Carbon Atom Doped Pt Active Sites Enable Highly Active and Stable Catalytic Oxidation of Ethylene at Low Temperatures

Precisely tuning the surface properties of Pt active sites is of great importance for designing highly active catalysts used in the low-temperature catalytic oxidation of ethylene (C₂H₄). Herein, carbon doped Pt catalysts supported on SBA-15 (PtC<i>_<i>x</i></i>/SBA-15) were prepared by ethane (C₂H₆) heat treatment on SBA-15 supported Pt catalysts (Pt/SBA-15). Characterization results disclose that carbon atoms are successfully introduced in Pt particles, forming unique PtC<i>_<i>x</i></i> active sites. The PtC<i>_<i>x</i></i> active sites exhibit strong C₂H₄ adsorption and activation ability, enhanced hydrophobicity, and high catalytic activity for CO oxidation. As a result, PtC<i>_<i>x</i></i>/SBA-15 catalysts exhibit much higher C₂H₄ conversion and CO₂ yield than Pt/SBA-15 catalysts at 0 °C. Particularly, 3PtC<i>_<i>x</i></i>/SBA-15 maintains 100% conversion of 50 ppm of C₂H₄ for more than 7 h and even displays 93.2% C₂H₄ conversion and 88.8% CO₂ yield after 20 h of time-on-stream (TOS), exhibiting unprecedentedly prominent catalytic performance. This study provides a universal and efficient strategy to accurately enhance the surface hydrophobicity of noble metal particles employed in the low-temperature catalytic oxidation of C₂H₄. More importantly, it opens a new pathway for constructing highly active catalysts from the perspective of accelerating the oxidation of intermediate species to achieve improved utilization efficiency of active sites.