CO Ratio Research Articles

Dual Metal Sites Coengineered Graphitic Carbon Nitride as Green Electrocatalyst for Highly Selective Overall Water Splitting—A Sustainable Approach

The development of efficient, low‐cost, non‐noble metal‐oxide‐based nanohybrid materials for overall water splitting is a critical strategy for enhancing clean energy use and addressing environmental issues. In this study, an interfacial engineering strategy for the development of bimetallic Co–Ni nanoparticles on graphitic carbon nitride (g‐C3N4) using ultrasonication followed by coprecipitation is conveyed. These nanoparticles demonstrate high efficacy as bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline conditions. Co–Ni nanoparticles on graphitic carbon nitride demonstrate an increased surface area via ultrasonication and subsequent coprecipitation. The g‐C3N4 combined with Co–Ni nanoparticles leads to the development of bifunctional catalysts that exhibit significant efficiency in both HER and OER, and their interfacial properties are investigated for the first time. The chemical composition and morphology of g‐C3N4 integrated with Co–Ni nanoparticles significantly influence the modulation of redox‐active sites and the facilitation of electron transfer, resulting in improved splitting efficiency. The interactions between the Co–Ni bimetal and g‐C3N4 demonstrate exceptional electrochemical performance for water splitting. Consequently, the 20% 20–Co–Ni–graphitic carbon nitride electrode demonstrated superior HER performance, comparable to the other electrodes. In the results, it is indicated that an increased molar ratio of Co and Ni incorporated in graphitic carbon nitride significantly improves HER performance.

CH4 and CO emission estimates for megacities: deriving enhancement ratios of CO2, CH4, and CO from GOSAT-2 observations

Abstract Enhancement ratios among trace gases co-emitted by combustion of fossil fuels vary with emission sources and their combustion efficiency. We used column-averaged dry-air mole fractions of carbon dioxide (XCO2), methane (XCH4), and carbon monoxide (XCO) from the Greenhouse gases Observing SATellite-2 (GOSAT-2), a unique satellite that observes them simultaneously with the same field of view, to derive the enhancement ratios (ΔXCO/ΔXCO2, ΔXCO/ΔXCH4, and ΔXCH4/ΔXCO2) for the 40 most populous cities in the world. These enhancement ratios were used to evaluate the Emissions Database for Global Atmospheric Research (EDGAR). For cities where the difference in the 2015 EDGAR CO emissions between the latest versions (v6.1 and v5.0) was 30% or less, the GOSAT-2 ΔXCO/ΔXCO2 ratios and EDGAR (v6.1/v7.0) CO/CO2 emission ratios were in good agreement (correlation coefficient of 0.65). For ~70% of the cities where the difference of CO emissions exceeded 30%, the EDGAR CO/CO2 emission ratios using v6.1 CO emissions were in better agreement with the GOSAT-2 ΔXCO/ΔXCO2 ratios than those using v5.0 CO emissions, indicating that v6.1 CO emissions were improved over v5.0 emissions. However, for the remaining cities, the version upgrade may have reduced the CO emissions too much. The CH4 and CO emissions for each city were then estimated from the ΔXCH4/ΔXCO2 and ΔXCO/ΔXCO2 ratios, respectively, by reference to the CO2 emissions from the Open-data Inventory for Anthropogenic CO2 (ODIAC) or EDGAR. Compared to our estimates using the ODIAC (EDGAR) CO2 emissions, the EDGAR v7.0 CH4 and v6.1 CO emissions were underestimated for 74% (57%) and 76% (53%), respectively, of all cities where results were available. For several cities where emissions were estimated using in situ observations and ground-based remote sensing observations, our results were in reasonable agreement with these results. The implication is that satellite-derived enhancement ratios can provide informative constraints on anthropogenic emissions in megacities.

