Biography

Dr. Hervé Toulhoat, born april 1954, received his Chemical Engineering degree from the Paris School of Chemistry (now Chimie Paristech) in 1976, then went on to earn his PhD from the Paris School of Mines (Mines Paristech) in 1980. In 2002, Dr. Toulhoat received his Habilitation from University Pierre et Marie Curie (Paris VI).

Dr. Toulhoat was the Deputy Scientific Director of IFP Energies nouvelles (IFPEN) until his retirement (December 31^st, 2016). Since joining IFP in 1980, Dr. Toulhoat has served numerous positions, including: research Scientist, then Project Manager "Basic and Exploratory Research in Hydrotreatments", Division Kinetics and Catalysis, (1980-1987); head of the Department of Physical Chemistry of Interfaces (1987-1992); in charge of the Molecular Modelling Group, Division of Computer Science and Applied Mathematics (1995-2000); director of the "European GdR" CNRS G12090 "Dynamique moléculaire quantique appliquée à la catalyse, l'adsorption et l'absorption" (1996-2003); IFP Associate Research Director (1998-2005); director of Doctoral Studies at IFP School  (2001-2012) ; In charge of IFPEN exploratory research (May 1998-2016).

Dr. Toulhoat also spent time at Total Raffinage Distribution (1993-1994) as a Scientific Consultant, in charge of developing molecular modelling.

His teaching activities have included: organization of IFP School Doctoral College Conferences (2001-2012); lectures on molecular modelling for various Masters of Science (Paris, Marne la Vallée, Lyon) (1995-present) and at IFP School on hydrotreating catalysts and processes (1982-1987).

Dr. Toulhoat's current research topics are applications of molecular modelling and computational chemistry in catalysis, while his fields of competence include Catalysis, Chemistry, Physical Chemistry of Surfaces and Interfaces, Chemical Engineering, Refining and Petrochemistry, Molecular Modelling, and Theoretical Chemistry.

In addition to serving on the Editorial Board of “Journal of Catalysis” since 2005, Dr. Toulhoat is also a member of the Editorial Board of l'Actualité Chimique, a member of the Société Chimique de France, active in the board of the “interdivision énergie”, and a member of the executive scientific committee of IUPAC 2019.

Dr. Toulhoat has authored or co-authored 133 publications, (h-index Google Scholar 47 [1])  and 24 patents, has directed 14 doctoral theses, and coordinated 7 books or proceedings. He has been invited several times as keynote speaker to international conferences : EUROPACAT VIII, FOMMS 2009, CIMAT 2008, MIGRATION 05, OXYSOL 2005, NCCC VII, etc… He has organized or co-organized several international workshops. He has been promoter and coordinator of 5 international or national large collaborative projects and active member of 2 more.

Dr. Toulhoat has also been the recipient of a number of awards, including the following: Chevalier de l'Ordre National du Mérite (2005), Prix Michonsniky of Chimie Paristech alumni (1988), and Silver Medal, "Société pour l'Encouragement de l'Industrie Nationale" (1985).

Main contributions in hydrotreating catalysis

As he joined IFP in 1980, Hervé Toulhoat became fascinated by the multiple open questions debated in the international research community devoted to catalysis by transition metal sulfides (TMS) and its application to hydrocarbons refining: to quote only the most crucial,

1) how could we understand the periodic trends in hydrodesulfurization (HDS) by TMS?

2) What is the origin of the "synergy effect" by which adding Ni or Co to Mo or W in the formulation of catalysts may results in a 100 fold increase in activity?

3) What is the structure of those TMS active phases? 

4) Where are the active sites and what is their local structure? 

5) What is their relationship to the support, mostly g-alumina?

6) What is exactly the structure of g-alumina?

Beside his applied research (contributions detailed in the  “list of achievments”), he has devoted most of his scientific life in the past 3 following decades to contribute answering these enigmas. In this quest I was mainly helped by my three most brilliant PhD students, now colleagues at IFPEN: Dr Slavik Kasztelan who graduated in 1984 from University of Lille, Dr Pascal Raybaud, who graduated in 1998 jointly from Universities of Paris and Vienna (Austria), and Dr Mathieu Digne, who graduated in 2004 from University of Lyon.

