the CNT film owing to their high conductivity and self-similar microstructure. The solid-state gel electrolyte functions as a p-type dopant to enhance the conductivity of CNTs and the built-in potential at the heterojunction, meanwhile its antireflection property contributes to a significant improved photocurrent of the solar cells. This simple and effective way provides a facile route for developing high-performance, large-area CNT/Si Van der Waals heterojunction solar cells.

Polyelectrolyte Additive-Modulated Interfacial Microenvironment Boosting CO2 Electrolysis in Acid.

Acidic CO2 electrolysis offers a promising strategy to achieve high carbon utilization and high energy efficiency. However, challenges remain in suppressing the competitive hydrogen evolution reaction (HER) and improving product selectivity. High concentrations of potassium ions (K+) can suppress HER and accelerate CO2 reduction, but they still inevitably suffer from salt precipitation problems. In this study, we demonstrate that the sulfonate-based polyelectrolyte, polystyrene sulfonate (PSS), enables to reconstruct the electrode-electrolyte interface to significantly enhance the acidic CO2 electrolysis. Mechanistic studies reveal that PSS induces high local K+ concentrations through electrostatic interaction between PSS anions and K+. In situ spectroscopy reveals that PSS reshapes the interfacial hydrogen-bond (H-bond) network, which is attributed to the H-bonds between PSS anions and hydrated proton as well as the steric hindrance of the additive molecules. This greatly weakens proton transfer kinetics and leads to the suppression of undesirable HER. As a result, a Faradaic efficiency of 93.9% for CO can be achieved at 250 mA cm-2, simultaneous with a high single-pass carbon efficiency of 72.2% on commercial Ag catalysts in acid. This study highlights the important role of the electrode-electrolyte interface induced by polyelectrolyte additives in promoting electrocatalytic reactions.

β-Ketoenamine Porous Organic Polymers for High-Efficiency Carbon Dioxide Adsorption and Separation.

To mitigate the greenhouse effect, a number of porous organic polymers (POPs) has been developed for carbon capture. Considering the permanent quadrupole of symmetrical CO2 molecules, the integration of electron-rich groups into POPs is a feasible way to enhance the dipole-quadrupole interactions between host and guest. To comprehensively explore the effect of pore environment, including specific surface area, pore size, and number of heteroatoms, on carbon dioxide adsorption capacity, we synthesized a series of microporous POPs with different content of β-ketoenamine structures via Schiff-base condensation reactions. These materials exhibit high BET specific surface areas, high stability, and excellent CO2 adsorption capacity. It is worth mentioning that the CO2 adsorption capacity and CO2/N2 selectivity of TAPPy-TFP reaches 3.87 mmol g-1 and 27. This work demonstrates that the introduction of β-ketoenamine sites directly through condensation reaction is an effective strategy to improve the carbon dioxide adsorption performance of carbon dioxide.

Integrated nutrient management on oat + grasspea intercropping system: an evaluation of system productivity, economics, energetics and carbon footprint

A field investigation took place at Central Research Farm of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India during winter seasons of 2020–21 and 2021–22 with the aim to evaluate system productivity, economics, energetics and carbon footprint (CF) of oat + grasspea intercropping systems under different integrated nutrient managements (INM). The experiment was executed in split-plot design with 4 cropping systems in main plots and 4 levels of nutrient management in sub plots. The 3:3 intercropping system of oat + grasspea ensured highest system productivity, whereas sole grasspea stood best in terms of economics, energetics and environment safety by lowering CF. Notably, INM involving 75% N through urea + 25% N through vermicompost registered significantly higher system productivity in case of 3:3 oat + grasspea intercropping system (CS4N3) (18.77 q ha−1). Further, this intercropping system yielded high economic profitability (net return: US$ 430.4 ha−1, benefit–cost ratio: 1.71) as well as energy indices (energy output: 71179.1 MJ ha-1, net energy gain: 60352.0 MJ ha−1, energy ratio: 6.57 and energy profitability: 5.57). CF was also found relatively low under CS4N3 (Yield scaled CF: 62.2 kg CO2-e q−1). Furthermore, high carbon efficiency (7.92) and carbon sustainability index (6.92) were also exhibited by CS4N3 as it produced maximum carbon output (1801.2 kg ha−1). In conclusion, the 3:3 oat + grasspea intercropping system using INM can be viable option to ensure economic and energy viability and minimize greenhouse gas emissions without compromising system productivity. Particularly, this intercropping system combined with 75% N through urea + 25% N through vermicompost as INM option can be recommended for the cereal and legume growers of India, specifically under intensive cropping scenario.

