Preparation of doped perovskite catalysts and their catalytic performance for direct conversion of syngas to C2+ alcohols
Direct conversion of syngas to C2+ alcohols(alcohols with two or more carbon atoms)is currently one of the most promising routes for the synthesis of alcohols,and perovskite-structured catalysts can be used to improve the performance for the synthesis of C2+ alcohols in this process.Co and Mn doped perovskite LFC and LFM catalysts(L,F,C and M refer to metal La,Fe,Co and Mn,respectively)were prepared by co-precipitation method,respectively,and the effects of different calcination temperatures and doped elements on the catalytic performance of perovskite catalysts were systematically investigated in C2+ alcohols synthesis.Results of various characterizations show that the low calcination temperature can optimize the structural properties and adsorption behaviors of LF-600(the numbers after"-"refer to the calcination temperature)catalyst,and the coupling of CO dissociation and non-dissociation sites on LF-600 catalyst helps to increase CO conversion and total alcohol selectivity to 16.9%and 31.2%(mass fraction),respectively.The doping of Co and Mn can change the product distribution and activity of LF-600 catalyst.Compared with LF-600 catalyst,LFC-600 catalyst promotes the chain growth due to the low H2 adsorption capacity,thereby increasing the proportion of C2+ alcohols in total alcohols from 60.4%to 71.6%.LFM-600 catalyst has more low-temperature H2 adsorption sites leading to methanol being the main alcohol product,while particle agglomeration and Mn and O aggregation caused by Mn doping can reduce the activity of LFM-600 catalyst.
syngasC2+ alcoholsperovskite catalystsB-site dopingcalcination temperature
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