Institutional Repository of GuangZhou Institute of Energy Conversion, CAS
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High-temperature resistant BaO-Y<sub>2</sub>O<sub>3</sub> catalysts with different morphologies for NO decomposition and mechanism study
No full textThe high-temperature reaction is a common phenomenon in combustion society, and its catalytic response remain a tremendous challenge hampered by the activity and resistance of the catalyst to high temperatures exceeding 1000 degrees C Three distinct forms of BaO-Y2O3 catalysts-nanosphere, nanorod, and rod-were created using a hydrothermal method and high-temperature annealing to enable direct decomposition of NO. To gather reaction-relevant structural and property information for BaO-Y2O3, we combined reactor activity measurements, chemisorption and DFT studies to elucidate NO high-temperature decomposition process and pinpoint the critical role of oxygen vacancy. We have systematically clarified the increasing favorability of NO decomposition on the nano-catalysts (nanospheres and nanorods) at high temperatures is through stable lattice structure, large specific surface areas, high porosity, and active Ba-O-Y bond. Due to the attraction of electrons gathering in vacancies to NO molecules, oxygen vacancies created in situ at high temperatures, as validated by O-2-TPD and density functional theory (DFT) calculations, are advantageous for NO adsorption and decomposition. Moreover, N-2 formation pathway over Ba-Y2O3(111) structure is revealed by DFT calculations that NO molecules are apt to be caught by active sites, the region of Ba-O-Y, resulting in the production of N2O2 intermediate and its subsequent bond breaking to N2O as well as N-2. In situ DRIFTS experiment further confirms the reaction mechanism via the detected adsorbed species, and clarify the significance of NO2- to O-2 formation. In a nutshell, the synthetic combustion catalysts are effective in high-temperature environments that contribute to de-NOx combustion, and the insights into the adsorption configurations of reactant and intermediates unlock fundamental understanding for emissions gas chemistry
High-temperature resistant BaO-Y<sub>2</sub>O<sub>3</sub> catalysts with different morphologies for NO decomposition and mechanism study
No full textThe high-temperature reaction is a common phenomenon in combustion society, and its catalytic response remain a tremendous challenge hampered by the activity and resistance of the catalyst to high temperatures exceeding 1000 degrees C Three distinct forms of BaO-Y2O3 catalysts-nanosphere, nanorod, and rod-were created using a hydrothermal method and high-temperature annealing to enable direct decomposition of NO. To gather reaction-relevant structural and property information for BaO-Y2O3, we combined reactor activity measurements, chemisorption and DFT studies to elucidate NO high-temperature decomposition process and pinpoint the critical role of oxygen vacancy. We have systematically clarified the increasing favorability of NO decomposition on the nano-catalysts (nanospheres and nanorods) at high temperatures is through stable lattice structure, large specific surface areas, high porosity, and active Ba-O-Y bond. Due to the attraction of electrons gathering in vacancies to NO molecules, oxygen vacancies created in situ at high temperatures, as validated by O-2-TPD and density functional theory (DFT) calculations, are advantageous for NO adsorption and decomposition. Moreover, N-2 formation pathway over Ba-Y2O3(111) structure is revealed by DFT calculations that NO molecules are apt to be caught by active sites, the region of Ba-O-Y, resulting in the production of N2O2 intermediate and its subsequent bond breaking to N2O as well as N-2. In situ DRIFTS experiment further confirms the reaction mechanism via the detected adsorbed species, and clarify the significance of NO2- to O-2 formation. In a nutshell, the synthetic combustion catalysts are effective in high-temperature environments that contribute to de-NOx combustion, and the insights into the adsorption configurations of reactant and intermediates unlock fundamental understanding for emissions gas chemistry
Kinetics analysis of cellulose chemical-looping gasification using Ca-Fe oxygen carrier
No full textCa-Fe oxygen carrier (OC) is an effective material with high selectivity on H2 and CO to aid to the gasification of solid fuel materials such as organic solid waste or biomass in chemical-looping gasification (CLG). However, the reaction mechanism of raw materials with high volatiles such as cellulose remains unclear. Kinetics analysis is considered as the efficient method to investigate the reaction mode and mechanism. In this study, isothermal method was conducted and the tristate intermedia products were used as substrates to reveal the kinetics characteristic of cellulose conversion process in CLG. The results demonstrated that the reduction process of Ca-Fe OC could be divided into three stages, and the activation energies were 40.40 kJ/mol, 91.28 kJ/mol and 165.33 kJ/mol, respectively; this indicates that the lattice oxygen could be transferred easily in the first stage, but much more difficult in the later two stages. The weak oxidizing molecules such as CO2 could re-oxide the reduced OC quickly and the activation energy was 27.83 kJ/mol. The mechanism model on kinetic of tar cracking was similar to the reaction between H2 and OC, and the activation energy was 82.27 kJ/mol. The decomposition of char was recognized as the stochastic nuclear shrinkage process with an activation energy of 52.22 kJ/mol
