I. INTRODUCTION he name ‘catalysis’ was coined by Berzelius in 1836 [1]. Many types of materials can serve as catalysts. These include metals, metal compounds (e.g., metal oxides, sulfides, nitrides), organometallic complexes, and enzymes. It is generally accepted that catalysis plays a fundamental role in the industries. Specifically, two of the largest industry segments, chemicals and petroleum processing, depend on catalysis; many of the modern, cost-and energy-efficient environmental technologies are catalytic; and biocatalysis offers exciting opportunities for producing a broad range of pharmaceuticals and specialty chemicals, and for bioremediation of the environment. A large fraction of chemical, refinery, and pollution-control processes involve catalysis. Catalysis is critical in the production of 30 of the top 50 commodity chemicals produced in the U.S. and many of the remaining ones are produced from chemical feedstock based on catalytic processes. In broader terms, nearly 90% of all U.S. chemical manufacturing processes involve catalysis [2]. Catalysts are classified as homogeneous if they are present in the same phase as the reagents. This normally means that catalysts are present as solutes in a liquid reaction mixture. Catalysts are heterogeneous if they are present in a different phase. Heterogeneous catalytic reaction systems, in which fluid reactants are passed over solid catalysts, are at present the most widely used catalytic processes in the manufacturing industries. Solid, heterogeneous catalysts have the advantages of ease of recovery and recycling and readily amenable to continuous processing. The selectivity and activity of homogeneous catalysts under mild reaction conditions is unbeaten by their heterogeneous counterparts. Unfortunately, the problem of separating the single-site-catalysts from the reaction media is still an important drawback which blocks large scale applications in industry. Only a few processes are applied nowadays in industry, such as the production of adiponitrile by Dupont, acetic acid by Monsanto and butanal by Celanese (former Ruhr Chemie) [3]. In each case an individual solution was developed to solve the problem of catalyst separation and recovery. A general toolbox for this has to be filled. In Table 1, the advantages and disadvantages of homogeneous versus T IBNU SINA INSTITUTE FOR FUNDAMENTAL SCIENCE STUDIES, UNIVERSITI TEKNOLOGI MALAYSIA 14 March 2008 Heterogeneous Chemocatalysis: Catalysis by Chemical Design - A Personal Experience Hadi Nur* http://www.hadinur.com *Correspondence: Dr. Hadi Nur Ibnu Sina Institute for Fundamental Science Studies Universiti Teknologi Malaysia 81310 UTM Skudai Johor, Malaysia Tel.:+60 7 5536077 Fax:+60 7 5536080 E-Mail: hadi@ibnusina.utm.my This author started his research activity on heterogeneous catalysis in 1995 as a Ph.D. student at Universiti Teknologi Malaysia. He tackled a project on the synthesis, characterization and catalytic activity of ultra-large pore of aluminophoshate molecular sieves, VPI-5, just recently successfully synthesized by Prof. Mark Davis and his co-workers. After six months experimental work, the author failed to synthesize VPI-5. Everything in the auhor’s Ph.D. thesis comes from the last twelve months in the laboratory. Nonetheless, since the author had another project on synthesis of zeolite from rice husk ash that both worked at once, he ended up with three international publications together on the study of the structure, physicochemical properties and catalytic activity of metal- substituted AlPO 4 -5. This author also proposed and successful in synthesizing NaA zeolite directly from rice husk and carbonaceous rice husk ash. He finally found out what independently doing good science. It was an exhilarating period. The author finished his Ph.D. project in two and half years in 1998. The author continued work as a postdoctoral fellow for one year at Universiti Teknologi Malaysia. In 1999, the author was fortunate enough to land a postdoctoral position at Catalysis Research Center, Hokkaido University, Japan. In two years as JSPS (Japan Society for the Promotion of Science) Postdoctoral Fellow and continued stay as COE (Center of Excellent) visiting researcher at Catalysis Research Center for half year, the author published a seminal paper on a new concept in heterogeneous catalysis termed “Phase-boundary catalysis”. During stay in Japan, the author learns how to do science right. In May 2002, for one year, the author joined the Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia as research officer and in 2003 he accepted his first academic position as lecturer at this university. In this review, an attempt will be made to classify several heterogeneous catalytic systems which contain examples from the author’s experience in this research area. The author’s scientific research in heterogeneous catalysis has been classified into five classes: single center catalyst, hydrophobic-hydrophilic catalytic system, bifunctional catalyst, synergetic multi reaction center catalyst and photocatalyst. The catalysts have been designed for synthesis of useful organic compounds. For detailed information on the research projects and for acquiring some knowledge on research in the covered fields the reader is referred to the pertinent recent publications and references therein.