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.

The widespread application of polymer electrolyte membrane water electrolyzers (PEMWEs) remains a tough challenge to date, as they rely on the use of highly scarce iridium (Ir) with insufficient catalytic performance for the oxygen evolution reaction (OER). Therefore, exploring the degradation and activation mechanism of Ir-based catalysts during the OER and searching for highly efficient Ir-based catalysts are essential to achieve large-scale hydrogen production with PEMWEs. This minireview briefly describes the adsorbate evolution mechanism and lattice oxygen oxidation mechanism for Ir-based catalysts to complete the OER process. Then, the valence change of Ir during the OER is discussed to illustrate the origin of the favorable stability of Ir-based catalysts. After that, different modification strategies for IrO₂, such as elemental doping, surface engineering, atom utilization enhancing, and support engineering, are summarized in the hopes of finding some commonalities for improving performance. Finally, the perspectives for the development of Ir-based OER catalysts in PEMWEs are presented.