High activity nitrogen-doped hollow carbon/silicon hollow spheres as encapsulated Pd–Fe nanoreactors for acetylene dialkoxycarbonylation

Abstract

Reducing the utilization of precious metals and minimizing their depletion has been a pivotal concern in precious metal catalyst research. Hence, we employed a wet impregnation method to fabricate hollow carbon and silicon nanospheres (PdFe/N_xC@mSiO₂), encapsulating PdFe bimetallic nanoparticles. These bimetallic nanoparticles were enclosed within the hollow spheres, forming an alloy facilitated by nitrogen anchoring. The Pd₄Fe₁/N_xC@mSiO₂ catalyst exhibited enhanced dispersion of Pd, strengthened metal-carrier interaction, and superior ability for CO adsorption enrichment compared to single Pd catalysts. In situ DRIFTS analysis further revealed that the PdFe alloy catalysts, prepared via Fe doping, exerted reduced force on CO and improved CO insertion efficiency. Consequently, the Pd₄Fe₁/N_xC@mSiO₂ catalyst demonstrated heightened catalytic activity. In comparison to the individual Pd catalyst, this catalyst showed exceptional catalytic activity in the acetylene dialkoxycarbonylation process, with strong selectivity for 1,4-dicarboxylate (>85%) and considerable acetylene conversion (>90%). Moreover, this catalyst displayed remarkable recyclability, remaining active even after five cycles.