Institutional Repository of GuangZhou Institute of Energy Conversion, CAS
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Unraveling the atomic interdiffusion mechanism of NiFe<sub>2</sub>O<sub>4</sub> oxygen carriers during chemical looping CO<sub>2</sub> conversion
No full textBy employing metal oxides as oxygen carriers, chemical looping demonstrates its effectiveness in transferring oxygen between reduction and oxidation environments to partially oxidize fuels into syngas and convert CO2 into CO. Generally, NiFe2O4 oxygen carriers have demonstrated remarkable efficiency in chemical looping CO2 conversion. Nevertheless, the intricate process of atomic migration and evolution within the internal structure of bimetallic oxygen carriers during continuous high-temperature redox cycling remains unclear. Consequently, the lack of a fundamental understanding of the complex ionic migration and oxygen transfer associated with energy conversion processes hampers the design of high-performance oxygen carriers. Thus, in this study, we employed in situ characterization techniques and theoretical calculations to investigate the ion migration behavior and structural evolution in the bulk of NiFe2O4 oxygen carriers during H-2 reduction and CO2/lab air oxidation cycles. We discovered that during the H-2 reduction step, lattice oxygen rapidly migrates to vacancy layers to replenish consumed active oxygen species, while Ni leaches from the material and migrates to the surface. During the CO2 splitting step, Ni migrates toward the core of the bimetallic oxygen carrier, forming Fe-Ni alloys. During the air oxidation step, Fe-Ni migrates outward, creating a hollow structure owing to the Kirkendall effect triggered by the swift transfer of lattice oxygen. The metal atom migration paths depend on the oxygen transfer rates. These discoveries highlight the significance of regulating the release-recovery rate of lattice oxygen to uphold the structures and reactivity of oxygen carriers. This work offers a comprehensive understanding of the oxidation/reduction-driven atomic interdiffusion behavior of bimetallic oxygen carriers
Study of high conductivity electrode for superior performance lithium-ion batteries based on low tortuosity corn straw biochar/VS4 with multichannel structure
No full textIt is an effective measure to achieve the application agricultural waste and the development of sustainable energy by effectively utilizing the corn straw with natural multichannel structure in electrochemical energy storage devices. Corn straw biochar as a sustainable and environmentally friendly form of clean energy, serves as a carbon-based material in electrode of lithium-ion batteries. The natural multi-channels and sieve tube structure is the foundation for the electrode with low tortuosity. Within the traditional carbon materials, these characteristics are not commonly presented. In this study, a strategy is proposed to boost the performance of the electrode by devising and modifying its structure. The multichannel and porous structure within the electrodes is achieved by leveraging the natural structure of corn straw. This unique structure can bring low tortuosity in the electrode, thereby facilitating the construction of the direct ions transfer channels and continuous electrons pathways. Moreover, the inherent nitrogenous feature of biochar result in enhanced surface polarity, enabling the electrode material to trap the polar polysulfides efficiently. Additionally, the multichannel and porous structure of elec-trode also bring sufficient space to accommodate volume expansion, thereby improving the stability of electrode. Therefore, this work points an effective approach to harnessing the potential of corn straw and also constructing an electrode with a multichannel and porous structure and low tortuosity, ultimately enhancing the electro-chemical performance for lithium batteries
Biocompatible organosolv fractionation via a novel alkaline lignin-first strategy towards lignocellulose valorization
No full textSimultaneous valorization of both carbohydrate and lignin fractions in lignocellulose remains a great challenge. Herein, a novel lignin -first strategy using triethylene glycol (TEG) under alkaline conditions for effective biomass fractionation producing highly digestible carbohydrates and reactive lignin was developed. Delignification was over 80% and fermentable sugar yields were close to 90% after pretreatment at 90 celcius. The biocompatibility of TEG allowed direct enzymatic hydrolysis of the solid residue without washing, thus minimizing wastewater generation. Moreover, the obtained lignin (TEGL) had an uncondensed structure with well-preserved beta-O-4 linkage, leading to near -equal aromatic monomer yields compared to cellulolytic enzyme lignin after catalyticfree pyrolysis, demonstrating high valorization potential. Overall, the proposed TEG solvent system is promising for a green and sustainable biorefinery process to achieve the complete utilization of lignocellulose
Stable Support Program of Colleges and Universities in Shenzhen, China[20200813153536001]
No full textBioaugmented ensiling of sweet sorghum with<i> Pichia</i><i> anomala</i> and cellulase and improved enzymatic hydrolysis of silage via ball milling
No full textSweet sorghum, as a seasonal energy crop, is rich in cellulose and hemicellulose that can be converted into biofuels. This work aims at investigating the effects of synergistic regulation of Pichia anomala and cellulase on ensiling quality and microbial community of sweet sorghum silages as a storage and pretreatment method. Furthermore, the combined pretreatment effects of ensiling and ball milling on sweet sorghum were evaluated by microstructure change and enzymatic hydrolysis. Based on membership function analysis, the combination of P. anomala and cellulase (PA + CE) significantly improved the silage quality by preserving organic components and promoting fermentation characteristics. The bioaugmented ensiling with PA + CE restructured the bacterial community by facilitating Lactobacillus and inhibiting undesired microorganisms by killer activity of P. anomala. The combined bioaugmented ensiling pretreatment with ball milling significantly increased the enzymatic hydrolysis efficiency (EHE) to 71%, accompanied by the increased specific surface area and decreased pore size/ crystallinity of sweet sorghum. Moreover, the EHE after combined pretreatment was increased by 1.37 times compared with raw material. Hence, the combined pretreatment was demonstrated as a novel strategy to effectively enhance enzymatic hydrolysis of sweet sorghum
Direct Hydrogenation of Furfural to 2-Methyltetrahydrofuran over an Efficient Cu-Pd/HY Bimetallic Catalyst
No full textThe direct one-pot conversion of furfural to 2-methyltetrahydrofuran (2-MTHF) was investigated in liquid phases using H-2 as a hydrogen source over a bimetallic Cu-Pd/HY catalyst. This catalyst showed excellent catalytic reactivity toward the formation of 2-MTHF with a yield of 83.1% under optimized reaction conditions. By adjusting the Cu/Pd ratio in the catalyst, the desired product could be obtained selectively. This was due to (1) selective catalysis of Cu toward C=O bonds in furfural, (2) excellent hydrogenation ability of Pd, and (3) the synergistic effects between Cu, Pd, and the acidic sites of the support HY. The influences of other parameters on conversion and selectivity were also investigated. Mechanism studies revealed that reactions mainly perform through the hydrogenation of furfural to furfuryl alcohol and then hydrodeoxygenation to 2-methylfuran followed by furan ring hydrogenation to 2-MTHF. Finally, after five recycling runs, this catalyst still displayed high catalytic behavior and stability, which provided a certain foundation for future research of furfural catalytic hydrogenation to 2-MTHF
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