Catalytic Hydrolysis of Perfluorinated Compounds in a Yolk-Shell Micro-Reactor

Perfluorinated compounds (PFCs) are emerging environmental pollutants characterized by their extreme stability and resistance to degradation. Among them, tetrafluoromethane (CF₄) is the simplest and most abundant PFC in the atmosphere. However, the highest C─F bond energy and its highly symmetrical structure make it particularly challenging to decompose. In this work, a yolk-shell Al₂O₃ micro-reactor is developed to enhance the catalytic hydrolysis performance of CF₄ by creating a local autothermic environment. Finite element simulations predict that the yolk-shell Al₂O₃ micro-reactor captures the heat released during the catalytic hydrolysis of CF₄, resulting in a local autothermic environment within the yolk-shell structure that is 50 °C higher than the set temperature. The effectiveness of this local autothermic environment is experimentally confirmed by in situ Raman spectroscopy. As a result, the obtained yolk-shell Al₂O₃ micro-reactor achieves 100% CF₄ conversion at a considerably low temperature of 580 °C for over 150 h, while hollow and solid Al₂O₃ structures required higher temperatures of 610 and 630 °C, respectively, to achieve the same conversion rate, demonstrating the potential of yolk-shell Al₂O₃ micro-reactor to significantly reduce the energy requirements for PFCs degradation and contribute to more sustainable and effective environmental remediation strategies.