Piezoelectric Electric Supports Modulate the Reactivity of Platinum Thin Films

Abstract

The oxygen reduction reaction (ORR) is at the heart of many renewable energy technologies. This kinetically slow reaction requires large overpotentials even on the best catalysts like platinum and its alloys. Numerous studies have employed strained platinum surfaces to change oxygen adsorbate binding energies and lower the ORR overpotential, though strain is often convoluted with electronic effects from alloying with other metals. Additionally, discrete samples offer only one static strain condition, making testing of multiple surface configurations costly. We present a piezoelectric platform capable of generating dynamic strain on thin film platinum catalysts without unwanted electronic effects due to alloying. Application of various voltages to an interdigitated array on the piezoelectric drives the mechanical deformation of the platinum thin film, resulting in significant increases in ORR activity and up to 10 mV lower overpotentials. The applied mechanical strain is reversible, and reactivity changes are not resultant from electronic communication between the piezoelectric and electrode, temperature increases, or local field effects. This new analytical platform opens new opportunities for studying strain effects in electrocatalysis.