Surface reconstruction enhancing activity of Pt/C for formic acid electrooxidation by ultrasonic mixing with Pb/C and electrochemical activation process

Abstract

The control for surface of catalysts is intrinsically required to improve catalytic efficiency. In current work, we demonstrate that the surface of Pt/C catalyst can be effectively reconstructed by ultrasonic mixing with Pb/C in an acidic environment and electorchemical activation process. As a result, the surface-reconstructed Pt/C catalyst exhibits a significant enhancement of activity of a ca. 10-fold improvement in mass activity and a ca. 38-fold improvement in specific activity as compared with a pure Pt/C catalyst for formic acid electroxidation (FAEO). The evidences show that some of Pb species are transferred from Pb/C to surface of Pt/C catalyst probably through the dissolution–adsorption pathway during ultrasonic mixing and electorchemical activation processes. The presence of Pb on surface of Pt not only isolates the continuous Pt sites through the third-body effect but also modifies electronic band structure of platinum via electronic effect, which leads to that the direct pathway is preferably occurred and the CO formation is effectively inhibited. These results provide useful information for further understanding the promotion mechanism of Pb ad-atom during FAEO and rationally controlling the catalytic surface to improve catalytic efficiency.