New Approach to Fully Ordered fct-FePt Nanoparticles for Much Enhanced Electrocatalysis in Acid

Abstract

Fully ordered face-centered tetragonal (fct) FePt nanoparticles (NPs) are synthesized by thermal annealing of the MgO-coated dumbbell-like FePt-Fe3O4 NPs followed by acid washing to remove MgO. These fct-FePt NPs show strong ferromagnetism with room temperature coercivity reaching 33 kOe. They serve as a robust electrocatalyst for the oxygen reduction reaction (ORR) in 0.1 M HClO4 and hydrogen evolution reaction (HER) in 0.5 M H2SO4 with much enhanced activity (the most active fct-structured alloy NP catalyst ever reported) and stability (no obvious Fe loss and NP degradation after 20 000 cycles between 0.6 and 1.0 V (vs RHE)). Our work demonstrates a reliable approach to FePt NPs with much improved fct-ordering and catalytic efficiency for ORR and HER.

Patterning of L10FePt nanoparticles with ultra-high coercivity for bit-patterned media

“…As compared to the FePt NPs prepared from the similar methods reported in the literature, the coercivity in the present study was significantly increased from 1.4 T to 3.6 T, 10,41,42 which is even larger than the value (3.3 T) reported by Sun et al. 45 To our knowledge, this value represents the largest magnetic coercivity value for L10-FePt NPs ever reported. We believe that the main difference lies in the fact that the fct FePt NPs herein were synthesized under an Ar/H2 atmosphere, where the H2 could be adsorbed on the surface of the seeds of NPs during nucleation to hinder seed aggregation and further promote the growth on the seed surface.…”

Organic Phase Syntheses of Magnetic Nanoparticles and Their Applications

“…These L1 0 -FePt NPs are not only magnetically hard but also chemically robust for magnetic and catalytic applications. 168,192 3.2.6. FePd Nanoparticles.…”

“…A more convenient approach to protect the FePt NPs against high temperature aggregation/sintering was to coat the A1-FePt NPs with a robust shell such as SiO 2 187,188 or MgO. 189,192 The FePt NPs might also be doped with a third element, such as Au, 164 Ag, 165 or Cu, 386 to lower the phase transformation temperature.…”

Platinum-nickel alloy excavated nano-multipods with hexagonal close-packed structure and superior activity towards hydrogen evolution reaction

“…Although allomorphs of noble metal-based nanocrystals (NCs) have shown fascinating properties in optics, magnetism and catalysis, their crystal phase regulations are extremely difficult456. So far, only a few meta-stable phases of noble metal-based NCs have been reported, and most of them are achieved in harsh conditions (such as high temperatures78 and pressures910) or with a specific template111213. Syntheses of noble metal NCs with meta-stable crystal phases remain challenging, especially in mild synthetic conditions.…”