Dry Reforming of Methane (DRM) over Hydrotalcite-Based Ni-Ga/(Mg, Al)Ox Catalysts: Tailoring Ga Content for Improved Stability

Dry reforming of methane (DRM) is a promising way to convert methane and carbon dioxide into syngas, which can be further utilized to synthesize value-added chemicals. One of the main challenges for the DRM process is finding catalysts that are highly active and stable. This study explores the potential use of Ni-based catalysts modified by Ga. Different Ni-Ga/(Mg, Al)Ox catalysts, with various Ga/Ni molar ratios (0, 0.1, 0.3, 0.5, and 1), were synthesized by the co-precipitation method. The catalysts were tested for the DRM reaction to evaluate their activity and stability. The Ni/(Mg, Al)Ox and its Ga-modified Ni-Ga/(Mg, Al)Ox were characterized by N2 adsorption–desorption, Fourier Transform Infrared Spectroscopy (FTIR), H2-temperature-programmed reduction (TPR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Raman techniques. The test of catalytic activity, at 700 °C, 1 atm, GHSV of 42,000 mL/h/g, and a CH4: CO2 ratio of 1, revealed that Ga incorporation effectively enhanced the catalyst stability. Particularly, the Ni-Ga/(Mg, Al)Ox catalyst with Ga/Ni ratio of 0.3 exhibited the best catalytic performance, with CH4 and CO2 conversions of 66% and 74%, respectively, and an H2/CO ratio of 0.92. Furthermore, the CH4 and CO2 conversions increased from 34% and 46%, respectively, when testing at 600 °C, to 94% and 96% when the catalytic activity was operated at 850 °C. The best catalyst’s 20 h stream performance demonstrated its great stability. DFT analysis revealed an alteration in the electronic properties of nickel upon Ga incorporation, the d-band center of the Ga modified catalyst (Ga/Ni ratio of 0.3) shifted closer to the Fermi level, and a charge transfer from Ga to Ni atoms was observed. This research provides valuable insights into the development of Ga-modified catalysts and emphasizes their potential for efficient conversion of greenhouse gases into syngas.

High Entropy Induced Local Charge Enhancement Promotes Frank–Van der Merwe Growth for Dendrite‐Free Potassium Metal Batteries

AbstractPotassium metal batteries (PMBs) are promising for next‐generation energy storage. However, the high reactivity of the anode causes instability in the solid electrolyte interface (SEI), resulting in Volmer‐Weber (V‐W) type deposition. To achieve uniform Frank‐van der Merwe (F‐M) type deposition, high entropy alloy nanoparticles are designed (HEA NPs) with equimolar ratios of Mn, Fe, Co, Cu, and Ni to enhance the substrate‐K metal interface. HEA NPs enhance the K affinity of the N‐doped nanocarbon fiber substrate (N‐PCNF) and maximize ion and electron transport efficiency. The dendrite‐free horizontal growth of K metal confirmed through Operando X‐ray diffraction (XRD) and optical microscopy (OM). Consequently, the asymmetric cell exhibits ultra‐long cycling stability of 2350 hours at a high current density of 8 mA cm−2. The full cell composed of molten K diffusion into HEA NPs decorated N‐PCNF anode with perylene‐3,4,9,10‐tetracarboxylic dianhydride cathode (HEA‐N‐PCNF‐K||PTCDA) delivers an energy density of 331 W h kg−1 and remains stable over 2000 cycles. This study offers a promising pathway for innovative PMBs designs with broad application prospects.

Temperature dependence on γ/γ' partitioning behaviors of alloying elements and γ/γ' interfacial energy of a Mo-rich Ni based single crystal superalloy

Based on three-dimensional atom probe technique and Ardell method, the influences of temperature (850℃∼1150℃) on microstructure, compositions and solid solution strengths of γ and γ′ phases, γ/γ' partitioning behaviors of alloying elements and γ/γ' interfacial energy of a Mo-rich Ni based single crystal superalloy were investigated. After quenching from 1100℃, microstructure was basically similar as heat-treated state. However, after quenching from 1150℃, γ′ phase obviously re-dissolved, and γ channel obviously widened. Meanwhile, with increasing temperature, Co, Cr, Mo and Re contents in γ phase decreased, while Al and Ta contents in γ phase increased. With increasing temperature, Co, Cr and Re contents in γ′ phase slightly decreased, Mo content in γ′ phase significantly decreased, while Al and Ta contents in γ′ phase increased. Meanwhile, with increasing temperature, solid solution strength of γ phase decreased, while solid solution strength of γ′ phase increased. In addition, with increasing temperature, partitioning ratios of Co, Cr and Re elements decreased, partitioning ratios of Mo and Al elements increased, while partitioning ratio of Ta firstly decreased and then increased. Moreover, both γ/γ′ interfacial width and γ/γ′ interfacial energy decreased with increasing temperature.

