Scientists introduce a new catalyst to reduce oxygen to widely used hydrogen peroxide. The process sidesteps complex and expensive processes that generate toxic organic byproducts and large amounts of wastewater.
Rice scientists treated metal-free carbon black, the inexpensive, powdered product of petroleum production, with oxygen plasma. The process introduces defects and oxygen-containing groups into the structure of the carbon particles, exposing more surface area for interactions.
When used as a catalyst, the defective particles known as CB-Plasma reduce oxygen to hydrogen peroxide with 100% Faradaic efficiency, a measure of charge transfer in electrochemical reactions. The process shows promise to replace the complex anthraquinone-based production method that requires expensive catalysts and generates toxic organic byproducts and large amounts of wastewater, according to the researchers.
The research by Rice chemist James Tour and materials theorist Boris Yakobson appears in the American Chemical Society journal ACS Catalysis.
Hydrogen peroxide is widely used as a disinfectant, as well as in wastewater treatment, in the paper and pulp industries and for chemical oxidation. Tour expects the new process will influence the design of hydrogen peroxide catalysts going forward.
«The electrochemical process outlined here needs no metal catalysts, and this will lower the cost and make the entire process far simpler,» Tour said. «Proper engineering of carbon structure could provide suitable active sites that reduce oxygen molecules while maintaining the O-O bond, so that hydrogen peroxide is the only product. Besides that, the metal-free design helps prevent the decomposition of hydrogen peroxide.»
Plasma processing creates defects in carbon black particles that appear as five- or seven-member rings in the material’s atomic lattice. The process sometimes removes enough atoms to create vacancies in the lattice.
Story Source: Materials provided by Rice University. Note: Content may be edited for style and length.