The active pairs of Co-Co2C adjusted by La-doped CaTiO3 with perovskite phase for higher alcohol synthesis from syngas

Abstract

Catalytic conversion of syngas (CO + H2) to higher alcohols is desirable, but a high C2+OH selectivity is challenging to achieve due to the difficult equilibrium between dissociatively adsorbed CO and non-dissociatively adsorbed CO. In this work, Ca1-xLaxTi1-xCoxO3 catalysts are facilely prepared by using citrate complexing method, and a part of metal Co is transformed to Co2C during reaction. In the process of reaction, the synergistic effects among metal Co, Co2C and oxygen vacancies boost the conversion of syngas to higher alcohols. Metal Co nanoparticles are used to promote the dissociative adsorption CO and C–C coupling, subsequently combine with *CO adsorbed on Co2C to produce alcohols. Besides, oxygen vacancy can be used to activate oxygen-containing compounds and enhance higher alcohols synthesis. The surface Co2C/Co ratio has significant influences on catalytic activity and stability of catalysts, which can be adjusted by the Co/Ti ratio. The C0.7L0.3T0.7C0.3O3 catalyst exhibits the highest selectivity of higher alcohols due to the moderate surface Co2C/Co ratio, which has an appropriate balance between *C, *CO and C–C coupling.