(66g) Improving the Efficiency of Electrocatalytic Ozone Production with Catalyst Microstructure and Dopants

The need to provide clean drinking water to a growing population is well-recognized as a major engineering challenge for the 21^st century. Ozone is a powerful disinfectant with many advantageous properties, but the existing methods of production are energy-intensive and require bulky, expensive equipment. Electrochemical ozone production could greatly reduce the operating and capital expense required, but existing catalyst materials do not have adequate performance. In this work, we discuss approaches to improve the activity and selectivity for electrocatalytic ozone production, and how such approaches can shed light on the fundamental reaction mechanism. In one example, we develop an electrodeposition technique to synthesize nanostructured Ni-Sb-SnO2 electrocatalysts with improved activity and selectivity for the EOP reaction over existing materials¹. The optimal temperature of the post-deposition oxidation treatment is determined by the tradeoff between catalyst stability and crystallinity. In another study, we have identified new combinations of transition- and rare-earth-metal dopants that increase ozone selectivity up to 75%². Analyzing the effect of catalyst loading indicates that the reaction is mediated by a solution-phase intermediate, while selective radical quenching experiments suggest that peroxo species play a key role in the mechanism. The identity of radical intermediates is corroborated by first-principles calculations of acid-base pKas for hypothesized intermediates. Efforts to identify the origin of this improved performance using spectroscopic and other methods are ongoing.