Platinum Multicubes Prepared by Ni²⁺‐Mediated Shape Evolution Exhibit High Electrocatalytic Activity for Oxygen Reduction

Abstract

Pt(100) facets are generally considered less active for the oxygen reduction reaction (ORR). Reported herein is a unique Pt-branched structure, a multicube, whose surface is mostly enclosed by {100} facets but contains high-index facets at the small junction area between the adjacent cubic components. The synthesis is accomplished by a Ni(2+) -mediated facet evolution from high-index {311} to {100} facets on the frameworks of multipods. Despite the high {100} facet coverage, the Pt multicubes exhibit impressive ORR activity in terms of half-wave potential and current density nearly to the level of the most active Pt-based catalysts, while the durability of catalysts is well retained. The facet evolution creates a set of samples with tunable ratios of high-index to low-index facets. The results reveal that the excellent ORR performance of Pt multicubes is a combined result of active sites by high-index facets and low resistance by flat surface. It is anticipated that this work will offer a new approach to facet-controlled synthesis and ORR catalysts design.

Pt‐Pd Bimetal Popcorn Nanocrystals: Enhancing the Catalytic Performance by Combination Effect of Stable Multipetals Nanostructure and Highly Accessible Active Sites

“…In contrast, the present Pt‐Pd 3D structures have concaves or open potholes at the unit center, that is surrounded by several petals. Different from the previously reported multioctahedral or multicubic Pt nanocrystals, which were surrounded by several regular branches that are mainly the single facets of {111} or {100}, respectively, the present popcorns display irregular and rough surface with several petals in the 3D space. The 3D stretching morphologies make the nanostructures to have more assessable surfaces, which allows the existence of high active sites …”

“…Figure shows the CV profiles of the carbon supported popcorns, the commercial Pt/C and Pt black catalyst. All the catalysts exhibit distinctive hydrogen adsorption in the negative scan and hydrogen desorption in the positive scan in the potential region of 0.05–0.40 V. The peaks at ≈0.13 and ≈0.27 for the characteristic hydrogen desorption on (110) and (100) surfaces, respectively, can be observed clearly on the popcorn catalysts . The current for hydrogen adsorption/desorption on (100) increases with increasing the Pd content .…”

“…Pt3Pd1 (0.592 mA cm −2 ) and Pt1Pd3 (0.460 mA cm −2 ) are also present 3.6 and 2.8 times enhancements in activities relative to the benchmark Pt/C, respectively. The high catalytic activities of popcorn catalysts are more likely attributed to the Pt‐Pd bimetal composition and the unique nanostructures consisting of many rough surfaces or dense concaves with high accessibility . The multipetal structure with high dense accessible active sites contributes to the high activity.…”

Controlled Synthesis of Octahedral Platinum‐Based Mesocrystals by Oriented Aggregation

“…[2] On the other hand, metal nanoparticles can also serve as the monomers, which affords af amily of mesocrystals by oriented aggregation, [3] showing highly ordered mesoscale superstructures and typicallyc rystallike morphology. Typically,t he mesocrystals are superior to individualn anocrystals as af amily of self-supported catalysts,w hich ensures not only accessibility of large surfacea reas of the crystallites for highc atalytic activi-ty, [5] buta lso outstanding stability and durability due to the integrityo ft he mesostructure. Typically,t he mesocrystals are superior to individualn anocrystals as af amily of self-supported catalysts,w hich ensures not only accessibility of large surfacea reas of the crystallites for highc atalytic activi-ty, [5] buta lso outstanding stability and durability due to the integrityo ft he mesostructure.…”

Some recent developments in surface and interface design for photocatalytic and electrocatalytic hybrid structures

“…16,17 On the other hand, some additional interfacial effects such as surface polarization effect may play important 70 roles in tuning the molecular activation ability of catalyst surface. 18,[22][23][24][25][26][27][28] This two-way research mode has been widely used for catalyst design and catalytic mechanism research. 5 To date, catalytic mechanism research has guided us to design the surface and interface for high-performance photocatalysts and electrocatalysts toward our demand, 19 while advanced synthetic approaches can help to put the designs into reality.…”