Effect of Precursors of Fe-Based Fischer–Tropsch Catalysts Supported on Expanded Graphite for CO<sub>2</sub> Hydrogenation
Rui Zhao, Xin Meng, Qiangfeng Yin, Wenli Gao, Wenhua Dai, Daoming Jin, Bowen Xu, Zhong Xin
Abstract
Expanded graphite as a type of hydrophobic functional carbon material was innovatively selected as support for Fe-based Fischer–Tropsch catalysts. Through catalytic activity evaluation, ferric ammonium citrate was selected as the most suitable iron precursor for expanded graphite among ferric nitrate, ferric ammonium oxalate, ferric citrate, and ferric ammonium citrate. The catalyst with ferric ammonium citrate as the precursor and expanded graphite as support achieved the best CO2 hydrogenation performance with a CO2 conversion rate of 42.4%, a C2═–C4═ yield of 14.8%, and a CO selectivity of 8.3%. Furthermore, it was observed that the precursor that had better wettability and formed hydrogen bonds with support tended to generate smaller iron nanoparticles. In addition, nitrogen doping during catalyst calcination would cause differences in electronic properties and then influence the reducibility and carbonization of iron species.