Self‐Assembled Dendritic Pt Nanostructure with High‐Index Facets as Highly Active and Durable Electrocatalyst for Oxygen Reduction

Abstract

The durability issues of Pt catalyst should be resolved for the commercialization of proton exchange membrane fuel cells. Nanocrystal structures with high-index facets have been recently explored to solve the critical durability problem of fuel cell catalysts as Pt catalysts with high-index facets can preserve the ordered surfaces without change of the original structures. However, it is very difficult to develop effective and practical synthetic methods for Pt-based nanostructures with high-index facets. The current study describes a simple one-pot synthesis of self-assembled dendritic Pt nanostructures with electrochemically active and stable high-index facets. Pt nanodendrites exhibited 2 times higher ORR activity and superior durability (only 3.0 % activity loss after 10 000 potential cycles) than a commercial Pt/C. The enhanced catalytic performance was elucidated by the formation of well-organized dendritic structures with plenty of reactive interfaces among 5 nm-sized Pt particles and the coexistence of low- and high-index facets on the particles.

Improved Stability of Octahedral PtCu by Rh Doping for the Oxygen Reduction Reaction

“…[11][12][13][14][15][16][17] Besides, shape-controlled synthesis of PtÀ M alloy nanocrystals exposing specific facets can further elevate the ORR activity. [18][19][20][21] Extended Pt 3 Ni(111) single crystal surface has been reported to have the highest ORR activity, whose specific activity is 90-fold more active than the state-of-the-art Pt/C catalyst. [22] As a consequence, octahedral or icosahedral Pt 3 Ni nanocrystals bounded by (111) facets are widely explored to gain super high ORR activity.…”

“…bimetallic catalysts is an efficient approach to reduce the Pt usage by increasing the electrocatalytic activity [11–17] . Besides, shape‐controlled synthesis of Pt−M alloy nanocrystals exposing specific facets can further elevate the ORR activity [18–21] . Extended Pt 3 Ni(111) single crystal surface has been reported to have the highest ORR activity, whose specific activity is 90‐fold more active than the state‐of‐the‐art Pt/C catalyst [22] .…”

Electrochemical Analysis for Demonstrating CO Tolerance of Catalysts in Polymer Electrolyte Membrane Fuel Cells

“…As expected, the onset and peak potentials (0.45 and 0.57 V RHE , respectively) for the CO oxidation of Pt 1 Ru 1 /C were much lower than those (0.57 and 0.66 V RHE , respectively) of Pt 1 Ru 3 /C, indicating higher CO oxidation activity than Pt 1 Ru 3 /C [26]. However, it was clearly confirmed that the two PtRu/C catalysts still exhibit much higher CO oxidation activities due to the presence of surface Ru atoms compared to a bare Pt/C catalyst [27]. This result corresponded to that of previous reports showing that the change in the CO binding energy depends on the Ru content in PtRu alloys [13].…”

Simulation and design of energy materials accelerated by machine learning

“…Design novel cathode materials are also of great significance for improving the performance of LIBs. Molecular electrode materials have been widely used as a substitute for traditional transition metal oxides due to their low price, flexible and environmental friendliness . Finding excellent molecular electrode materials is still very challenging, as the organic structure space is very broad.…”

“…Besides the various combinations of bimetallic elements, the mixing ratio is also an influencing factor and Ulissi et al 54 screened all cases of bimetallic Ni x Ga y surfaces for CO 2 RR. Since there are multiple surface facets in the corresponding bulk composition, and adsorption sites on the same surface, it is hard to exhaustively filter all adsorptions configurations on the Ni x Ga y surface, thus the application of NN model can greatly simplify this workflow which is shown in Figure 2a and predict three most active surfaces NiGa(210), NiGa (110), and Ni 5 Ga 3 (021) for CO 2 RR of C1 and C2 products through only several thousand DFT calculation steps. For specific crystal surfaces, their catalytic activities are generally determined by adsorption.…”