Structure and activity of strontium substituted LaCoO3 perovskite catalysts for syngas conversion

• Role of strontium in Fischer–Tropsch catalysts reported for the first time.
• Strontium substitution level has an inverse effect on Fischer–Tropsch synthesis.
• Structural transformation has effects on catalyst reducibility and Co0 sintering.
• The highest reaction activity was obtained at catalyst La/Sr = 0.1.

Study of the catalytic activity of LaCoO3 perovskite catalysts with varying degrees of strontium substitution (La1-xSrxCoO3) in the Fischer–Tropsch synthesis is presented for the first time in this paper. It was found that Sr substitution improves the catalyst’s reducibility and increasing strontium substitution beyond a threshold of 10 mol% Sr has an inverse effect on the catalytic performance in the syngas conversion. For x ≤ 0.1, the catalysts exhibited a stable rhombohedral structure, which leads to well dispersion of active centre Co0 during the reduction process and displayed a high catalytic activity. For x ≥ 0.2 the catalyst structure was gradually changed, from a rhombohedral to a less stable cubic structure, and leads to Co0 sintering. The turnover frequency of Co atom in the Fischer–Tropsch reaction decreased significantly with increasing strontium substitution levels due to the loss of active catalyst surface. The La0.9Sr0.1CoO3 catalyst showed the highest catalytic activity in the Fischer–Tropsch synthesis.

Figure optionsDownload high-quality image (173 K)Download as PowerPoint slide