“Environmentally conscious” materials, or “ecomaterials,” are those specifically designed to minimize adverse effects on the environment while maintaining acceptable performance and a competitive price. Related terms include “environmentally friendly” materials, or “environmentally preferable” materials, which are essentially synonymous. A notable geographic trend was observed in relation to this terminology: a recent computer search of the scientific literature under “ecomaterials” produced eight hits, all from authors in Asia, while “environmentally friendly materials” produced six hits, primarily from authors in North America and Europe.

The final decade of the 20th century was the most important period yet in establishing a sustainable society for the coming century. After the Earth summit held in Rio de Janeiro in 1992, the world's population was challenged to decrease its environmental impact on the Earth. Nine years after the Rio summit, we are living in a more dangerous and unsustainable world with a higher population, more resource consumption, more waste, and more poverty, but with less biodiversity, less forest area, less available fresh water, less fertile soil, and less stratospheric ozone.

Early in the 1990s in the United States, a series of legislative measures were proposed for banning the use of lead for many applications in industries involving electronic solders. Although electronic solders were ultimately exempted, this argument ignited worldwide concern, and research began on the development of lead-free solders. The U.S. project, organized by the National Center for Manufacturing Sciences (NCMS), was carried out from 1992 to 1996. Major electronics companies and auto manufacturers participated with several national institutes in this project.

Catalysts based on cerium oxide are now used as effective oxidation systems in numerous environmental applications. Cerium oxide was introduced into the catalysis field relatively recently, in 1976, and not as a catalyst initially. Rather, it was chosen as the key oxygen-storage component of the three-way catalyst (TWC) used in automotive exhausts. Accordingly, ceria is used to extend the air/fuel ratio window in the exhaust gas, releasing or accepting oxygen, respectively, under fuel-rich or fuellean conditions, so that the noble metal catalyst operates at the desirable stoichiometric air/fuel ratio, at which it effectively converts all three gaseous pollutants—CO, hydrocarbons, and NO—to innocuous products. A solid solution of cerium and zirconium oxides is used in today's catalytic converters because of its higher oxygen-storage capacity (OSC) compared with pure ceria. In the years that followed the introduction of ceria into the catalytic converter, many additional merits of cerium oxide were realized, first as an active catalytic component of the TWC and subsequently as a catalyst and sorbent in various industrial applications. A review article by Trovarelli on ceria-based catalysts is a good recent compilation.

Activated carbons are the most important carbon materials used in water treatment. Their known world production is around 500,000 tons per year, of which about 80% is used for liquid-phase applications. These solids are manufactured in powder or granular form from a large variety of raw materials and are unique and versatile adsorbents due to their highly developed porosity, their large surface area (which in some cases can be up to 3000 m2/g), and their variable surface chemistry.

It is not an overstatement to say that there would be no purpose in developing new materials unless due consideration were given to the load they exert on the global environment. The consumption of energy and other resources when a product is made, used, and returned should be minimized wherever possible.

Prior to receiving the Nobel Prize in chemistry in 2000 for my work in polymers, polymer science had been recognized three times. The first Nobel Prize in chemistry for polymer science was awarded in 1953 to Hermann Staudinger, for his pioneering work in the 1920s. At that time, the concept of macromolecules was new, and his ideas were controversial. However, the data prevailed, and he was awarded the Prize “for his discoveries in the field of macromolecular chemistry.” The next major event in polymer science was the discovery and invention of nylon by Wallace Carothers at the Dupont Company in 1935. Although Carothers died as a young man, his discoveries created an industry. I have little doubt that his work was deserving of a Nobel Prize and probably would have been awarded. The next related Prize went to Karl Ziegler and Giulio Natta in 1963 for their work on polymer synthesis in the 1950s. The Ziegler–Natta catalysts made possible the large-scale production of polymers such as polypropylene. They were awarded the Nobel Prize in chemistry “for their discoveries in the field of chemistry and technology of high polymers.” In 1974, the Prize for chemistry went to Paul J. Flory, who was a giant in this field. He was awarded the Nobel “for his fundamental achievements, both theoretical and experimental, in the physical chemistry of macromolecules.”