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 (PtCx/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 PtCx active sites. The PtCx active sites exhibit strong C2H4 adsorption and activation ability, enhanced hydrophobicity, and high catalytic activity for CO oxidation. As a result, PtCx/SBA-15 catalysts exhibit much higher C2H4 conversion and CO2 yield than Pt/SBA-15 catalysts at 0 °C. Particularly, 3PtCx/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.