Deciphering stakeholder strategies in electric vehicle battery recycling: Insights from a tripartite evolutionary game and system dynamics
No full textGiven that the global fleet of electric vehicles is expanding rapidly, leading to a surge in demand for power batteries, the significance of battery recycling has come sharply into focus. In this paper, we develop a tripartite evolutionary game model coupled with a system dynamics simulation approach to analyze the behavioral mechanisms of stakeholders in electric vehicle battery recycling and to identify the key factors influencing their strategic transformations. The model involves three key stakeholders: local governments, battery cathode manufacturers, and battery pack manufacturers. Through profit analysis and the formulation of a replicator dynamics system, coupled with the application of Vensim for system dynamics modeling, we analyze the effects of ten crucial exogenous variables on stakeholder strategies. Our research highlights the crucial role of government actions, such as subsidies and penalties, in directing corporate strategies. Notably, excessively high subsidies (over 2.1 million Chinese Yuan) lead to dependency among cathode manufacturers. Market factors, including increased battery sales and the preference for low-carbon procurement by electric vehicle manufacturers, are shown to significantly motivate cathode manufacturers to adopt recycling strategies and encourage pack manufacturers to develop recyclable designs. Additionally, the introduction of EU battery regulations and the integration of cathode manufacturers into carbon trading schemes have been identified as positive catalysts for strategic shifts, especially for cathode manufacturers, while exerting minimal influence on pack manufacturers. This paper elucidates the intricate interaction of the behavioral patterns and key motivators affecting stakeholder strategies in electric vehicle battery recycling
A sustainable bio-circular way for biorefinery of rice straw into bioproducts based on energy-efficient pretreatment
No full textLignocellulosic biorefinery faces challenges associated with high energy input during pretreatment and high enzyme cost for enzymatic hydrolysis of cellulose, as well as the intricate valorization of lignin and hemicellulose. This study applied KOH-urea pretreatment to obtain maximum lignin removal of 68.93 % from rice straw at 80 degrees C for 60 min. The pretreatment consumed only 10.49 % of the total energy input. Five-time dilution of neutral black liquor can optimally stimulate the plant growth. Enzymatic conversion of KOH-urea-treated rice straw attained 92.02 % at 20 % solid concentration with 10 FPU cellulase/g substrate. The ethanol concentration achieved 37.02 g/L at a yield of 75.89 %. The solid residue after fermentation contained 42.40 % dietary fiber and 16.70 % protein, which is suitable as animal feed. This study developed a simple bio-circular way to concurrently produce liquid fertilizer, bioethanol, and animal feed from rice straw
Hyper-Cross-Linked Resin Modified by a Micropore Polymer for Gas Adsorption and Separation
No full textPolymerization confined to the pore was first adapted for the nanoscale structure adjustment of adsorption resin. The self-cross-linked polymer (P-1) formed in the pore of hyper-cross-linked resin (HR) by the Friedel-Crafts reaction of p-dichloroxylene (p-DCX), occupying the macropore of the HR resin and bringing about an external micropore. Compared with the raw HR resin, the volume of the micropore of HR@P-1 in 0.4 < D < 1 nm increased but the volume of the macropore has obviously decreased. After the loading of P-1 in the nanopore of HR, HR@P-1 has better gas adsorption performance. At 298 and 100 KPa, the adsorption capacity of CO2 is almost 30% higher than that of HR, reaching 35.7 cm(3)/g, due to the increase in the smaller micropore volume. Moreover, HR@P-1 has also been found to be the first C2H6-selective adsorption resin. The uptake of C2H6 is up to 56 cm(3)/g, and the IAST selectivity of C2H6/CH4 reaches 15.3. HR@P-1 can also separate syngas efficiently at ambient temperature and be regenerated by simple vacuum operation
Iron-Cobalt Nanoparticles Embedded in B,N-Doped Chitosan-Derived Porous Carbon Aerogel for Overall Water Splitting
No full textGiven their intriguing properties, porous carbons have surfaced as promising electrocatalysts for various energy conversion reactions. This study presents a unique approach where iron-cobalt (FeCo) is confined in a boron, nitrogen-doped chitosan-derived porous carbon aerogel (BNPC-FeCo) to serve as an electrocatalyst for the hydrogen evolution and oxygen evolution reactions (HER and OER). The BNPC-FeCo-900 electrocatalyst demonstrates excellent catalyst activity, with very low overpotentials of 186 and 320 mV at 10 mA cm(-2), low Tafel slopes of 82 and 55 mV dec(-1), and low charge transfer resistance of 2.68 and 9.25 Omega for HER and OER, respectively. Density functional theory (DFT) calculations further reveal that the cooperation between the boron, nitrogen codoped porous carbon, and the FeCo nanoparticles reduces intermediates' energy barriers, significantly enhancing the HER and OER performance. In conclusion, this work offers significant and informative perspectives into the potential of porous carbon materials as dual-purpose electrocatalysts for water splitting
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