Dissolved hydrogen is harmful to mechanical properties of refinedhypereutectic aluminum-silicon alloys. In the present work, by using a stepped-form mold and thehydrogen-detecting instrument HYSCAN II, the relationshi...Dissolved hydrogen is harmful to mechanical properties of refinedhypereutectic aluminum-silicon alloys. In the present work, by using a stepped-form mold and thehydrogen-detecting instrument HYSCAN II, the relationship between the initial hydrogen content inthe melt and the refinement effect on the casting of hypereutectic aluminum-silicon alloy wasinvestigated. The experimental results show that the cooling rate, the hydrogen content and thegrain refinement effect are three interactive factors. When the hydrogen content is above 0.20mL/100 g and the cooling rate is lower than that in 50 mm-thick step, hydrogen dissolved in thealloy melt influences the grain refinement effect. With increasing the cooling rate, the criticalhydrogen content increases too. It is expected that much hydrogen in the melt make the netinterfacial energy larger than or equal to zero, resulting in the shielding of the particles AlPduring solidification and that the critical gas content is closely related to the critical radius ofembryo bubbles.展开更多
Under the driving force of the“carbon cycle”goals,achieving efficient synthesis and precise functional regulation of catalytic materials while simultaneously addressing CO_(2) resource utilization and environmental ...Under the driving force of the“carbon cycle”goals,achieving efficient synthesis and precise functional regulation of catalytic materials while simultaneously addressing CO_(2) resource utilization and environmental friendliness has become a central challenge in the fields of energy catalysis and pollution control.Traditional synthesis methods often face issues such as insufficient precision in microstructure regulation,high energy consumption in processes,and solvent pollution,while the inadequate exposure of active sites and low mass transfer efficiency of CO_(2) conversion catalysts further hinder their large-scale application.In response to these challenges,supercritical carbon dioxide(sc-CO_(2))technology,leveraging its unique physicochemical properties and green process characteristics,offers an innovative solution for the multi-scale structural design and performance optimization of catalytic materials.This review systematically analyzes the mechanisms by which sc-CO_(2) technology regulates micro/nano structures(e.g.,defect engineering,hierarchical pore construction),modifies active sites(e.g.,heteroatom doping),and enhances reaction kinetics in the synthesis of photo/electrocatalysts,revealing its key role in improving CO_(2) reduction efficiency,pollutant degradation rates,and sensor sensitivity.Furthermore,it highlights that,future advancements in machine learning-driven process optimization,single-atom catalyst design,and reactor fluid dynamics innovation can overcome current limitations such as sensitivity to pressure-temperature conditions and insufficient material stability.This review provides a theoretical framework for developing sc-CO_(2) synthesis technologies that combine atomic-level precision control with industrial feasibility,thereby advancing clean energy conversion and low-carbon manufacturing.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No.50071028)the Natural Science Foundation of Shandong Province in China (No. Z2001F02)
文摘Dissolved hydrogen is harmful to mechanical properties of refinedhypereutectic aluminum-silicon alloys. In the present work, by using a stepped-form mold and thehydrogen-detecting instrument HYSCAN II, the relationship between the initial hydrogen content inthe melt and the refinement effect on the casting of hypereutectic aluminum-silicon alloy wasinvestigated. The experimental results show that the cooling rate, the hydrogen content and thegrain refinement effect are three interactive factors. When the hydrogen content is above 0.20mL/100 g and the cooling rate is lower than that in 50 mm-thick step, hydrogen dissolved in thealloy melt influences the grain refinement effect. With increasing the cooling rate, the criticalhydrogen content increases too. It is expected that much hydrogen in the melt make the netinterfacial energy larger than or equal to zero, resulting in the shielding of the particles AlPduring solidification and that the critical gas content is closely related to the critical radius ofembryo bubbles.
基金supported by National Natural Science Foundation of China(grant Nos.32071323,32271410)the Science and Technology Projects in Fujian Province(grant Nos.2022FX1,2023Y4008)+2 种基金the Scientific Research Funds of Huaqiao University(grant No.23BS108)the Open Research Fund of Academy of Advanced Carbon Conversion Technology of Huaqiao University(grant No.AACCT0004)Program for Innovative Research Team in Science and Technology in Fujian Province University.
文摘Under the driving force of the“carbon cycle”goals,achieving efficient synthesis and precise functional regulation of catalytic materials while simultaneously addressing CO_(2) resource utilization and environmental friendliness has become a central challenge in the fields of energy catalysis and pollution control.Traditional synthesis methods often face issues such as insufficient precision in microstructure regulation,high energy consumption in processes,and solvent pollution,while the inadequate exposure of active sites and low mass transfer efficiency of CO_(2) conversion catalysts further hinder their large-scale application.In response to these challenges,supercritical carbon dioxide(sc-CO_(2))technology,leveraging its unique physicochemical properties and green process characteristics,offers an innovative solution for the multi-scale structural design and performance optimization of catalytic materials.This review systematically analyzes the mechanisms by which sc-CO_(2) technology regulates micro/nano structures(e.g.,defect engineering,hierarchical pore construction),modifies active sites(e.g.,heteroatom doping),and enhances reaction kinetics in the synthesis of photo/electrocatalysts,revealing its key role in improving CO_(2) reduction efficiency,pollutant degradation rates,and sensor sensitivity.Furthermore,it highlights that,future advancements in machine learning-driven process optimization,single-atom catalyst design,and reactor fluid dynamics innovation can overcome current limitations such as sensitivity to pressure-temperature conditions and insufficient material stability.This review provides a theoretical framework for developing sc-CO_(2) synthesis technologies that combine atomic-level precision control with industrial feasibility,thereby advancing clean energy conversion and low-carbon manufacturing.
