Atomic Carbon Layers Supported Pt Nanoparticles for Minimized CO Poisoning and Maximized Methanol Oxidation.

Maximizing activity of Pt catalysts toward methanol oxidation reaction (MOR) together with minimized poisoning of adsorbed CO during MOR still remains a big challenge. In the present work, uniform and well-distributed Pt nanoparticles (NPs) grown on an atomic carbon layer, that is in situ formed by means of dry-etching of silicon carbide nanoparticles (SiC NPs) with CCl4 gas, are explored as potential catalysts for MOR. Significantly, as-synthesized catalysts exhibit remarkably higher MOR catalytic activity (e.g., 647.63 mA mg-1 at a peak potential of 0.85 V vs RHE) and much improved anti-CO poisoning ability than the commercial Pt/C catalysts, Pt/carbon nanotubes, and Pt/graphene catalysts. Moreover, the amount of expensive Pt is a few times lower than that of the commercial and reported catalyst systems. As confirmed from density functional theory (DFT) calculations and X-ray absorption fine structure (XAFS) measurements, such high performance is due to reduced adsorption energy of CO on the Pt NPs and an increased amount of adsorbed energy OH species that remove adsorbed CO fast and efficiently. Therefore, these catalysts can be utilized for the development of large-scale and industry-orientated direct methanol fuel cells.

Particle size-control enables extraordinary activity of ruthenium nanoparticles/multiwalled carbon nanotube catalysts towards the oxygen reduction reaction.

Catalysts with high efficiency for the oxygen reduction reaction (ORR) play a vital important role in fuel cells and metal-air batteries. Herein, Ru nanoparticles are highly dispersed on functional multi-walled carbon nanotubes (MWCNTs) by a facile impregnation-reduction method. The particle sizes of Ru nanoparticles are simply and effectively adjusted by the concentration of the Ru precursor. Benefiting from the optimal Ru particle size (2.1 nm), a large electrochemically active surface area and fast electron transport, the Ru/MWCNT catalyst shows outstanding ORR activity and durability via a four-electron pathway, producing a diffusion-limited current density of 4.7 mA cm-2 with a half-wave potential of 0.72 V (vs. RHE). Such performance is better than that of a commercial 10 wt% Pt/C catalyst. Density functional theory calculation results reveal that the Oads adsorption on the surface of Ru increases gradually with the addition of the RuOx layer. The Ru/MWCNT catalyst with a particle size of 2.1 nm features appropriate Oads adsorption energy due to the formation of an optimal RuOx/Ru interface for the facilitation of the ORR.