External and Internal Interface-Controlled Trimetallic PtCuNi Nanoframes with High Defect Density for Enhanced Electrooxidation of Liquid Fuels

Abstract

Selectively exposing active surfaces of Pt-based nanoframes (NFs) can promote electrocatalysis of small organic molecules, especially regarding improved diffusion and anti-poisoning properties. However, the systematic investigation on the synthesis, as well as structure-property relationship, of Pt-based NFs with tunable external and internal surface structures is still at its early stage. Herein, we report a facile, environmental and one-pot approach to fabricate PtCuNi NFs with tunable external and internal surface structures by flexibly adjusting coordination and reducing agents. Interestingly, electrocatalytic results reveal that the PtCuNi NFs with variable external structures possess higher performance (activity and anti-CO-poisoning capability) than those with tunable internal structures as well as commercial Pt/C. Especially, the PtCuNi eb-NFs (external branch NFs) exhibit the excellent specific activities of methanol and formic acid electrooxidation reactions (MOR and FAOR), 10.7 and 7.9 times higher than those of commercial Pt/C, respectively. The PtCuNi eb-NFs also possess a superior diffusion ability for methanol electrooxidation (0.0276) and formic acid electrooxidation (0.0153) compared to other PtCuNi NFs with plentiful internal surface. The enhanced MOR and FAOR activities of PtCuNi eb-NFs are ascribed to its abundant external surface area and high defect-density (e.g. vacancy, subtle lattice distortion and high-index facets), which results in an optimal anti-CO-poisoning capability due to the diffusion and ligand effects. This work opens up a new pathway for enhancing the electrooxidation properties (anti-poisoning property and diffusion rate) of liquid fuels by tuning the surface structures of nanoframe catalysts.

Shape controlled iron oxide nanoparticles: inducing branching and controlling particle crystallinity

“…1 They have shown increased activity in catalysis due to the higher proportion of high index facets exposed. 1,[3][4][5] Another example is in biomedical applications where multi-core magnetic NPs, often called nanoflowers, have been shown to be ideal candidates for magnetic hyperthermia. [6][7][8][9][10] For magnetic hyperthermia the key characteristics making these shapes ideal is thought to be their magnetic anisotropy and core-core interactions, with the best properties coming from having multiple aligned crystalline domains.…”

“…Etching typically occurs either during the growth or via a post-preparative step to remove material selectively from faceted surfaces and rearrange the particle into a multiply branched structure. 5,11 In aggregative growth mechanisms the final particles can be made up of aligned 6 or unaligned 12 crystal domains. The alignment of the crystal domains to form a single crystal occurs via aggregation in solution called oriented attachment where the facets of growing particles align in solution.…”

Interface‐Rich Three‐Dimensional Au‐Doped PtBi Intermetallics as Highly Effective Anode Catalysts for Application in Alkaline Ethylene Glycol Fuel Cells

“…The transmission electron microscopy (TEM) image (Figure 1b) displayed that the 3D structures were constructed from small nanoparticles interconnected in a 3D manner, resulting in abundant interfacial nanoboundaries (Figure 1c) and favoring the electrocatalytic activity. [ 32–36 ] The size of the small nanoparticles was below 6.6 nm. The high‐resolution TEM (HRTEM) image (Figure 1d) of the Pt 53.1 Bi 43.4 Au 3.5 sample indicated the clear lattice fringes with the interplanar spacing of 0.215 nm corresponding to the (110) plane of the intermetallic Pt–Bi phase.…”

Manipulating Interfaces of Electrocatalysts Down to Atomic Scales: Fundamentals, Strategies, and Electrocatalytic Applications

“…In addition, when one considers some specific energy terms originated from strain, [ 111,112 ] defect, [ 113,114 ] and surface states, [ 115,116 ] Equation (2) should be corrected with some additional terms, and the interfacial formation temperature ( T A + B → AB ) shall be modified. For example, T A + B → AB will decrease with an increase in the matching level between epitaxial crystal facets from A and B, respectively, due to the decrease of bond energy.…”