Electrochemical-Method-Induced Strong Metal-Support Interaction in Pt-CNT@SnO₂ for CO-Tolerant Hydrogen Oxidation Reaction

Inducing the classic strong metal-support interaction (SMSI) is an effective approach to enhance the performance of supported metal catalysts by encapsulating the metal nanoparticles (NPs) with supports. Conventional thermal reduction method for inducing SMSI processes is often accompanied by undesirable structural evolution of metal NPs. In this study, a mild electrochemical method has been developed as a new approach to induce SMSI, using the cable structured core@shell CNT@SnO₂ loaded Pt NPs as a proof of concept. The induced SnO_x encapsulation layer on the surface of Pt NPs can protect Pt NPs from the poisoned of CO impurity in hydrogen oxidation reaction (HOR), and the HOR current density could still maintain 85% for 2000 s with 10,000 ppm CO in H₂, while the commercial Pt/C is completely inactivated. In addition, the electrons transfer from SnO_x to Pt NPs improved the HOR activity of the E-Pt-CNT@SnO₂, achieving the excellent exchange current density of 1.55 A·mg_Pt^—1. In situ Raman spectra and theoretical calculations show that the key to the electrochemical-method-induced SMSI is the formation of defects and the migration of SnO_x caused by the electrochemical redox operation, and the weakening the Sn—O bond strength by Pt NPs.