Strain and model development for auto- and heterotrophic 2,3-butanediol production using Cupriavidus necator H16

The production of platform chemicals from renewable energy sources is a crucial step towards a post-fossil economy. This study reports on the production of acetoin and 2,3-butanediol heterotrophically with fructose as substrate and autotrophically from CO2 as carbon source, H2 as electron donor and O2 as electron acceptor with Cupriavidus necator. In a previous study, the strain was developed for the production of acetoin with high carbon efficiency. Acetoin can serve as a precursor for the synthesis of 2,3-butanediol by the integration of a butanediol dehydrogenase. In this study, different plasmid backbones and butanediol dehydrogenases were evaluated regarding efficiency for CO2-based 2,3-butanediol production. The developed strain utilizes the pBBR1 plasmid bearing a 2,3-butanediol dehydrogenase from Enterobacter cloacae and is characterized by 2,3-butanediol as the main product and a heterotrophic total product yield of 88.11%, an autotrophic volumetric productivity of 39.45 mg L−1 h−1, a total product carbon yield of 81.6%, an H2 efficiency of 33.46%, and a specific productivity of 0.016 g product per gram of biomass per hour. In addition, a mathematical model was developed to simulate the processes under these conditions. With this model, it was possible to calculate productivities and substrate usage at distinct time points of the production processes and calculate productivities and substrate usage with high resolution which will be useful in future applications.

Renewable methanol production based on in situ synergistic utilization of excavated waste and landfill gas: life cycle techno-environmental-economic analysis

Excavated waste (EW) and landfill gas (LFG), as the two main landfill products, are essential objects of Enhanced landfill mining (ELFM). In this study, for the in situ synergistic utilization of LFG and the residue-derived fuel (RDF) from EW, an RDF-LFG to methanol (MeOH) unit with high exergy efficiency and low carbon emission is proposed. Then, to evaluate the environmental impacts and economic feasibility comprehensively, the life cycle assessment (LCA) and life cycle cost (LCC) are conducted on the EW-LFG to MeOH system based on the Aspen Plus simulation data of the RDF-LFG to MeOH unit. The system using EW landfilled in 2005 & 2015 as feedstocks are named Scheme A & B, respectively. The results show that both schemes have an exergy efficiency of more than 70 %. Regarding environmental impacts, RDF-LFG to MeOH, EW pretreatment, Storage and transport of products, and EW Mining are the main contributors. This study pays particular attention to global warming (GW) potential. The direct and indirect carbon emission of the RDF-LFG to MeOH unit are about 35 and 650 kg CO2 eq/ton MeOH, and the life-cycle GW of the EW-LFG to MeOH system is between 707 to 874 kg CO2 eq/ton MeOH. Levelized cost (LC) and levelized profit (LP) are about 452 $/ ton MeOH and 94 $/ton MeOH. With the transformation of the power grid, the decrease in carbon emission factor of power grids can improve both the environmental, and economic performance of the EW-LFG to MeOH system. Methanol selling price, carbon tax and electricity cost are the major sensible factors to the economic feasibility.

Revisiting Solar Energy Flow in Nanomaterial-Microorganism Hybrid Systems.

