Editorial [ Hot Topic: Combinatorial Heterogeneous Catalysis (Part 2) (Guest Editor: Jozsef L. Margitfalvi) ]

These special issues (Vol. 10, No. 1 and Vol. 10, No. 2) are devoted to progress in the area of Combinatorial Heterogeneous Catalysis (CHC), which can be considered to be the general application of combinatorial and high-throughput methods and strategies in materials research. Heterogeneous catalysis plays a vital role if our everyday lives. All pollution-free and environmentally friendly industrial processes in oil refineries, chemical plants, and power energy stations need highly active and selective catalysts. Catalysts are used in cars and trucks to remove harmful products of incomplete oxidation of gasoline or diesel fuel. The plastics used in everyday life are prepared by applying very specific highly active and selective catalysts, and this list can be continued. Better catalysts reduce productions costs, reduce the formation of wasteful by-products, and help to decrease atmospheric pollution. These are the main reasons that the search for new and better catalysts is a permanent R & D task. In general, combinatorial approaches are intended to find the optimum formulation in various pharmaceutical or engineering materials including catalysts, with the shortest interval and minimum amount of unit cost. In this case the focus is laid on the optimum performance with decreased overall costs. All combinatorial approaches are based on the diversity of the system investigated. This diversity determines the parameter space where the optimum performance may be found. In combinatorial materials research, including CHC, the following key components of diversity can be distinguished: (i) compositional; (ii) process; and (iii) structural. The structural diversity is determined by the first two components. In order to move in a large experimental space towards the optimum performance, the following requirements must be fulfilled: (i) high throughput methods in synthesis, testing, and analysis; (ii) highly reliable and reproducible analytical methods; (iii) effective optimization and information mining tools; and (iv) appropriate data handling and management methods. Today, combinatorial heterogeneous catalysis is a well-acknowledged area of catalysis sciences, although a definite part of our scientific community still remains quite critical. Methods of combinatorial catalysis are widely used both in applied and academic laboratories. Symyx Technologies was the first company devoted to the area of combinatorial heterogeneous catalysis. Among the followers are the Dutch company Avantium Technologies, the German group “hte GmbH”, etc. In the last 10 years, most of the large oil and chemical companies created their own laboratories in combinatorial catalysis. In academia, various combinatorial heterogeneous laboratories have emerged in various countries, such as Australia, Japan, Korea, Singapore, Germany, the Netherlands, Belgium, France, UK, Norway, Spain, Hungary, Canada, USA, China, India, and Mexico. These laboratories may be considered as the pioneers in this field. Consequently, there is considerable geographical diversity in the location of key laboratories. The importance of this field has been documented by various international meetings fully or partly devoted to CHC. Most of the international meetings in the field of heterogeneous catalysis have an independent section devoted fully to high throughput and combinatorial methods. In several highly ranked meetings (Europacat, International Catalysis Congress), round table discussions took place that were excellent forums for listening to both the pros and the cons of CHC. It should be mentioned that there is a special “heterogeneous catalysis” section at the Gordon Research Conferences devoted to the field of combinatorial materials research. If we look back to the first publications in the area of CHS, we see that the focus has been on the methodology and the use of high-throughput techniques and technologies. In this period, gas phase catalytic reactions were usually investigated. Today, after ten years of practice in this field, the area of activity in CHC has been expanded considerably.......