Graphene-supported iron phosphide nanoparticles for fischer-tropsch synthesis

Abstract

Graphene (G) is a huge open π-electron system with a unique electronic structure, which ignites diverse applications such as electronics, photovoltaics, batteries, supercapacitors and so on. Because of the larger surface area, G can be used as the catalyst or the advantageous carrier for the catalytic active components for hydrogenation, oxidation and carbon-carbon coupling reactions. In the present study, we exploited G as a support for iron phosphide nanoparticles (FeP/G) by calcination the precursor iron phosphate-graphene oxide nanocomposite (FePO/GO) under hydrogen atmosphere. In the same method, we also prepared the control pure iron phosphide (FeP) by H2 calcination the precursor iron phosphate (FePO). The FePO of FePO/GO existed in the form of porous spherical and the particle size ranges from 100 nm to 300 nm. After transforming into FeP, the average particle size of FeP is about 10 nm while the particles were uniformly dispersed on the G and no obvious aggregation was observed. While, not only the pure FePO but also the pure FeP was powerful aggregation. That meant GO and G could regulate the microstructure and morphology of FePO and FeP, respectively. The as-prepared products were investigated by X-ray diffraction, transmission electron microscopy, field emission environment scanning electron microscopy and XPS spectroscopy. XPS spectra showed that the electron binding energy of Fe in FeP/G increased slightly. The Fischer-Tropsch Synthesis (FTS) reaction has been selected as model reaction for evaluating FeP/G. When the reaction conditions were 15 mg catalyst (reduced in H2 at 623 K for 2 h prior to FTS reaction), 2 MPa syngas (CO:H2:Ar=32:63:5), 5 mL·min-1, 593 K, the remarkable catalytic discrepancies in FTS activity and product selectivity were observed. The activity toward the conversion of CO on FeP/G was about 70 times that of FeP. The result show that FeP/G catalysts are potential good catalysts for FTS. © 2013 Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences.