TKP2 Heterogen katalyse VK Heterogeneous Catalysis Advanced Course Purpose: Specialization in Heterogeneous Catalysis Goal: Prepare the students to –Learn more about (heterogeneous) catalysis –Understand and assess reported experimental work –Plan and interpret own experiments –Provide training in reporting Involving –Knowledge of theory, and theoretical limitations –Knowledge of practical methods –Training in presentation (written and oral) Expected effort: –3,75 STP, i.e. approx. 1/8 semester, or 120 hours –< 10 hours lectures –Main part: Own studies, work with projects (vide infra) and preparation for exam Assessment: Oral examination + excercise (written + oral part)

Seminars/topics/dates Topic 1: Introduction Wed Sep 10 13:15 -(K24) Topic 2: Materials Wed Sep 10 13:15 -(K24) Topic 3: Characterization Wed Sep :15- (K5-323) Topic 4: Kinetics Tue Sep :15- (K5-323) Topic 5: Activity measurements Wed Sep :15- …(K24) Topic 6: Deactivation Wed Sep :15- …(K24)

Heterogeneous catalysis Different disciplines or points of view: –Kinetics (Reaction engineering) –Materials and synthesis (Inorganic chemistry) –Characterization (and detailed understanding, mechanism) (Instrumental analysis, surface science) Catalysis can (must!) be studied at several levels: –Microscopic (atomic level) –Mesoscopic (nano-micrometer level) –Macroscopic (reactor -process level)

Common fundament: General chemistry, inorganic chemistry Chemical Reaction Engineering and earlier subjects (including ”Prosessteknikk” (Intr. Chem.Eng.) and Physical Chemistry): –Mass- and energy balances, kinetics, reactor design –In particular Chem. Reaction Engineering (Textbook: Scott Fogler) Chap. 10: catalysis, definitions, rate, rate limiting step (rds) Reaction kinetics and catalysis –Emphasis on heterogeneous catalysis

Basics Definition: –A catalyst increases the rate of a (desired) chemical reaction without being consumed in the reaction –Does not influence the equilibrium Terms –Activity, selectivity, life-time –Classification according to type of material Reaction rate –Defined for different units (based on catalyst volume, weight, total area, specific area, turnover) –global, local rate (intrinsic rate)

Continued... Mechanisms –Elementary steps –Rate determining reaction step (rds) –PSSA Adsorption amd desorption –Physical adsorption, chemisorption –Lennard Jones-diagram, heat of adsorption, activation energy –isotherms (Langmuir, etc.) Chemisorption and determination of dispersion of supported metal catalysts

Continued further... Catalytic mechanisms –Adsorption, desorption rate determining E.g. NH 3 -synthesis (adsorption, applying the Temkin isotherm) –Surface reaction is rds Power rate law, LH, LHHW Bimolecular reactions (LH, Eley-Rideal, Mars - van Krevelen) –Temperature dependancy, activation energy, heat of adsorption Mass transport –diffusion (bulk, Knudsen) –diffusion and reaction, effectiveness factor, Thiele modulus –particle external mass transfer limitations –all those above linked to kinetics

Still continuing…. Catalyst deactivation –Different deactivation mechanisms Catalyst materials –metals, oxides, zeolites… Activity-selectivity-lifetime measurements (”catalyst testing”) –Laboratory reactors Some of these topics were given only a brief treatment previously and are also included here

Teaching and curriculum Contents summarized in lectures/seminars : –Materials –Characterization –Kinetics –Transport/testing –Deactivation Curriculum literature –Slides, textbooks, papers etc. Individual excercise –Each student gets a journal article on catalysis to study carefully –2 parts to the excercise: 1.Write an essay discussing the fundamental theory and practice of catalysis in the article. See next slide for points to be included. 2.Present the content of the article in a scientific presentation (for the rest of the group)– pretend to be the author of the paper! –Both parts will count towards the mark in the course (30% of the module)

Read the article carefully and write a report (essay) describing carefully – including the key theory (equations and assumptions) and practical issues (how are the experiments done), covering: –Which chemical reaction is studied, the background (why is it interesting), thermodynamics (heat of reaction, equlibrium) –Type of catalyst (material, form) –If catalyst materials are prepared: Preparation and material issues –Characterization surface area and porosity structure and morphology Dispersion –How are the activity measurements done (reactor, experimental plan), calculations, how is deactivation handled etc. –If necessary (e.g. something unclear) gather further information from the references in the paper or other sources. Sometimes experimental details are given in earlier papers by the same authors. –Do not focus on the scientific findings!! Essay

Presentation Prepare and perform an oral presentation of the article you have been given –Pretend you are the scientist (PI) behind the work –Give a scientific presentation Background Methods Theory Results and discussion Conclusions –Be prepared to answer questions about the methods used in the paper

Suggested dates and deadlines Hand in essay: Monday November 3 Seminar(s) with presentations: –Tuesday November 18 13:15 … (K5- 201) –Wednesday November 19 13:15… (K5- 201) Exam: Dec. 3