Synergistic effects of acid-base and electronic properties upon second metals-modified Ga₂O₃/Silicalite-1 catalysts for efficient CO₂-assisted propane dehydrogenation

Ga-based catalysts exhibit significant potential in activating C[sbnd]H bonds and enhancing the catalytic efficiency during CO₂-assisted propane dehydrogenation (CO₂-ODP). However, achieving high C₃H₆ selectivity remains challenging due to severe side reactions caused by their strong acid strength. In this work, second metal promoters (Cu, Co, Zn, Sn and Fe) are incorporated into Ga₂O₃/Silicalite-1 catalysts, respectively, effectively enhancing the interaction between Ga species and S-1 support by facilitating the electron transport, thereby improving the dispersity of Ga₂O₃ sites. Notably, the introduction of Cu into Ga₂O₃/S-1 catalyst (7Ga₂O₃-0.5Cu/S-1) not only modulates the acid-base balance to promote C₃H₆ desorption, but also enhances CO₂ activation by generating more strongly basic sites. As a result, the 7Ga₂O₃-0.5Cu/S-1 catalyst achieves initial C₃H₆ yield and CO₂ conversion of 52.7 % and 29.7 %, respectively, maintaining at 37.7 % and 19.7 % after 8 h of catalysis. These results surpass most reported Ga-based catalysts and even non-precious-metal-based catalysts over the past five years. The second metal modification strategy provides valuable insights into the synergistic modulation of acid-base balance and electronic interactions.