DOI: 10.1002/cctc.201200483 Heterogeneous Catalysis: A Key Tool toward Sustainability Claude Descorme, Pierre Gallezot,* Christophe Geantet, and Christian George [a] 1. Introduction The history of heterogeneous catalysis started with the synthe- sis of sulfuric acid in the 18 th century, well before the word cat- alysis was coined and its concept defined. While in the 1970s most of the Academic literature and industrial processes fo- cused on applications in oil refining and synthesis of bulk chemicals, the field of application of heterogeneous catalysis expended rapidly during the recent decades. Heterogeneous catalysis is still the key tool for the conversion of petroleum and natural gas into cleaner and more efficient fuels, but it is now also instrumental for the production of alternative fuels such as hydrogen and biofuels. Heterogeneous catalysts are still used massively to produce bulk chemicals, but they are now also employed for the selective synthesis of intermediates, specialties, and fine chemicals. This was made possible by major advances in the design of catalysts at the molecular level, e.g., by combining the advantages of nanostructured solids and grafted organometallic complexes. Heterogeneous processes are now playing a major role in the burgeoning R&D aimed at developing the use of biomass as a substitute for fossil resources in the production of fuels and products. [1] The most rapid and visible change from an industrial standpoint was the development of environmental catalysis for the treat- ment of harmful gases and particles emitted into the atmos- phere by anthropogenic activities. Catalytic and photocatalytic processes are gaining in importance for the treatment of or- ganic pollutants present in drinking or wastewater, thus contri- buting to health and environmental preservation. Household catalytic appliances are also being developed for indoor air cleaning and in unexpected domains. Finally, environmental scientists are realizing that the global destruction of nitrogen oxides and organic molecules present in the earth atmosphere is mainly due to natural processes catalyzed by mineral dust from deserts, which, as suggested by Zamaraev, could serve as kidneys for the earth. [2] This article does not aim at reviewing the spectroscopic, mi- crokinetics, and theoretical methods, which were essential for understanding the molecular mechanisms on catalyst surfaces, nor the major advances in catalyst and reactor design, which improved the activity, selectivity, and stability with time of cat- alytic processes. Selected examples spanning from clean and alternative fuel production and chemical synthesis to the abatement of pollutants in air, water, and high atmosphere will be given to illustrate the benefit of heterogeneous catalysis for a sustainable development. 2. Clean and Alternative Fuels 2.1. Improved use of petroleum resources During the 20th century, oil refining technologies were contin- uously improved to provide cleaner fuels, greater product yields and energy efficiency. More than half of oil production (80 Mbbl per day) is dedicated to transportation. The conver- sion and purification technologies used for fuel production are based on heterogeneous catalysis, which accounts for more than 90 % of oil refining processes. Developed countries have adopted drastic legislation on sulfur regulation, octane and cetane numbers leading to better fuels. Combined with the use of new engines, these efforts resulted in less fuel con- sumption and toxic emissions such as SO x and soot. Because the demand on transportation fuels is continuously increasing, the R&D in these classic aspects of refining is still very active. Fluid catalytic cracking (FCC), the most important process in re- fineries is consuming more than 450 kt per year of catalysts based on a sophisticated mixture of zeolite, matrix, filler, binder and additives, such as metal passivators. [3] The second important class of refining catalysts is composed of hydrotreat- ing and hydrocracking sulfide catalysts. Hydrodesulfurization (HDS) is able to achieve 99.9 % conversion of sulfur com- [a] Dr. C. Descorme, Dr. P. Gallezot, Dr. C. Geantet, Dr. C. George Institut de recherches sur la catalyse et l’environnement (IRCELYON) UniversitØ de Lyon, CNRS, UMR 5256 2, avenue Albert Einstein, 69626 Villeurbanne (France) E-mail : pierre.gallezot@ircelyon.univ-lyon1.fr The scope of this concept article is to demonstrate through few selected examples taken from recent literature that hetero- geneous catalysis is presently an essential tool to achieve a sus- tainable use of resources for energy, chemical, and material production and to preserve and rehabilitate our environment. Using heterogeneous catalysts for the production of fuels and chemicals reduce the energy demand and minimize the forma- tion of non-recyclable wastes by increasing the activity and se- lectivity of fossil and renewable resource conversion. It is now the essential tool for the treatment of pollutants in air and water. The efficiency of photocatalytic processes for the treat- ment of toxic compounds in air and water is also highlighted. The destruction of pollutants by mineral dust in the atmos- phere demonstrates the major role that heterogeneous catalyt- ic processes plays for global environmental preservation. ChemCatChem 0000, 00, 1 – 11  2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim &1& These are not the final page numbers! ÞÞ