Hervé proposed the original ideas addressing questions 3) and 4), leading to the publication in 1984 of the so-called "geometrical model" of the active phase of hydrotreating catalysts [1], cited more than 300 times so far, which for the first time proposed a rational explanation of the "magic" ratios Co(Ni)/Mo(W) allowing to formulate optimal hydrotreating catalysts. The key concept was to locate active sites at the edges (M­-edge and S-­edge for symmetry reasons) of supported lamellar Mo(W)S₂ nanoparticles, the so called "CoMoS" of "NiMoS" phases.

A few years later, Hervé had the opportunity to develop a research project based on emerging numerical simulation tools in chemistry, including efficient first principles methods based on the Density Functional Theory (DFT).  Pascal Raybaud spent years 1995 and 1996 with Prof. J. Hafner's group in Vienna, in order to acquire a deep knowledge of DFT and the Vienna Ab initio Simulation Package (VASP).  Hervé proposed him to address first question 1), in that time dominated by the "Bond energy Model" of H. Topsoe and J.K. Norskov. The alternative explanation ensued in 1996, with the first DFT descriptor of a "volcano curve" in coherence to what was expected from the Sabatier principle. This communication has been cited 134 times. It was complemented by other highly cited papers also cited more than 100 times.

The solution of question 2) came as an obvious consequence of our volcano curve, but is was further substantiated by local studies in relation with questions 3) and 4) as mentioned below. Our original concept of DFT descriptor for bulk crystalline solids was precisely defined as the "Yin-Yang" bond strength, related to surface bond strengths and formal micro-kinetics, and generalized to other catalytic reactions involving hydrocarbons in [2], cited 128 times. From this concept and related patents, the module Predibond™ for in-silico search of potential catalytic materials is being distributed by the software company Materials Design Inc.

Questions 3) and 4) were revisited under the light of DFT together with question 2), leading to numerous highly cited papers, the first of which historically appearing in physical Review letter in 1998 was cited 118 times, and the last appeared in 2011 [3], already cited 4 times  

Question 6) had to be addressed before 5), and it was beautifully solved leading in 2004 to the non-spinel model of g-Al₂O₃ and its surface properties [4], cited 463 times.

Question 5) was then treated, still thanks to DFT, in four papers published between 2005 and 2007 an totalling already about 200 citations.

Lately, Hervé Toulhoat planned, coordinated, edited and largely co-authored a book, published in 2013 [5], the first part of which presents the results of his group, based mostly on DFT, but making the best use of available complementary surface science and experimental kinetic informations. The second part, devoted to preparation and characterization methods of industrial hydrotreating catalysts, demonstrates the rationalizing impact of the new insight brought by this modelling effort: it clearly contributed to the observed improvement of commercial HDS catalysts activities by more than a factor 2 within the past 15 years (Figure 0.1 of [5]).

[1] Kasztelan, S; Toulhoat, H; Grimblot, J; Bonnelle, J.P. "A geometrical model of the active phase of hydrotreating catalysts", Applied Catalysis, Volume 13, Issue 1, pages 127-159  (1984).

[2] Toulhoat, H; Raybaud, P. "Kinetic interpretation of catalytic activity patterns based on theoretical chemical descriptors", Journal of Catalysis, Volume 216, Issue 1-2, Pages 63-72  (2003).

[3] Prodhomme, P.Y.; Raybaud, P.; Toulhoat, H.  "Free-energy profiles along reduction pathways of MoS2 M-edge and S-edge by dihydrogen: A first-principles study", Journal of Catalysis, Volume 280, Issue 2, Pages 178-195 (2011).

[4] Digne, M; Sautet, P; Raybaud, P; Euzen, P.; Toulhoat, H. "Use of DFT to achieve a rational understanding of acid-basic properties of gamma-alumina surfaces" Journal of Catalysis, Volume 226, Issue 1, Pages 54-68  (2004).

[5] Toulhoat, H.; Raybaud, P. (Editors) "Catalysis by Transition metal Sulfides, From molecular Theory to Industrial applications", Editions Technip, Paris, (2013) 832 pages.