Fine-tuning syngas composition using laser surface modified silver electrode for CO2 electroreduction

Electrochemical reduction of CO2 and H2O to synthesize gas (H2 and CO mixture) is of significant interest due to established industrial pathways to tune the H2 to CO composition to generate an array of valuable products including methanol, synthetic fuel, synthetic natural gas, and hydrogen. However, controlled H2:CO ratios are challenging on CO-active electrocatalysts like silver. We demonstrate that applying laser engineering to adjust the surface wetting state of a silver electrocatalyst with water contact angles θw ranging from 47° and 135°, H2:CO ratios can be tuned from 1 to 4 at modest potentials (−0.7 V versus RHE, RHE—reversible hydrogen electrode) with almost total unity Faradaic efficiency. Both hydrophilic (θw = 47°) and more hydrophobic (θw = 135°) samples showed an increasing H2:CO trend with rising potentials (0.7–1.2 V versus RHE) due to mass transport. Conversely, silver electrocatalyst with θw = 110° exhibited a constant H2:CO ratio of 4. This indicates catalyst wettability potentially affects *H and *HOCO intermediates’ adsorption, impacting H2:CO ratios. Our results show the feasibility of syngas composition control on silver catalysts via surface wettability, providing a simpler alternative to complex multicomponent electrocatalytic systems.

Colorimetric Oxygen Sensing by Analyzing Chromaticity Points for Polymer Cobalt Schiff Base in CIELAB

AbstractPolymer membranes of a copolymer ligand (L) coordinated to tetra‐coordinated N,N'‐ethylene bis(salicylideneiminato) cobalt(II) at the fifth coordinating site of the center cobalt(II), Co(II)S‐L, are prepared to measure colorimetrically the color changes in response to rapid reversible oxygen binding simultaneously with slow oxidation under moist conditions to yield Co(III)S‐L. The chromaticity point observed in CIELAB is the endpoint of the vector sum of the unit vectors for Co(II)S‐L, O2‐Co(II)S‐L, and Co(III)S‐L, scaled by their respective abundance ratios: (1 − m)(1 − n), m(1 − n), and n, where m is the ratio of O2‐Co(II)S‐L to the sum of Co(II)S‐L and O2‐Co(II)S‐L and n is the ratio of Co(III)S‐L to the total of the three cobalt complexes. The observed limited area in CIELAB as a stoichiometric Euclidean space is supported by the following two different reaction processes of the polymer membranes: an oxygen‐binding reaction under several different partial pressures of oxygen supplied to the membranes in a short period, during which oxidation of the cobalt(II) complexes is negligible, and an oxidation reaction over a long period at a constant partial pressure of oxygen. The chromaticity points in both processes progress linearly in three different two‐dimensional coordinates: a*b*, a*L*, and b*L*.

Microstructures and properties of a novel cemented carbide prepared using a Co–Ni–Cu multiprincipal element alloy as the binder

