Polyethyleneimine decorated graphene oxide-supported Ni1−xFex bimetallic nanoparticles as efficient and robust electrocatalysts for hydrazine fuel cells

Abstract

A very efficient, in situ growth approach has been developed to fabricate a graphene oxide (GO)-supported, highperformance Ni 1−x Fe x loading electrocatalyst. Transition metal nanoparticles (NPs) such as Ni are quite attractive due to their advantages in cost, and excellent electrocatalytic activity for hydrazine electrooxidation. However, their strong aggregation propensity makes it difficult to develop them into highly efficient electrocatalysts.Polyethyleneimine (PEI), a branched polyelectrolyte, is devised to resolve this problem, and is utilized to uniformly anchor Ni-Fe NPs on GO. Meanwhile, partial GO can be reduced to reduced graphene oxide (rGO) in the presence of amine-containing molecules, which is favourable to enhance the electrical conductivity of supporting materials.Ni 1−x Fe x NPs (50% loading) are prepared by a co-reduction method of metal precursors with hydrazine hydrate under 100 °C for 3 h. The content of PEI attached on GO significantly affects the dispersion and size of the resulting Ni 1−x Fe x NPs. Transmission electron microscope (TEM) images reveal that the Ni 1−x Fe x NPs with an average size of 8 nm are homogeneously dispersed on PEI-rGO 10 : 1 sheet. The electrochemical measurements indicate that the Ni 1−x Fe x /PEI-rGO 10 : 1 hybrid with a Ni : Fe mass ratio of 80 : 20 exhibits the highest electrocatalytic activity toward hydrazine oxidation, while the PEI-rGO 10 : 1 supporting material plays an excellent role in the synergistic catalytic effect. Under the same conditions, the electrocatalytic activity of Ni 80 Fe 20 NPs on PEI-rGO 10 : 1 for hydrazine is 2 times higher than that of the Ni 80 Fe 20 NPs directly deposited on GO.

Biomolecule-assisted synthesis of porous PtPd alloyed nanoflowers supported on reduced graphene oxide with highly electrocatalytic performance for ethanol oxidation and oxygen reduction

“…Interestingly, it can be observed that these peaks are coincidently appeared between bulk Pt (JCPDS-04-0802) and Pd (JCPDS-46-1043), further showing the alloyed nature of Pt with Pd [31]. Furthermore, there is almost no any other peak emerged for porous PtPd NFs-RGO, which is much distinguished from that of GO with a sharp peak centered at 11 corresponding to the (0 0 1) planes of graphite oxide [32], evidencing the efficient removal of oxygenous functional groups from RGO during the reduction process [13].…”

“…Raman analysis was performed to characterize the electronic and structural properties of graphite materials [32]. As illustrated in Fig.…”

One-Pot Synthesis of Hierarchical Flower-Like Pd-Cu Alloy Support on Graphene Towards Ethanol Oxidation

“…The significant weight loss of GO, around 28% between 100 and 300 °C, was mainly due to the removal of oxygen-containing functional groups, just like C–O and C=O. And the weight loss within 100 °C which came from the escape of water molecules between the RGO nanosheets as well as the weight loss above 500 °C was due to the combustion of carbon skeleton [ 27 , 31 , 32 ]. The result indicated the removal of the oxygen-containing functional groups on Pd-Cu (P) /RGO and Pd-Cu (F) /RGO, which further confirms that GO was efficiently reduced to RGO during the synthesis [ 23 ].…”

Two‐Dimensional Layered Materials as Catalyst Supports

“…The attachment of PEI at GO surface significantly affected the dispersion and size of the metal NPs. The electrochemical results indicated that the Ni 80 Fe 20 /PEI‐rGO hybrid exhibited superior catalytic activity over Ni 80 Fe 20 NPs directly deposited on GO in the hydrazine oxidation reaction . Further, Song et al.…”