Regulating the location of metal promoters in CuFe-based catalysts for enhanced CO2 hydrogenation to higher alcohols

Abstract

Regulating the location of the metal promoters plays a vital role in catalyst structure and its catalytic behavior during CO₂ hydrogenation to higher alcohols. Herein, we selected the metal promoters with a precipitation pH similar to that of Cu²⁺ or Fe³⁺ to prepare a series of CuFe-based catalysts. Characterization results show that doping Al or Cr promoter, located with the Fe phase, suppressed the excessive carburization of the Fe phase and maintained an optimal proportion between Fe₃O₄ and amorphous iron carbide (FeC_x), thus exhibiting superior catalytic activity and stability. In contrast, doping Zn or In promoter, located with the Cu phase, underwent a deeper carburization and formed more crystalline FeC_x, showing an inferior performance. The CuFeCr catalyst achieved the highest space-time yield of 330 mg $g_{cat}^{-1}$ h⁻¹ for higher alcohols among these catalysts. This study provides a novel strategy for optimizing the structure of the active phases for CO₂ hydrogenation.