Vertex‐Type Engineering of Pt–Cu–Rh Heterogeneous Nanocages for Highly Efficient Ethanol Electrooxidation

Abstract

Mastery over the architecture and elemental distribution of metal nanocrystals at the nanoscale can effectively tailor and improve their catalytic properties. Herein, the vertex‐type‐selective growth of metallic nanohorns on a central nanocrystal is constructed via a one‐pot solvothermal synthesis, despite the fact that the site‐selective epitaxy of the second phase proceeds on all the vertices of the seeds. The prepared vertex‐type‐selective Pt–Cu–Rh heterogeneous nanocages (HNCs) are composed of a Rh‐decorated Pt–Cu rhombic dodecahedral nanocage and six Pt–Cu–Rh nanohorns protruding from the {100} rather than the {111} vertices of rhombic dodecahedron. Impressively, the Pt–Cu–Rh HNCs exhibit 8.1 times higher specific and 6.8 times higher mass activity toward the ethanol oxidation reaction under acidic conditions than commercial Pt/C catalysts. Besides, the peak potential for CO oxidation on Pt–Cu–Rh HNCs (370.4 mV vs SCE) is 182.0 mV more negative than that on Pt/C, indicating the dramatically enhanced CO tolerance. The excellent electrocatalytic property is attributed to the synergistic effect between Pt, Cu, and Rh components, high specific surface area of nanocages and nanohorns, as well as abundant concave/convex sites and various high‐index facets around the surface.

Well‐Defined Platinum Surfaces for the Ethanol Oxidation Reaction

“…All of the aforementioned catalysts showed a high activity toward EOR with peak currents several times higher than that obtained on a commercial catalyst of the equivalent metal supported on carbon. One of the most interesting contributions was developed by Wang et al., who synthesized Pt−Cu−Rh nanocages containing abundant stepped atoms and various high‐index facets around the surface . Electrochemical tests showed that Pt−Cu−Rh HNCs exhibited an outstanding activity (peak current of 7300 A/cm −2 ) attributed to the synergistic effect between Pt, Cu, and Rh components, its high specific surface area, as well as abundant concave/convex sites and the various high‐index facets around the surface.…”

Boosting Both Electrocatalytic Activity and Durability of Metal Aerogels via Intrinsic Hierarchical Porosity and Continuous Conductive Network Backbone Preservation

“…Fuel cells are promising renewable energy devices for advanced portable electronic devices and electrical vehicles. [ 1,2 ] They can convert chemical energy into electrical power via the electrocatalytic processes including the methanol oxidation reaction (MOR), [ 3 ] ethanol oxidation reaction, [ 4 ] oxygen reduction reaction (ORR), [ 5 ] hydrogen oxidation reaction (HOR), [ 6 ] etc. To date, platinum (Pt) is still considered as the most promising and commonly used electrocatalyst in fuel cells.…”

“…To date, platinum (Pt) is still considered as the most promising and commonly used electrocatalyst in fuel cells. [ 1–6 ] However, the insufficient activity, inadequate durability, and the high cost and scarcity of Pt hinder the practical large‐scale commercialization of fuel cells.…”

“…[ 3–14 ] One strategy is alloying Pt with nonprecious transition metals (e.g., Fe, Co, Ni, and Cu), to improve the intrinsic catalytic activity via ligand and strain effects through modifying the electronic environment of Pt surface atoms. [ 4–8,11 ] Another strategy is maximizing the utilization efficiency of Pt atoms by designing hollow and porous nanostructures or reducing particle size in the Pt‐based nanocatalysts, such as nanoframes, [ 8 ] nanocages, [ 5,12 ] ultrafine nanowire, [ 10,13 ] or even single atom Pt, [ 14 ] etc. Generally, these Pt‐based nanocatalysts are supported on carbon black with high electrical conductivity and high surface area to achieve a uniform dispersion and obtain high activity and high stability.…”

“…Generally, these Pt‐based nanocatalysts are supported on carbon black with high electrical conductivity and high surface area to achieve a uniform dispersion and obtain high activity and high stability. [ 4–13 ] Unfortunately, carbon corrosion problems frequently happen in the acidic electrolyte under the high operation potential (>1.0 V RHE ) caused by start‐up/shut‐down (SUSD) sequences of fuel cells, leading to pronounced detachment of the Pt‐based nanocatalysts and low long‐term durability during the practical operation of fuel cells. [ 15,16 ]…”