A Co–Ni–Cu multiprincipal element alloy (MPEA) powder was successfully synthesized through coprecipitation. Results of energy dispersive spectroscopy (EDS) and X-ray fluorescence spectroscopy (XRF) revealed nearly equal atomic ratios for Co, Ni, and Cu in the Co–Ni–Cu MPEA powder. Moreover, X-ray diffraction (XRD) confirmed a single-phase face-centered cubic (fcc) structure in the Co–Ni–Cu MPEA powder. To explore the differences in microstructure and mechanical properties, we compared a novel WC–2Co–2Ni–2Cu cemented carbide, utilizing the Co–Ni–Cu MPEA as a binder, with conventional WC–6Co and WC–3Co–3Ni cemented carbides prepared via liquid phase sintering. This comparison was conducted using scanning electron microscopy, XRD, and mechanical properties testing. Observations revealed that the surfaces of WC grains in WC–2Co–2Ni–2Cu and WC–6Co appeared smooth and flat, while those in WC–3Co–3Ni exhibited roughness with numerous terraces. In addition, the average grain size was 0.96, 1.14, and 1.22 μm in WC–2Co–2Ni–2Cu, WC–6Co, and WC–3Co–3Ni, respectively. Notably, the Co–Ni–Cu MPEA inhibited WC grain growth. WC–2Co–2Ni–2Cu (1388 HV30) exhibited hardness similar to that of WC–6Co (1406 HV30) but the highest fracture toughness (9.04 MPa∙m1/2), while WC–3Co–3Ni (1332 HV30) presented the lowest hardness. Bending strength values were recorded at 2406 MPa for WC–2Co–2Ni–2Cu, 2816 MPa for WC–6Co, and 2645 MPa for WC–3Co–3Ni, with WC–6Co exhibiting the highest bending strength. Considering their microstructures, physical properties, and mechanical properties comprehensively, the novel cemented carbides exhibited only slightly reduced bending strength compared to conventional counterparts. Thus, the Co–Ni–Cu MPEA binder demonstrates promising potential as a replacement for the conventional Co metal binder.

Preparation of Co-Ce@RM catalysts for catalytic ozonation of tetracycline.

In this work, a Co-Ce@RM ozone catalyst was developed using red mud (RM), a by-product of alumina production, as a support material, and its preparation process, catalytic efficiency, and tetracycline (TCN) degradation mechanism were investigated. A comprehensive assessment was carried out using the 3E (environmental, economic, and energy) model. The optimal production conditions for Co-Ce@RM were as follows: The doping ratio of Co and Ce was 1:3, the calcination temperature was 400°C, and the calcination time was 5h, achieving a maximum removal rate of 87.91% of TCN. The catalyst was characterized using different analytical techniques. Under the conditions of 0.4L/min ozone aeration rate, with 9% catalyst loading and solution pH9, the optimal removal rates and chemical oxygen demand by the Co-Ce catalytic ozonation at RM were 94.17% and 75.27%, respectively. Moreover, free radical quenching experiments showed that superoxide radicals (O2 -) and singlet oxygen (1O2) were the main active groups responsible for the degradation of TCN. When characterizing the water quality, it was assumed that TCN undergoes degradation pathways such as demethylation, dehydroxylation, double bond cleavage, and ring-opening reactions under the influence of various active substances. Finally, the 3E evaluation model was deployed to evaluate the Co-Ce@RM catalytic ozonation experiment of TCN wastewater. PRACTITIONER POINTS: The preparation of Co-Ce@RM provides new ideas for resource utilization of red mud. Catalytic ozonation by Co-Ce@RM can produce 1O2 active oxygen groups. The Co-Ce@RM catalyst can maintain a high catalytic activity after 20 cycles. The degradation pathway of the catalytic ozonation of tetracycline was fully analyzed. Catalytic ozone oxidation processes were evaluated by the "3E" (environmental, economic, and energy) model.

Exploring the potential of cobalt-based catalysts in the methane dry reforming for sustainable energy applications

Cobalt-based powder catalysts with different Co loadings were synthesized via wet impregnation using MgAl2O4 spinel as support. The catalytic properties of the solids were evaluated in the dry-reforming methane at different reaction temperatures and two CH4:CO2 ratios. The catalyst with higher cobalt content (13 %) presented superior performance due to increased Co0 species availability, confirmed by XPS analysis. Besides, this catalyst displayed remarkable resistance to carbon deposition at 550 °C and CH4:CO2 1: 1 ratio. In-situ DRIFT measurements demonstrated the formation and transformation of carbonate and hydrogen carbonate species during the DRM reaction, highlighting efficient CO2 and CH4 activation on the catalyst surface. Based on this data, a structured catalyst was deposited on top of the FeCrAlloy monolith, which was active, stable, selective for H2, and resistant against on/off cycles. Compared with the powder catalyst, the structured system displayed higher catalytic activity, possibly due to higher reducibility of metal species and improved heat transfer provided by the FeCrAlloy substrate. The results highlight the potential of Co-based structured catalysts for H2 or synthesis gas production processes.

