Platinum dendrites with controlled sizes for oxygen reduction reaction

Study on Oxygen Evolution Reaction of Ir Nanodendrites Supported on Antimony Tin Oxide

In this study, the iridium nanodendrites (Ir NDs) and antimony tin oxide (ATO)-supported Ir NDs (Ir ND/ATO) were prepared by a surfactant-mediated method to investigate the effect of ATO support and evaluate the electrocatalytic activity for the oxygen evolution reaction (OER). The nano-branched Ir ND structures were successfully prepared alone or supported on ATO. The Ir NDs exhibited major diffraction peaks of the fcc Ir metal, though the Ir NDs consisted of metallic Ir as well as Ir oxides. Among the Ir ND samples, Ir ND2 showed the highest mass-based OER catalytic activity (116 mA/mg at 1.8 V), while it suffered from high degradation in activity after a long-term test. On the other hand, Ir ND2/ATO had OER activity of 798 mA/mg, and this activity remained >99% after 100 cycles of LSV and the charge transfer resistance increased by less than 3 ohm. The enhanced durability of the OER mass activities of Ir ND2/ATO catalysts over Ir NDs and Ir black could be attributed to the small crystallite size of Ir and the increase in the ratio of Ir (III) to Ir (IV), improving the interactions between the Ir NDs and the ATO support.

Evolution of Pt truncated octahedra to nanodendrites during the synthesis in methanol–water solution

The size and shape of the Pt particles could be tuned from truncated octahedra (3.5 nm) to nanodendrites (13.5 nm) by simply varying the CH₃OH/H₂O ratio in the synthetic solution.

CO oxidation on SnO2 surfaces enhanced by metal doping

Doping metal atoms into a host metal oxide lattice can enhance its catalytic activity by modulating the properties of surface oxygen.

High Durable Ternary Nanodendrites as Effective Catalysts for Oxygen Reduction Reaction

Exploiting high catalytic activities and superior durability is significant for the lifetime and the cost of electro-catalysts for oxygen reduction reaction (ORR). Pt-Ni nanocrystals have attracted considerable attention owing to their exceptionally catalytic performance. However, the durability of Pt-Ni nanoparticles in acid media is still far below satisfaction. Consequently, improving the durability is extremely urgent for the application of Pt-Ni catalysts. To this end, we herein develop Pt-Ni-Ir ternary nanocrystals with dendritic shape, which are synthesized through a facile one-pot strategy. Such nanostructures featured with multibranches show an area specific activity of 1.58 mA cm(-2), seven times more than that of the commercial Pt/C catalyst (0.21 mA cm(-2)). More importantly, the dendritic Pt-Ni-Ir catalyst displays extraordinarily high durability. In contrast to the commercial Pt/C counterparts, which exhibit losses of 53.2% in EASA and 41% in area specific activity after 12 000 cycles of sweeping in the potential range of 0.6-1.1 V, only respective losses of 5.5% and 6% are detected for our dendritic Pt-Ni-Ir catalyst. The high activity and remarkable durability are mainly attributed to the dendritic morphology and the introduction of Ir. This work demonstrates that the Pt-Ni-Ir dendritic nanostructures are promising electro-catalysts for ORR.

A versatile strategy to fabricate MOFs/carbon material integrations and their derivatives for enhanced electrocatalysis

This work proposed a versatile strategy to fabricate MOFs/carbon materials integrations for enhanced electrocatalysis.

Pt monolayer coating on complex network substrate with high catalytic activity for the hydrogen evolution reaction

A deposition process has been developed to fabricate a complete-monolayer Pt coating on a large-surface-area three-dimensional (3D) Ni foam substrate using a buffer layer (Ag or Au) strategy. The quartz crystal microbalance, current density analysis, cyclic voltammetry integration, and X-ray photoelectron spectroscopy results show that the monolayer deposition process accomplishes full coverage on the substrate and the deposition can be controlled to a single atomic layer thickness. To our knowledge, this is the first report on a complete-monolayer Pt coating on a 3D bulk substrate with complex fine structures; all prior literature reported on submonolayer or incomplete-monolayer coating. A thin underlayer of Ag or Au is found to be necessary to cover a very reactive Ni substrate to ensure complete-monolayer Pt coverage; otherwise, only an incomplete monolayer is formed. Moreover, the Pt monolayer is found to work as well as a thick Pt film for catalytic reactions. This development may pave a way to fabricating a high-activity Pt catalyst with minimal Pt usage.

Formation of hierarchical structures of Fe2O3 by the liquid–liquid interface technique

We report the formation of dendritic hierarchical structures of α-Fe₂O₃ and nanostructures of Fe₂O₃ by the simple liquid–liquid interface method.

In situ shaping of Pt nanoparticles directly overgrown on carbon supports

Pt cubes immobilized on carbon supports were synthesized by a one pot process in the presence of anchoring agents. The anchoring agents provide nucleating sites on the support, and also act as shape-controlling agents. In situ shaped cubic Pt/C showed superior activity and long-term stability for oxygen reduction reaction without an organic removal process.