The particles of heterogeneous catalysts differ greatly in size,morphology,and most importantly,in activity.Studying these catalyst particles in batch typically results in ensemble averages,without any information at ...The particles of heterogeneous catalysts differ greatly in size,morphology,and most importantly,in activity.Studying these catalyst particles in batch typically results in ensemble averages,without any information at the level of individual catalyst particles.To date,the study of individual catalyst particles has been rewarding but is stll rather slow and often cumbersomel.Furthermore,these valuable in-depth studies at the single particle level lack statistical relevance.Here,we report the development of a droplet microreactor for high-throughput fluorescence-based measurements of the acidities of individual particles in fluid catalytic cracking(FCC)equilibrium catalysts(ECAT).This method combines systematic screening of single catalyst particles with statistical relevance.An oligomerization reaction of 4-methoxystyrene,catalyzed by the Bronsted acid sites inside the zeolite domains of the ECAT particles,Was performed on-chip at 95 ℃.The fluorescence signal generated by the reaction products inside the ECAT particles was detected near the outlet of the microreactor.The high-throughput acidity screening platform was capable of detecting~1000 catalyst particles at a rate of 1 catalyst particle every 2.4 s.The number of detected catalyst particles was representative of the overall catalyst particle population with a confidence level of 95%.The measured fluorescence intensities showed a clear acidity distribution among the catalyst particles,with the majority(96.1%)showing acidity levels belonging to old,deactivated catalyst particles and a minority(3.9%)exhibiting high acidity levels.The latter are potentially of high interest,as they reveal interesting new physicochemical properties indicating why the particles were still highly acidic and reactive.展开更多
基金supported by the Netherlands Center for Multiscale Catalytic Energy Conversion(MCEC),an NWO gravitation program funded by the Ministry of Education,Culture and Science of the government of the Netherlands.The authors would like to acknowledge Jan van Nieuwkasteele(University of Twente)for his invaluable help in setting up the Hamamatsu camera and attached computer,which enabled fast data processing for fluorescencedetection.
文摘The particles of heterogeneous catalysts differ greatly in size,morphology,and most importantly,in activity.Studying these catalyst particles in batch typically results in ensemble averages,without any information at the level of individual catalyst particles.To date,the study of individual catalyst particles has been rewarding but is stll rather slow and often cumbersomel.Furthermore,these valuable in-depth studies at the single particle level lack statistical relevance.Here,we report the development of a droplet microreactor for high-throughput fluorescence-based measurements of the acidities of individual particles in fluid catalytic cracking(FCC)equilibrium catalysts(ECAT).This method combines systematic screening of single catalyst particles with statistical relevance.An oligomerization reaction of 4-methoxystyrene,catalyzed by the Bronsted acid sites inside the zeolite domains of the ECAT particles,Was performed on-chip at 95 ℃.The fluorescence signal generated by the reaction products inside the ECAT particles was detected near the outlet of the microreactor.The high-throughput acidity screening platform was capable of detecting~1000 catalyst particles at a rate of 1 catalyst particle every 2.4 s.The number of detected catalyst particles was representative of the overall catalyst particle population with a confidence level of 95%.The measured fluorescence intensities showed a clear acidity distribution among the catalyst particles,with the majority(96.1%)showing acidity levels belonging to old,deactivated catalyst particles and a minority(3.9%)exhibiting high acidity levels.The latter are potentially of high interest,as they reveal interesting new physicochemical properties indicating why the particles were still highly acidic and reactive.