Enhancing photocatalytic performance of rose-shaped Co/Ni bimetallic organic framework for reducing CO2 to CO under visible light

Co-MOF-74, composed of Co salt as the metal source and 2,5-dihydroxyterephthalic acid as the organic ligand, is widely used as a catalyst for the photocatalytic reduction of CO2 due to its open metal sites, high porosity, large specific surface area, and high CO2 adsorption capacity. However, its effectiveness in CO2 conversion is limited by weak electron transfer capabilities and a high rate of electron/hole pair recombination. To address these limitations, a bimetallic strategy was employed to significantly improve the catalytic performance of Co-MOF-74 for photocatalytic CO2 reduction. Stable bimetallic Co/Ni-MOF-74-x (x = 1, 2, 3) with controllable morphology and metal ratios were synthesized by adjusting the molar ratios of Co2+ and Ni2+ and combining them with 2,5-dihydroxyterephthalic acid. The introduction of Ni2+ led to a significant increase in the specific surface area, from 204.999 m2/g (Co/Ni-MOF-74) to 790.873 m2/g (Co/Ni-MOF-74-1). In addition, the band gap of bimetallic Co/Ni-MOF-74-1 was narrowed to 1.4 eV, which enhanced charge transfer. As a result, photocatalytic experiments demonstrated that the CO2 conversion efficiency of bimetallic Co/Ni-MOF-74-1 was significantly improved, reaching 4.539 mmol/g/h, compared to that of the monometallic Co-MOF-74. Finally, a synergistic photocatalytic mechanism involving ligand activation was proposed to explain the reaction process of the bimetallic Co/Ni-MOF-74 catalyst. Meanwhile, this study highlights that the bimetallic strategy is an effective approach to optimizing the performance of MOF catalysts for the photocatalytic reduction of CO2.

Elemental Zn modulation of interfacial structure and in situ construction of (FeCoNiCuZn)O high-entropy oxide/ZnO heterojunction for photocatalytic Rhodamine B dyes

In this study, inspired by the lattice distortion effect of HEOs, we adopt a non-equimolar strategy, fixing the molar ratios of Fe, Ni, Cu, and Co while varying the molar ratio x of Zn/(FeNiCuCo) (x=0.25, 0.5, 1.0, 1.5 and 2.0) to synthesize the HEO-x compounds. With an increase in the Zn content, lattice distortion occurred in the spinel phase of the (FeNiCuZnCo)O HEO, resulting in the gradual precipitation of ZnO nanocrystals. The (220) crystal plane of the spinel phase closely connects with the (100), (002), and (101) crystal planes of the ZnO phase, forming nano-heterojunctions. The HEO-1.5 prepared by controlling the Zn element proportion exhibits a high photocatalytic degradation rate of Rhodamine B (RhB) of up to 99.45 %. The kinetic degradation rate of HEO-1.5 is 17 times higher than that of HEO-0.25, attributed to the nano-heterojunctions formed by the spinel phase and ZnO phase, facilitating effective separation of photogenerated electron-hole pairs, promoting the generation of active free radicals, and rapidly degrading RhB.