Nanomaterial-microorganism hybrid systems (NMHSs), integrating semiconductor nanomaterials with microorganisms, present a promising platform for broadband solar energy harvesting, high-efficiency carbon reduction, and sustainable chemical production. While studies underscore its potential in diverse solar-to-chemical energy conversions, prevailing NMHSs grapple with suboptimal energy conversion efficiency. Such limitations stem predominantly from an insufficient systematic exploration of the mechanisms dictating solar energy flow. This review provides a systematic overview of the notable advancements in this nascent field, with a particular focus on the discussion of three pivotal steps of energy flow: solar energy capture, cross-membrane energy transport, and energy conversion into chemicals. While key challenges faced in each stage are independently identified and discussed, viable solutions are correspondingly postulated. In view of the interplay of the three steps in affecting the overall efficiency of solar-to-chemical energy conversion, subsequent discussions thus take an integrative and systematic viewpoint to comprehend, analyze and improve the solar energy flow in the current NMHSs of different configurations, and highlighting the contemporary techniques that can be employed to investigate various aspects of energy flow within NMHSs. Finally, a concluding section summarizes opportunities for future research, providing a roadmap for the continued development and optimization of NMHSs.

Comparative techno-economic assessment of methanol production via directly and indirectly electrified biomass gasification routes

The sustainable production of chemicals and fuels is a major challenge in order to reduce greenhouse gas emissions and reduce the usage of fossil resources. Biomass gasification with a subsequent conversion of the syngas to methanol is an established route. The direct (electrical resistance heating) or indirect (H2 production via water electrolysis and addition to process) electrification of this route with utilization of renewably produced electricity can improve the effective utilization of biomass which is a scarce resource. Starting with a base case (Biomass-to-MeOH), 10 scenarios with different types and points of electrification are modelled in Aspen Plus to generate mass and energy balances. Based on the generated data, the processes are compared in terms of efficiency, economics, and CO2 emissions.The electrification ratios range from 0.12 for the Biomass-to-MeOH process to 1.31. Electrification can increase the carbon efficiency from 43 % for the Biomass-to-MeOH process to up to 95 % while the energy efficiency ranges from 54.6 % to 60.3 % with 54.7 % for the Biomass-to-MeOH process. The levelized cost of methanol ranges from 642 to 795 €/t. Lowest LCOM are reached for direct electrification of the gasifier or reformer. A flexible operation of the electrified process shows a higher sensitivity on the levelized cost for scenarios with high degree of electrification. The marginal emission factor for the used electricity ranges from 1761 to 352 g CO2/kWh to reach equal emissions than the fossil equivalent. Sustainable methanol can be produced with the electrified processes. Especially direct electrification can improve the efficiency and lower cost in comparison to indirect electrification. A combination of both types of electrification is advised if a high product yield and carbon efficiency are desired.

Research on the Assistance and Countermeasures of Digital Empowerment in the Environment of Carbon Emission Reduction

In the current global context, what carbon reduction challenges do other nations face, and how are they leveraging digital technologies to facilitate carbon emission mitigation? Under the circumstances where China currently ranks first in the world in terms of total carbon emissions, how can the country, in light of its unique situation, employ digitalization more effectively to aid in realizing efficient carbon reduction measures? Within this framework, starting from the critical and challenging aspects of domestic carbon emissions, this paper contemplates the ways in which contemporary digital tools can be harnessed to implement high-efficiency carbon reduction strategies tailored to the national context. In the acceleration of the development of the digital economy, the role of digital technology in reducing CO2 emissions is becoming increasingly apparent. The traditional energy interconnection network has long been integrated with the traditional energy industry, but how to apply the advantages of network technology to the energy industry, so that energy has new digital characteristics and network thinking has become the energy industry urgently. To this end, this paper mainly focuses on the project research on digital empowerment in the environment of carbon emission reduction, and will mainly consider the key aspects of domestic carbon emission accounting for a large proportion based on the current situation at home and abroad and the research and development status of digital combined carbon emission reduction. In view of these aspects, the feasibility of implementing the digital assistance scheme was discussed, such as focusing on the domestic power system and aiming at the interaction and mutual drive relationship between the power system and the economic and social system; Factory operation planning, transportation industry, with data sharing open system and new format and new model innovation as the guarantee, overall promotion of comprehensive transportation digital transformation and intelligent upgrading; The building materials industry and the discussion of digitalization help build smart parks and improve the level of park informatization. Reduce carbon emissions and create favorable conditions for the subsequent domestic "zero carbon" and "carbon neutral" goals.

