2018 John Howard Appleton Lecture

Professor Harry Gray

The Department of Chemistry presents Professor Harry B. Gray as the 2018 John Howard Appleton Lecturer. Prof. Gray is the Arnold O. Beckman Professor of Chemistry at the California Institute of Technology and Founding Director of the Beckman Institute of CalTech. He has authored over 910 research papers and published 18 books throughout his career.

Prof. Gray will present the Appleton Lecture and a Chemistry Colloquium the following day. Please see the titles, abstracts, and additional information below.


APPLETON LECTURE —"Fuel from Sunlight and Water"

Thursday, April 5, 2018

Reception: 3:30 PM, MacMillan Hall Lobby
Seminar: 4:00 - 5:00 PM, MacMillan 117 (C.V. Starr Auditorium)
167 Thayer Street, Providence, RI

The efficient generation of molecular hydrogen from sunlight and water is one of the holy grails of 21st century chemistry. Hydrogen is a clean, renewable fuel that could play a key role in meeting the world’s skyrocketing demand for energy. Several investigators have employed hydrogenases as catalysts coupled to cathodes for H2 production, as these enzymes can operate in water with very high turnover frequencies. But these enzymes are not stable under aerobic conditions, so recent work has largely focused on robust inorganic materials. Among inorganic materials, platinum is a very active catalyst for proton reduction, but scarcity and high cost limit its widespread use. Clearly, we must replace platinum in solar-driven water splitting devices! The good news is that investigators in the NSF CCI Solar Fuels Program have accepted this challenge: working together, we have found that Ni–Mo nanopowders and metal phosphide nanocrystals have catalytic efficiencies near that of platinum for hydrogen evolution from water. We also have developed robust mixed-metal nanostructured catalysts for the production of oxygen from water. There is an urgent need to find even better water oxidation catalysts, as the protons and electrons liberated when oxygen is evolved are the fundamental particles required for sustainable energy storing reactions, not only for hydrogen production, but also for the conversion of nitrogen and carbon dioxide to fuels and chemicals.



CHEMISTRY COLLOQUIUM —"Living with Oxygen"

Friday, April 6, 2018

Reception: 3:30 PM, GeoChem 349
Seminar: 4:00 - 5:00 PM, MacMillan 115
167 Thayer Street, Providence, RI

High-valent iron-oxos are intermediates in biology reactions critical to life on Earth, notably including oxygen reduction to water by cytochrome oxidates and steroid oxygenation by cytochrome P450. Jay Winkler and I recently discovered that Oxygenases and other enzymes that require oxygen for function have chains of tryptophans and tyrosines that extend from active-site regions to protein surfaces. We think it likely that hole tunneling through these TRP/TYR chains protects redox enzymes from oxidative destruction.