Impact of B2O3/Co3O4 substitution on structure, physical, optical characteristics and photon attenuation capacity of borosilicate glasses

The impact of substitution of B2O3/Co3O4 in borosilicate glasses on their optical, structural, and physical characteristics as well as their ability to attenuate γ-rays was examined. Using the traditional melt quenching process, glass samples with the chemical formula (45-X)B2O3+15SiO2+ 20BaF2+20Na2O + XCo3O4, where X equals 0.0, 0.5, 1.0, 1.5, and 2.0 mol%. The prepared samples were coded as Co-0.0 - Co-2.0. XRD measurements revealed the non-crystalline character of the Co-X samples. The molar volume (Vm) decreased from 31.19 cm3/mol to 31.08 cm3/mol, although the density (ρ) increased from 2.81 g/cm3 to 2.94 g/cm3. When comparing Co-0.0 and Co-2.0, the direct optical band gap (EgDirect) values reduced from 4.32 eV to 3.77 eV, while the indirect optical band gap (EgIndirect) decreased from 3.93 eV to 3.44 eV. The Co-X glasses' Urbach's energy (EU) ranged from 0.297 eV to 0.248 eV. As the ratio of Co2+ ions rose, the optical dielectric constants of Co-X glasses, ε1 (actual part) and ε2 (imaginary portion) were improved. The linear (μ) and mass (μm) attenuation coefficients and effective atomic number (Zef) were followed the order: Co-2.0 > Co-1.5 > Co-1.0 > Co-0.5 > Co-0.0. The created Co-2.0 glass, which has the maximum amount of cobalt (III) oxide, has the lowest mean free path (MFP) and half/tenth value layers (H/TVL). The examined Co-X glasses can be employed for optical and γ-ray shielding purposes, as confirmed by the results.

Artificial neural network based forecasting of diesel engine performance and emissions utilizing waste cooking biodiesel

Ecological and environmental problems resulting from fossil fuels are due to the harmful emissions released into the atmosphere. The rising interest in searching for alternative fuels like biodiesel is growing to solve these problems. Waste cooking oil (WCO) is transformed into methyl ester and combined with biodiesel in percentages of 25, 50, 75, and 100%. Research is done on the impacts of methyl ester blends on engine performance and emissions. Compared to diesel, the methyl ester combination showed 25% lower brake power and 24% loss in thermal efficiency at maximum load and 1500 rpm. However, diesel fuel showed 23% lower specific fuel consumption increase than biodiesel. Compared to diesel, methyl ester exhibits 15% lower air-fuel ratio and 4% volumetric efficiency. Biodiesel lowers CO, HC, and smoke concentrations by 12, 44, and 48%, respectively, compared to diesel. Biodiesel emits 23% higher NOx at 1500 rpm and 100% engine load. To predict the emissions and performance of different percentages of biodiesel at engine speed variation, an artificial neural network (ANN) model is presented. ANN modeling minimizes labor, time, and finances and uses nonlinear data. Predictions were produced about the brake output power, specific fuel consumption, thermal efficiency, air-fuel ratio, volumetric efficiency, and emissions of smoke, CO, HC, and NOx as a function of engine speed and blend ratio. All correlation coefficients (r) over 0.99 and R2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R^{2}$$\\end{document} values were beyond 0.98 for all variables. There were low values of MSE, MAPE, and MSLE with significant predictive ability. WCO’s biodiesel is a viable diesel engine replacement fuel.

Functional variations in efficiency of PSII during leaf ontogeny in the tropical plant Saraca asoca

Leaf ontogeny of tropical evergreen tree species lasts several months with changes in size, shape, colouration and internal tissue distribution of leaves. Leaf initiation in Saraca asoca generally occurs once in a year during February–April, followed by very limited leafing thereafter. We measured the rate of photosynthesis, chlorophyll a fluorescence, energy quenching and PSII functions during the leaf ontogeny process. Observations were taken up to 35 days after opening of lamina (DAOL). Significant increase in the synthesis and accumulation of photosynthetic pigments but negative net photosynthesis was noticed during initial days of the ontogeny. The leaf moved from heterotrophy to autotrophy with gradual improvement of PSII functions. The ratio of intercellular CO2 (Ci) and ambient CO2 (Ca) showed significant change at ≥11 DAOL. Increase in the age of the leaf (between 5 and 28 DAOL) caused decrease in O-J rise and corresponding increase in J-I and I-P rise as well as of fluorescence maximum (FM) of the OJIP curve. The improvement of the electron transport components of the donor side of PSII was seen with increase in the functional oxygen evolving complex. The functional improvements of the donor and acceptor side of PSII during leaf ontogeny are discussed.

