The Stability of Sulfur Stabilized Pt Single Atom Electroatalyst

Abstract

Single atom catalysts (SACs) are of great interest in recent scientific development because they possess the highest possible mass specific activity compared to conventional nanoparticle (NP) based catalysts. Therefore, the use of SACs is especially attractive for applications where noble metal catalysts are required. The enhanced mass activity can aid in reducing the metal loading, and thus the cost of these systems. Due to the reduction in metal loading, the stability of SACs is critical for ensuring their long-term electrochemical performance. In this study, the stability of high S content carbon supported Pt SACs was investigated by using electrochemcial accelerated stress tests (ASTs). The amounts of dissolved S and Pt were directly measured in relations to applied potentials. These dissolved ions were detected in-situ through the use of a scanning flow-cell (SFC) connected to an on-line inductively coupled plasma mass spectrometer (ICPMS). The morphological and elemental changes of the catalyst were also examined by identical location transmission electron microscopy and X-ray spectroscopy before and after the ASTs. The interactions between Pt SACs and S surface groups were probed by series of experimental designs. The results indicated that these S stabilized Pt SACs were significantly more stable when compared to their NP-based counterparts, and there exists a possible mutual interaction between S and Pt SACs.