کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
60646 47540 2016 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Irreversible deactivation of hollow TS-1 zeolite caused by the formation of acidic amorphous TiO2–SiO2 nanoparticles in a commercial cyclohexanone ammoximation process
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Irreversible deactivation of hollow TS-1 zeolite caused by the formation of acidic amorphous TiO2–SiO2 nanoparticles in a commercial cyclohexanone ammoximation process
چکیده انگلیسی


• The deactivated HTS zeolite still remains well texture and morphology.
• Part framework Ti species are transformed into amorphous TiO2–SiO2 nanoparticles.
• Amorphous TiO2–SiO2 nanoparticles have Brönsted and Lewis acid property.
• Acidic TiO2–SiO2 nanoparticles favor accelerating the decomposition of H2O2.
• The irreversible deactivation of HTS zeolite is caused by H2O2 decomposition.

Commercial deactivated HTS zeolite has been investigated by multiple characterization methods and catalytic evaluations. These indicate that structural and textural properties are not mainly ascribed to the irreversible deactivation, but some framework Ti species are transformed into Ti-rich nanoparticles. Both Brønsted and Lewis acid sites are observed in deactivated HTS zeolite, which agrees well with the spectroscopic characterization results and Tanabe’s acidity theory on mixed binary oxides. Hence the acidic Ti-rich aggregates are attributed to the amorphous TiO2–SiO2 nanoparticles located on the external surface of the zeolite. Furthermore, it is demonstrated that the catalytic performance of deactivated HTS zeolite in phenol hydroxylation is seriously dependent on its acidity properties, which can accelerate the decomposition of H2O2. As a consequence, we conclude that the irreversible deactivation of HTS zeolite in the ammoximation process is caused by the formation of acidic amorphous TiO2–SiO2 nanoparticles catalyzing the fast H2O2 decomposition reaction.

Figure optionsDownload high-quality image (177 K)Download as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 338, June 2016, Pages 340–348
نویسندگان
, , , , , , ,