Paper-structured catalysts with porous fiber networks for fischer-tropsch synthesis

The Fischer-Tropsch synthesis (FTS) is a promising catalytic process for converting syngas (hydrogen and carbon monoxide (CO)) into valuable hydrocarbons for use as fuels and fine chemicals. However, the FTS reaction is highly exothermic; hence careful process control is required to promote smooth gas flow and avoid the formation of local hot spots inside the catalyst layer. In this work, cobalt (Co)-based paper-structured catalysts with micrometer-size pores were prepared via a papermaking technique and an impregnation method. The FTS reaction was carried out using Co-containing paper composites having different Co loadings, residence times and stacking patterns to investigate the effects of the catalyst layer design on the FTS catalytic efficiency. Catalyti-cally-active metallic Co nanoparticles were successfully synthesized inside the porous fiber networks of the flexible and easy-to-handle paper composites. An alternate stacking arrangement of five Co papers and a designated number of catalyst-free ceramic papers demonstrated higher CO conversion than stacks of the Co papers alone without ceramic spacing layers, despite the same total Co loading and gas residence time inside the catalyst layers. It was assumed that the catalyst-free ceramic papers with porous fiber networks effectively promoted the diffusion of both gas and heat during the exothermic FTS processes. Our paper-structured catalysts with a unique porous architecture allowed fine-tuning of the catalyst layers by stacking the various paper composites. These results are expected to advance catalytic FTS process engineering.