Scientists develop a new catalyst to split water

Scientists develop a new catalyst to split water

First step to convert solar and wind power to renewable fuels

Toronto, Canada (ISJ) ? A team of international scientists have developed a catalyst to split water into hydrogen and oxygen, the vital first step to make fuels from renewable solar and wind power. The team has designed the most efficient catalyst for storing energy in chemical form, by splitting water into hydrogen and oxygen, just like plants do during photosynthesis. Oxygen is released harmlessly into the atmosphere, and hydrogen, as H2, can be converted back into energy using hydrogen fuel cells.

?Today on a solar farm or a wind farm, storage is typically provided with batteries. But batteries are expensive, and can typically only store a fixed amount of energy,? said Edward H. Sargent, a professor of electrical and computer engineering at the University of Toronto and the team leader. ?That?s why discovering a more efficient and highly scalable means of storing energy generated by renewables is one of the grand challenges in this field.?

Currently, water is split into its component elements - hydrogen and oxygen, by running electricity through it. This requires so much electrical input that it?s impractical to store energy? too great proportion of the energy generated is lost in the process of storing it.

This new catalyst facilitates the oxygen-evolution portion of the chemical reaction, making the conversion from H2O into O2 and H2 more energy-efficient than ever before. The intrinsic efficiency of the new catalyst material is over three times more efficient than the best state-of-the-art catalyst.

The new catalyst is made of abundant and low-cost metals tungsten, iron and cobalt, which are much less expensive than state-of-the-art catalysts based on precious metals. It showed no signs of degradation over more than 500 hours of continuous activity, unlike other efficient but short-lived catalysts. Their work was published in the leading journal Science.

?With the aid of theoretical predictions, we became convinced that including tungsten could lead to a better oxygen-evolving catalyst. Unfortunately, prior work did not show how to mix tungsten homogeneously with the active metals such as iron and cobalt,? says one of the study's lead authors, Dr. Bo Zhang.� ?We invented a new way to distribute the catalyst homogenously in a gel, and as a result built a device that works incredibly efficiently and robustly.?

This research was the collaborative effort of engineers, chemists, materials scientists, mathematicians, physicists, and computer scientists across three countries ? Stanford University, East China University of Science & Technology and University of Toronto.

?The team developed a new materials synthesis strategy to mix multiple metals homogeneously ? thereby overcoming the propensity of multi-metal mixtures to separate into distinct phases,? said Jeffrey C. Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems at Massachusetts Institute of Technology. ?This work impressively highlights the power of tightly coupled computational materials science with advanced experimental techniques, and sets a high bar for such a combined approach. It opens new avenues to speed progress in efficient materials for energy conversion and storage.?

?This work demonstrates the utility of using theory to guide the development of improved water-oxidation catalysts for further advances in the field of solar fuels," said Gary Brudvig, a professor in the Department of Chemistry at Yale University and director of the Yale Energy Sciences Institute.

Source: University of Toronto

Image courtesy: University of Toronto

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