Responses of greenhouse gas emissions to increased precipitation events in different ecosystems: A meta-analysis

Changes in precipitation patterns induced by climate change exacerbate the phenomenon by stimulating carbon (C) and nitrogen (N) processes in terrestrial ecosystems, leading to increased emissions of soil greenhouse gases (GHGs). However, the response of soil GHG fluxes across various global ecosystems under conditions of increased precipitation (IP) and extreme precipitation (EP) remains unclear. This study conducted a meta-analysis to examine the effects of IP and EP on soil GHG fluxes, synthesizing data from 49 published studies worldwide, and explored potential influencing factors. The results indicated that (1) IP significantly elevated CO2 emissions by 10.2 % and N2O emissions by 61.7 %, and did not impact CH4 emissions. EP treatment significantly increased N2O emissions by 61.8 %, CO2 emissions by 13.3 %, and CH4 emissions by 3.2 %. (2) Under IP treatment, significant differences in soil GHGs among various ecosystems were observed (P < 0.01). Among the three analyzed ecosystems (grassland, forest, and farmland), the response ratios of CO2 (30.4 %), N2O (61.8 %), and soil respiration (37.5 %, excluding plant respiration) were highest in the forest ecosystem and lowest in the grassland. (3) The response of CO2 flux to precipitation was most affected by soil dissolved organic C (P < 0.001) and microbial biomass C (P < 0.001). The key factor affecting the change in N2O flux was NH4+-N (P < 0.001). These findings provide a new perspective for understanding the effects of IP on soil C and N cycles in the context of global climate change.

PSIX-22 Maternal methane, carbon dioxide, and oxygen flux compared with progeny gas flux

Abstract Red Angus heifers [n = 19; body weight (BW) = 370 ± 8.1 kg) and their paired offspring (BW = 283 ± 4.2 kg; 18 heifers, 1 steer) were used to compare the respiration gas parameters between dams and their progeny over 2 calving cycles (8 pairs in the 1st cycle, 11 in the 2nd). The methane (CH4), carbon dioxide (CO2) emissions and oxygen (O2) consumption of the dams were measured at 14 mo of age over a 70-d period using an automated head-chamber system (AHCS) that measured the flux of these 3 gases. Dams grazed native mixed-grass prairie and were offered a daily supplement of alfalfa (Medicago sativa L.) pellets (1.0 kg) via the AHCS. Dams were artificially inseminated using sexed semen (female) from a single Black Angus sire. The gas fluxes of the progeny were measured, beginning at 11 mo of age, over a 70-d period. Like the dams, during their measurement period, the progeny grazed native mixed-grass prairie and were offered a daily supplement (1.0 kg) of alfalfa pellets via the AHCS. Pearson correlations were developed between the 70-d means of daily CH4 and CO2 emissions, O2 consumption, CH4:CO2 ratio, respiratory quotient (RQ), and heat of production estimates for the dams and their progeny by regressing maternal parameters on the parameters of the progeny, using beginning dam and progeny BW as covariates, and year as an indicator variable. A dam’s CH4 emission was very strongly correlated with that of their offspring (ρ = 0.86). The CO2 emission and O2 consumption of the dams were both also very strongly (ρ = 0.92 and ρ = 0.97, respectively) correlated, with that of their progeny. The heat production and CH4:CO2 ratio of the dams were very strongly (ρ = 0.96) and fairly (ρ = 0.50) correlated, respectively, with that of their progeny. Lastly, the RQ of the dam was also very strongly correlated (ρ = 0.87) with the RQ of the progeny. These results indicate that CH4 and CO2 emissions, O2 consumption, CH4:CO2 ratio, and heat of production of the dam are fairly to very strongly correlated to the gas flux parameters of their progeny. Hence, even with this small dataset, there is evidence that beef cattle traits related to greenhouse gas emissions are somewhat heritable and could potentially be selected in breeding animals to decrease greenhouse gas emission intensity.

