Institutional Repository of GuangZhou Institute of Energy Conversion, CAS
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Funder Grant Number Young Talent Support Project of Guangzhou Association for Science and Technology[QT-2023-042]
No full textPreparation of carbon materials by vapor deposition with Fe3+-Modified nickel foam from biomass pyrolysis gas
No full textBiomass carbon materials have attracted attention in various fields due to their excellent properties. In this study, CH4 derived from biomass pyrolysis was utilized as a carbon source gas to synthesize carbon materials by chemical vapor deposition (CVD) in a two-stage reactor with purification system, with Fe3+-loaded nickel foam as the substrate under an argon atmosphere, using a self-designed experimental platform. The reaction process was optimized by examining the effects of the catalyst type, reaction temperature, reaction time, and gas flow rate on the structure and morphology of the carbon materials. The optimal preparation condition was to use FeCl3 ethanol solution as catalyst, with CH4 flow rate of 50 ml/min at 1000 degrees C for 25 min. The high quality carbon materials with uniform diameters (250-500 nm) were obtained on nickel foam substrate. The carbon materials obtained under optimal conditions were characterized and analyzed to investigate their excellent properties. Surface morphology and structure of as-formed carbon materials were characterized by SEM. The analysis of the XRD spectra and the Raman spectroscopy showed that the graphite diffraction peak (002) at 26.6 degrees, the calculated intensity ratios for ID/IG and I2D/IG were 0.257 and 0.545, respectively, indicated high degree of graphitization and purity of the carbon materials. Furthermore, the growth mechanism of carbon materials on the nickel foam substrate was discussed
Biomaterials Based on Lignocellulose
No full textWith the continuous depletion of fossil energy and the continuous destruction of the ecological environment, developing environmentally friendly renewable electrochemical energy storage devices and biomedical materials is particularly urgent. As an important renewable resource, lignocellulosic biomass has the advantages of low cost, easy accessibility, environmental friendliness, and rich pore structure, and it has a wide range of application prospects as a renewable, biodegradable, and biocompatible substrate for excellent modified materials. The treatment of biomass materials has been from the traditional methods (including combustion, feed, fertilizer and matrix processing), and gradually towards energy, ecology, material modification, and the preparation of new bio-based functional and smart material products, such as: high-performance energy storage devices and biomedical equipment. In short, the development of new matrix and functional materials with biomass as the main raw material is the development trend. In this study, the latest research progress in preparing biomass-derived materials for high-performance energy storage devices and biomedical fields is summarized and overlooked, and the problems and challenges are also pointed ou
Energy Recovery from Natural Gas Hydrate and Shallow Gas Reservoirs: Exploring the Impact of Interlayer Gas Cross-Flow Behaviors
No full textThe coproduction of natural gas hydrate (NGH) and shallow gas (SG) represents a promising pathway toward the commercialization of marine hydrate resources. However, there is still a gap in exploring the impact of interlayer gas cross-flow behaviors on the energy recovery from NGH-SG reservoirs and coproduction characteristics with different reservoir properties. In order to address the gap, we conducted numerical simulations to study the production characteristics and interlayer gas cross-flow behaviors based on an NGH-SG reservoir model. The results demonstrate that reservoir properties affect both gas production and interlayer gas cross-flow. Interlayer gas cross-flow during the production process reduces production efficiency. The increase in permeability of shallow gas layer (SGL) is more favorable to improve the gas yield of coproduction compared with the increase in permeability of hydrate-bearing layer (HBL) and thickness of interlayer. Higher HBL permeability improves the gas cross-flow, while increased SGL permeability accelerates gas cross-flow during the early stages of production. Nevertheless, the increase in interlayer thickness mitigates interlayer gas cross-flow. The low-pressure zone of the HBL under the depressurization effect of the wellbore during coproduction is more extensive than that of the SGL, leading to the formation of a large interlayer pressure difference between the two layers. The pressure difference serves as a decisive factor in determining the occurrence of gas cross-flow, in addition to gas permeability, which significantly influences cross-flow velocity. To assess the efficiency of gas production and energy loss during coproduction of NGH-SG reservoirs, we have established an evaluation panel based on the gas-water ratio and yield-loss ratio. Combined energy recovery efficiency and economic efficiency, high SGL permeability is more favorable for coproduction. The findings of this study significantly enhance our understanding of interlayer gas cross-flow behaviors during the development of multilayer reservoirs and provide valuable guidance for the efficient coproduction of NGH-SG reservoirs
Exploring Porous Flow Behavior of the Decomposed Gas from CH<sub>4</sub> Hydrate in Clayey Sediments by Molecular Dynamics Simulation
No full textA fundamental understanding of the fluid flow mechanism during CH4 hydrate dissociation in nanoscale clayey sediments from the molecular perspective can provide invaluable information for macroscale natural gas hydrate (NGH) exploration. In this work, the fluid flow behaviors of the decomposed gas from CH4 hydrate within clayey nanopores under different temperature conditions are revealed by molecular dynamics (MD) simulation. The simulation results indicate that the key influencing factors of gas-water flow in nanoscale clayey sediments include the diffusion and the random migration of gas molecules. The influencing mechanisms of fluid flow in nanopores are closely related with the temperature conditions. Under a low temperature condition, the gas diffusion process is impeded by the secondary hydrate formation, leading to the decline in gas transport velocity within nanopores. However, it is still noteworthy that the gas-water fluid flow channels are not completely blocked by the occurrence of secondary hydrate. Under a high temperature condition, the significant phenomenon of water migration during gas flow is observed, which can be ascribed to the gas-liquid entrainment effect in nanopores of the clayey sediment. These results may provide valuable implications and fundamental evidence for improving gas production efficiency in future field tests of NGH exploitation in marine sediments
Improving light harvesting and charge carrier separation enabling enhanced photoelectrochemical hydrogen production by Sb<sub>2</sub>S<sub>3</sub>-decorated TiO<sub>2</sub> nanotube arrays on porous Ti-photoanodes
No full textThe Ag + ions doped TiO2 nanotube arrays fabricated on Ti mesh through an electrochemical anodization process, and n/n heterostructure formed by coating the TiO2 nanotube array photoanode with an n-type stibnite (Sb2S3) layer improve photoelectrochemical water splitting reaction by enhancing light harvesting and charge carrier separation. Sb2S3 is chosen because of its suitable band gap position and strong visible light response. The Ag + ion incorporated TiO2 nanotube array coated with Sb2S3 exhibits a photocurrent density of 6.5 mA cm- 2 vs. RHE, whereas bare TiO2 nanotube array coated with Sb2S3 and pristine TiO2 nanotube array exhibit photocurrent densities of 3.6 and 0.27 mA cm- 2, respectively, under the same conditions, which is nearly 1.8 and 24 times greater than the TiO2 nanotube array coated with Sb2S3 and pristine TiO2 nanotube array photoanodes. The applied bias photon-to-current efficiency of Ag + ion incorporated TiO2 nanotube array coated with Sb2S3 is 3.6% and the improved Photoelectrochemical performance of Ag + ion doped TiO2 nanotube array coated with Sb2S3 is attributable to higher conductivity of TiO2 nanotube array caused by increased oxygen vacancies and broad optical activity of Sb2S3. The 1-dimensional TiO2 nanotube array device structure in the Ti mesh improves charge separation and light harvesting while reducing photogenerated charge carrier recombination and the potential of this novel device structure for advanced energy conversion applications is highlighted in this study
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