UNDERSTANDING REACTION MECHANISMS AND CREATING NEW CHEMISTRIES IMPORTANT TO HEALTH, RENEWABLE ENERGY, MATERIALS, ENERGY AND ENVIRONMENTAL SCIENCE
The right catalyst can turn ordinary water – or even CO2 – into a clean-burning fuel; the wrong one will quickly degrade performance in solar-cell or electronics manufacturing. In biology, one key enzyme catalyzes the reduction of O2 to H2O in human respiration; another promotes the inflammatory response of celiac disease.
Stanford breakthroughs in catalysis advance understanding of reactions essential to industrial production, health and the environment. Ongoing efforts put this knowledge to work, harnessing catalysis to make chemical bonds in new ways and create new forms of matter. At the forefront of new approaches for generating and storing energy, Stanford chemists are developing strategies for extracting electrons from chemical fuels and injecting them into carbon dioxide as a means of storing chemical energy and creating new chemical intermediates from sunlight and carbon dioxide.
New catalytic processes can improve efficiency and reduce costs – both economic and environmental – of any chemical process. In principal, a catalyst aids transformation of its products while remaining unchanged itself, supporting indefinite reuse. In practice, secondary reactions gradually consume most industrial catalysts, making it important to avoid expensive agents. Promising new directions aim to reduce reaction steps and seek out catalysts based on readily available materials, for example, using metal oxide catalysts in place of those based on rare metals such as platinum and rhodium.
Stanford Chemistry faculty work with colleagues across campus, including the Global Climate and Energy Project and Stanford Precourt Institute for Energy, in catalysis research spanning several areas:
Mechanisms of Catalysis
Understanding reaction mechanisms is crucial to developing new catalysts and improving reaction yields. Stanford chemists pioneered the use of lasers to study chemical reactions at the molecular level, developing laser-induced fluorescence to study reaction dynamics and making seminal contributions to our understanding of molecular collision processes. Ongoing work investigates transition metal catalyzed C-H reactions using mass spectrometry. Pioneering studies based on Stark spectroscopy (spectroscopy in electric fields) have demonstrate the electrostatic contributions to enzyme activity, opening a new paradigm for understanding catalysis.
Stanford chemists are harnessing new insights into enzyme structure and mechanisms of action to improve human health, for example, studying and engineering enzymatic assembly lines that catalyze the biosynthesis of antibiotics in bacteria, and examining the role of transglutaminase 2 in celiac disease.
Inspired by the unsurpassed specificity and energy efficiency of metalloenzymes, Stanford studies are providing key insights into the mechanism of dioxygen activation in energy metabolism by copper-containing enzymes, with the aim of moving these efficient enzymatic mechanisms into small synthetic complexes on silica materials or carbon electrodes. New spectroscopic and theoretical techniques are advancing our understanding of the electronic and geometric structures of biologically- and catalytically-relevant transition metal sites, their contributions to reactivity, and structure/function relationships. Pioneering Stanford work in synthetic and mechanistic organometallic chemistry continues to invent new metal-catalyzed reactions. Powerful new approaches are pushing the boundaries of modern organic synthesis and enabling the design and synthesis of exotic small and giant molecules for custom properties.
Ongoing research into metal oxide catalysts explores efficient means to convert plain water, nitrogen gas or carbon dioxide into clean-burning hydrogen fuel, without expensive catalysts based on rare metals. Stanford chemists are investigating “defect-rich” heterogeneous electro-catalysts for converting carbon dioxide and carbon monoxide to liquid fuel. Exploration of new chemistries has also led to development of a cost-efficient water splitting catalyst for renewable production of hydrogen fuel based on inexpensive nickel–iron chemistry, as well as groundbreaking aluminum-based battery technology.
In addition to opening new energy sources, research into catalytic mechanisms and materials can improve industrial efficiency, produce greener materials, and further understanding of environmental impacts. For example, the key to achieving the 'ideal synthesis' and greener chemistry, step economy relies on discovery or invention of new reactions, which may in turn be made possible with novel catalysts. Inovations in synthetic processes include efficient methods to create new chemist’s enzymes – transition-metal-based non-protein catalysts that enable key reactions. Stanford studies pursuing new catalysts and chemical reactions recently developed a novel method to create plastic from carbon dioxide and inedible plant material rather than petroleum products. New organometallic and organic catalysts have enabled the synthesis of complex macromolecular architectures including sustainable polymers, synthetic fuels and bioactive molecules. This work has opened a new path for production of environmentally sustainable plastics, earning recognition in the 2012 Presidential Green Chemistry Award. Improving our understanding of environmental impacts, Stanford research into the interaction of ultraviolet radiation with chlorofluorocarbons (CFCs) led to discovery of CFCs' role in catalyzing breakdown of the Earth's ozone layer.