Cobalt(II) tetraphenylporphyrin trapped in the pores of Cu2O to enhance the C2+ selectivity towards acidic CO2 electroreduction

Achieving the high selectivity of multicarbon (C2+) products during the acidic CO2 electroreduction remains a formidable challenge due to the serious hydrogen evolution reaction. Herein we report a Cu-based tandem catalyst by implanting molecular cobalt(II) tetraphenylporphyrin (CoTPP) into a porous Cu2O (Cu2O-CoTPP) for improving the C2+ selectivity in acidic media. Specially, CoTPP, as a CO-selective catalyst, is predominantly trapped in the nanopores of Cu2O with the assistance of negative-pressure ultrasonic. The CO2-CO and CO-C2+ tandem catalysis on Cu2O-CoTPP, cooperating with the pore confinement effect of porous Cu2O, boosts the local CO concentration and *CO coverage on Cu sites, evidenced by in-situ Raman spectra and finite element simulations. As a result, Cu2O-CoTPP attains a C2+ Faradaic efficiency of 91.2 % at an industrial-level current density of 800 mA/cm2 in an acidic environment (pH = 1.9), higher than the one (70.6 %) on pristine Cu2O. Meanwhile, such a tandem catalyst obtains a high single-pass carbon efficiency of 52.6 % and the good catalytic stability of at least 20 h. This study offers a spatially-confined Cu-based tandem catalyst for selective C2+ production, presenting the promising application in acidic environments.

Selective CO2 hydrogenation to liquid fuels over Na-decorated FeMgMnOx catalyst with high carbon efficiency

Direct synthesis of liquid fuels (C5+ hydrocarbons) through CO2 hydrogenation has attracted considerable interest. However, it is plagued by high selectivity of C1 by-products (CO and CH4) and low reaction activity. Herein, we report that Na-decorated Fe catalysts promoted by combination of Mg and Mn and investigate their synergistic effect in the catalytic CO2 hydrogenation reaction. The optimized amounts of promoters result in a significant improvement in the catalytic performance of NaFe2O3. The CO2 conversion increases by 1.6-fold, while the total selectivity of CO and CH4 is suppressed to below 21.3 %. The characteristic results reveal the enhanced surface alkalinity and electron transfer favor CO2 adsorption and tuned the local H/C ratio in the vicinity of iron species, thus remarkably promoting the carbon chain growth and limiting the production of C1 products. This study offers a promising approach to modulating the metal electronic environment and improving carbon efficiency for CO2 hydrogenation reactions.

High-efficient carbon dioxide-to-formate conversion on Bi5O7NO3 by tuning the exposure of crystal plane during reconstruction in electrolysis

