Insight into the role of lanthanum-modified Cu[sbnd]Co based catalyst for higher alcohol synthesis from syngas

Abstract

A series of lanthanum oxide modified CuCo based catalysts for the direct conversion of syngas to higher alcohols were synthesized via the coprecipitation method. The influence of lanthanum on the textural properties and catalytic performance was investigated. It was found that lanthanum-modified CuCo based catalysts possessed a novel nanosheet structure to form more oxygen vacancies. Compared with CuCo catalyst, the dissociative CO adsorption and associative CO adsorption capacities of LaxCuCo catalysts were improved markedly, and formate and methoxy intermediates were more easily formed on the surface of LaxCuCo catalysts, which is attributed to the proper synergy of the surface active sites (Cu0, Co0, and oxygen vacancies). In particular, the addition of lanthanum species reduced the thickness of the nanosheets and facilitated the high dispersion of LaxCuCo after reaction by acting as isolation islands to restrain the aggregation and growth of crystal grain. The evaluation results showed that optimized La0.3CuCo catalyst exhibited the highest CO conversion of 25.4%, superior total alcohols selectivity of 61.4%, and C2+ alcohols selectivity of 79.03% among the total alcohol products, and excellent stability.