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<p>We demonstrate a calcine-and-use, Mn-promoted Co/γ-Al<sub>2</sub>O<sub>3</sub> prepared by single-pot citrate–nitrate auto-combustion that performs in Fischer–Tropsch synthesis without the conventional 600&#xa0;°C H<sub>2</sub> pre-reduction. Compared with a wet-impregnated benchmark (WI), the auto-combustion sample (SC) forms ~ 10&#xa0;nm Co domains on a 108 m<sup>2</sup>&#xa0;g<sup>−1</sup> matrix (vs ~ 44&#xa0;nm on 73 m<sup>2</sup>&#xa0;g<sup>−1</sup> for WI), and H<sub>2</sub>-TPR confirms &gt; 90% reducibility below 510&#xa0;°C, whereas a spinel-bound fraction in WI persists up to 650&#xa0;°C. Under identical FT conditions (240&#xa0;°C, 10&#xa0;bar, H<sub>2</sub>/CO = 2, GHSV ≈ 3600&#xa0;h<sup>−1</sup>), SC converts 40.7% of CO (WI: 24.2%). At steady state (12–50&#xa0;h TOS; n = 3), selectivities were: SC CH<sub>4</sub> 30.3%, C<sub>5</sub><sup>+</sup> 45.6% (STYC<sub>5</sub><sup>+</sup> 1.66&#xa0;g&#xa0;h<sup>−1</sup> g_cat<sup>−1</sup>); WI CH<sub>4</sub> 19.8%, C<sub>5</sub><sup>+</sup> 62.3% (1.35). Carbon balances closed to 98 ± 2%. The activity gain is attributed to an ≈ 4 × larger surface cobalt inventory associated with ~ 10&#xa0;nm domains. Eliminating high-temperature pre-reduction simplifies operation and reduces thermal input, providing a ready-to-use Co/Al<sub>2</sub>O<sub>3</sub> route; stability and scale-up are identified as next steps.</p> Graphical abstract <p></p>

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Manganese-promoted nanostructured metallic Co/Al2O3 catalysts prepared using auto-combustion procedure without further reduction for Fischer–Tropsch synthesis

  • 期刊论文

  • 发表日期：

    2025年10月17日

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  • Khaled Rasoulzadeh,
  • Ali Akbar Mirzaei,
  • Ebrahim Mollashahi

摘要

We demonstrate a calcine-and-use, Mn-promoted Co/γ-Al2O3 prepared by single-pot citrate–nitrate auto-combustion that performs in Fischer–Tropsch synthesis without the conventional 600 °C H2 pre-reduction. Compared with a wet-impregnated benchmark (WI), the auto-combustion sample (SC) forms ~ 10 nm Co domains on a 108 m2 g−1 matrix (vs ~ 44 nm on 73 m2 g−1 for WI), and H2-TPR confirms > 90% reducibility below 510 °C, whereas a spinel-bound fraction in WI persists up to 650 °C. Under identical FT conditions (240 °C, 10 bar, H2/CO = 2, GHSV ≈ 3600 h−1), SC converts 40.7% of CO (WI: 24.2%). At steady state (12–50 h TOS; n = 3), selectivities were: SC CH4 30.3%, C5+ 45.6% (STYC5+ 1.66 g h−1 g_cat−1); WI CH4 19.8%, C5+ 62.3% (1.35). Carbon balances closed to 98 ± 2%. The activity gain is attributed to an ≈ 4 × larger surface cobalt inventory associated with ~ 10 nm domains. Eliminating high-temperature pre-reduction simplifies operation and reduces thermal input, providing a ready-to-use Co/Al2O3 route; stability and scale-up are identified as next steps.

Graphical abstract