The electrochemical conversion of carbon dioxide into formic acid offers an effective approach for utilizing carbon dioxide resources. Bismuth (Bi)-based catalysts have garnered significant attention in this field. However, designing high-performance Bi-based catalysts is challenging due to difficulties in accurately adjusting the reconstruction of such catalysts during electrolysis. In this study, we reported that nitrate ions positively influence the reconstruction of Bi5O7NO3 (BON), thereby outperforming Bi2O3 during ECO2RR. BON attained a Faraday efficiency of formate (FEHCOOH) and partial current density of 95.3 % and 25.1 mA/cm2 at −0.9 V vs RHE, respectively, surpassing the performance of Bi2O3 (90.2 % and 15.4 mA/cm2). The layered structure of BON mitigates Bi agglomeration during electrolysis, thus providing a large number of active sites. The presence of nitrate ions promotes exposure to abundant Bi(110) and Bi(015), whereas only the Bi(012) plane forms in Bi2O3 during electrolysis. In-situ ATR FTIR results indicate that both BON and Bi2O3 follow the same pathway for formate formation. Nevertheless, the high-index planes (015) cause the Bi derived from BON to remain in an electron defect state, which increases the adsorption of *CO2. In addition, Bi(110) plane has effectively lower the energy barriers for *OCHO production than Bi(012) plane. The Bi(015) and Bi(110) planes enhance the adsorption of *CO2 intermediates and reduce the energy barrier for *OCHO formation, respectively, which contributes to the improved ECO2RR activity of BON.

Energy Budgeting and Economic Analysis of Cowpea Varieties under Rainfed Condition

Background: Cowpea is a versatile leguminous pulse crop that exhibits resilience to drought and adapts well to various climates. It serves multiple purposes and can be enjoyed both in its raw form and as a grain pulse. Various studies established that cowpea has the potential vegetable crops with nitrogen fixation capacity. Thus, the study of environmentally safety and clean production of cowpea for better crop yield along with energy use efficiency and carbon budgeting for sustainable crop production is an important issue for the upcoming future. Methods: The present study was carried out at the experimental farm of Krishi Vigyan Kendra-Sepahijala, Latiacherra, Tripura under CAU (I) on 2022 and 2023 with three high yielding cowpea varieties (Kashi Kanchan, Kashi Gauri and Kashi Unnati). The design followed in the experiment adhered to a Randomized block design (RBD) with five replications. Result: Experiments result revealed that Kashi Kanchan perform outstanding by showing maximum pod yield. In the context of energy equivalent and Carbon budgeting, Kashi Kanchan is showing high energy use efficiency (45.01) and high carbon efficiency (1.59).

An evaluation of energy and carbon budgets in diverse cropping systems for sustainable diversification of rainfed uplands in India's eastern hill and plateau region

With increasing cost and use of energy in agriculture, the traditional practice of mono-cropping of rice in upland is neither sustainable nor eco-friendly. It is necessary to identify crop diversification options with high energy efficiency, productivity, and low global warming potential (GWP). In this experiment, an inclusive system analysis was accomplished for 3 years (2016–2019) of five mono-cropping production (MCP) systems namely rice (R), finger millet (FM), black gram (BG), horse gram (HG), pigeon pea (PP), and four intercropped systems viz. R+BG, R+HG, FM+ BG, and FM + HG. The key objective was to evaluate the flow of energy, carbon balance, and GWP of these varied production systems. Puddled rice was recorded as an energy-exhaustive crop (27,803 MJ ha−1), while horse gram was noted to have the lowest energy use (26,537 MJ ha−1). The total energy output from pigeon pea (130,312 MJ ha−1) and diversified intercropped systems (142,135 MJ ha−1) was 65.3% and 80.3% higher than mono-cultured systems, respectively. Rice and rice-based intercropping production systems showed higher carbon footprints (1,264–1,392 kg CO2 eq. ha−1). Results showed that R+BG and R+HG were the most energy-efficient production systems, having higher energy ratio (5.8 and 6.0), higher carbon efficiency (7.41 and 8.24), and carbon sustainability index (6.41 and 7.24) as against 3.30, 3.61, and 2.61 observed under sole cropping production systems. On average, rice and rice-based production systems had 7.4 times higher GWP than other production systems. In productivity terms, pigeon pea and FM+HG had higher rice equivalent yields of 8.81 and 5.79 t ha−1 and benefit-cost ratios of 2.29 and 1.87, respectively. Thus, the present study suggests that pigeon pea and finger millet-based intercropping systems were the most appropriate crop diversification options for the rainfed upland agro-ecosystem of the eastern region of India.