We describe a conceptual framework for engineering photoelectrochemical systems specifically for nitrate reduction in water. This framework is developed on the basis of results obtained in our laboratory and of that found in the literature. Nitrate reduction to dinitrogen at neutral pH without the addition of an electron donor has a large kinetic barrier requiring step-wise multi-proton coupled electron transfers. Achieving this over a single photocatalyst is not efficient due to hole competition between water oxidation and the nitrite back-reaction to nitrate. Overcoming these challenges will require more advanced materials that hinge on a better understanding of the atomic-scale mechanisms. Design strategies such as ideal photocatalysts, co-catalyst choice, semiconductor heterojunctions, and electrode material selection for nitrate reduction are discussed, as well as the implications of this framework for similar drinking water pollutants (e.g., oxo-anions).

Framework for developing photocatalysts for nitrate reduction in water

246th National Meeting (2013)

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