Fe₅C₂ Nanoparticles: A Facile Bromide-Induced Synthesis and as an Active Phase for Fischer–Tropsch Synthesis

Abstract

Iron carbide nanoparticles have long been considered to have great potential in new energy conversion, nanomagnets, and nanomedicines. However, the conventional relatively harsh synthetic conditions of iron carbide hindered its wide applications. In this article, we present a facile wet-chemical route for the synthesis of Hägg iron carbide (Fe(5)C(2)) nanoparticles, in which bromide was found to be the key inducing agent for the conversion of Fe(CO)(5) to Fe(5)C(2) in the synthetic process. Furthermore, the as-synthesized Fe(5)C(2) nanoparticles were applied in the Fischer-Tropsch synthesis (FTS) and exhibited intrinsic catalytic activity in FTS, demonstrating that Fe(5)C(2) is an active phase for FTS. Compared with a conventional reduced-hematite catalyst, the Fe(5)C(2) nanoparticles showed enhanced catalytic performance in terms of CO conversion and product selectivity.

Variable Temperature 57Fe-Mössbauer Spectroscopy Study of Nanoparticle Iron Carbides

“…[9] The nanoparticles of Hägg carbide, Fe5C2, were prepared by decomposition of iron pentacarbonyl in the presence of hexadecyltrimethylammonium bromide (CTAB) at 350 °C. [10] The details of the synthesis procedures may be found in the relevant sources provided.…”

ε-Iron carbide as a low-temperature Fischer–Tropsch synthesis catalyst

“…At typical FTS temperature of 543 K, many reports agree that the active phase is w-Fe 5 C 2 , while y-Fe 3 C is a spectator or a deactivation phase 10,19,[21][22][23] . Pure w-Fe 5 C 2 nanoparticles (NPs) have been synthesized and supported, and proven to be better than a reduced haematite catalyst in terms of CO conversion and product selectivity 24 . In contrast, O-carbides are favoured in high carbon potential (m c ) surroundings, that is, low temperature (o473 K) and high CO partial pressure, with m c more sensitive to temperature than to pressure 25 .…”

Influence of precursor porosity on sodium and sulfur promoted iron/carbon Fischer–Tropsch catalysts derived from metal–organic frameworks

“…3 In particular, carbon materials are attractive as supports due to their moderate interaction with iron oxide and hence rapid carbide formation after exposure to synthesis gas. 7,11,12 Furthermore, carbonaceous supports stand out due to high chemical stability, high surface area, variable pore structure, and versatile surface chemistry. [13][14][15] The most widely applied method for the preparation of carbon-supported FTO catalysts is deposition of the iron precursor (most often by solution impregnation) on the surface of a pre-formed carbon material (e.g., carbon nanotubes, porous carbons, or carbon nanofibers) followed by drying and calcination.…”