Growth behavior of anisotropic monometallic MOFs derivatives with the high absorbing and thermal properties

The growth behavior and morphological characteristics of metal-organic frameworks (MOFs) should be considered as important factors in understanding their structure. Therefore, MOFs with atypical shapes, heterogeneous structures or abnormal properties that grow anisotropic can serve as components and templates for further directed assembly or conversion into MOF derivatives with excellent performance in electromagnetic wave absorption. Cobalt (Co) and nickel (Ni) metals have good magnetic properties and are common materials for the preparation of monometallic MOF-derived. In this study, various MOF materials with anisotropic properties, such as rod-like, flower-like, and braided, were prepared by adjusting the molar ratio of Co and Ni solvent to the organic ligand. Due to the rich inter-facial polarization and strong magnetic coupling network of the magnetic composites, Ni-MOF-b (Ni-MOF with braided shape) was prepared for the first time when the molar ratio of nickel nitrate to linker was 1:1.2. The Ni-C-b was obtained after pyrolysis of Ni-MOF-b, the minimum reflection loss of Ni-C-b was –50.7 dB at 4.0 mm. In addition, the thermal conductivity of the film prepared with Ni-C-b as filler is 2.2 W/mK. The film with integrated good heat dissipation and wave absorbing properties provides a research idea for the design of multifunctional integrated film.

Effects of H2S content on the corrosion behavior of gas storage reservoir injection and production pipeline steel in CO2-H2S environment

The effects of H2S content on the corrosion behavior of gas storage reservoir injection and extraction pipeline steel in a CO2-H2S environment were investigated by surface characterization and ultrasonic thickness measurement. The results show that the corrosion products of gas injection and extraction pipelines under real conditions are more complex. In the CO2-H2S environment, with the increase of H2S content, the corrosion rate of gas storage reservoir gas injection and extraction pipeline steel firstly increases and then decreases. At a partial pressure ratio of CO2 to H2S of 550, corrosion resulted mainly in the formation of FeCO3, FeS2, and Fe3O4, with limited generation of stabilizing protective films. This led to severe localized corrosion, mainly driven by CO2. In contrast, when the CO2 to H2S partial pressure ratio was reduced to 5.2, the corrosion mainly produced Fe7S8, FeS2, and BaSO4, which promoted the formation of a more stable protective film on the inner wall of the tube, while the presence of gums reduced the severity of the localized corrosion and shifted the corrosion control to H2S.

Zn-substituted Co3O4 crystal anchored on porous carbon nanofibers for high performance supercapacitors

Metal-organic frameworks (MOFs) are a promising class of electrode materials for supercapacitors. In this work, MOF-derived transition metal oxide/carbon nanofiber composites (ZnCoO/C) are synthesized through a freeze-drying method followed by a carbonization process. The crystal structure of the ZnCoO/C product is regulated by changing the ratio of Co to Zn, which in turn influences its electrode properties. The electrochemical tests reveal that the ZnCoO/C-2 electrode demonstrates an impressive specific capacitance of 356.3 F g-1 at 1 A g-1 and maintains a capacitance retention exceeding 77 % after 10,000 cycles, which exhibits a good cycling stability. It is found that appropriate Zn substitution can diminish the crystallinity of the material, augment the active sites, and enhance the specific capacitance of the electrode material. Considering the heteroatom substitution tends to introduce vacancy defects in the crystals, this work theoretically explores the effect of oxygen vacancies on the electrode materials. As the oxygen vacancy concentration increases, the band gap and the adsorption energy of the models decrease; conversely, the formation energy of the models shows an increasing tendency. This indicates that an increase in oxygen vacancies can enhance the electrical conductivity of electrode materials and facilitate their kinetic process but destroy the stability of crystal. This research explores the interplay between the microstructure and the electrochemical performance of electrode materials, providing a foundational reference for the design of structurally optimized high-performance electrodes and further elucidating the energy storage mechanisms in supercapacitors.