With a dash of water and sunlight, researchers turn propane into propylene using copper single-atom catalyst

Propane dehydrogenation (PDH) reaction is a highly endothermic reaction, typically requiring temperatures above 600°C in conventional thermo-catalysis. However, elevated temperatures lead to significant energy consumption, catalyst sintering, and coke deposition. Overcoming these thermodynamic and kinetic challenges to achieve propane dehydrogenation under ambient conditions remains a major goal in catalysis.

In a study published in Nature Chemistry, a team led by Prof. Zhang Tao and Prof. Wang Aiqin from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences (CAS), collaborating with Prof. Gao Yi’s team from the Shanghai Advanced Research Institute of CAS, developed a water-catalyzed PDH reaction route using a copper single-atom catalyst (SAC) through photo-thermo catalysis, enabling highly efficient propane-to-propylene conversion under mild conditions.

By using a Cu₁/TiO₂ SAC, researchers achieved PDH under near-ambient conditions in a water vapor atmosphere. In a continuous-flow fixed-bed reactor, the reaction temperature was reduced to just 50–80 °C, achieving a maximum reaction rate of 1201 μmol g_cat^-1 h^-1.

Researchers revealed that Cu single atoms, water vapor, and light illumination all played essential roles in the propane-to-propylene conversion.

Through photocatalytic water splitting on the Cu₁/TiO₂ SAC, hydrogen and hydroxyl species were generated. Hydroxyl radicals subsequently adsorbed on the catalyst surface, abstracting hydrogen atoms from propane to form propylene and water. Water acted catalytically without being consumed. This mechanism fundamentally differs from traditional PDH and oxidative dehydrogenation of propane.

Furthermore, researchers demonstrated that the developed route could be extended to the dehydrogenation of other light alkanes, including ethane and butane. The reaction could even be directly driven by sunlight using the Cu₁/TiO₂ SAC.

“Our study not only provides a new way for PDH but also establishes a paradigm for conducting high-temperature reactions driven by solar energy,” said Prof. Liu Xiaoyan, one corresponding author of the study.