Introducing oxophilic metals into Pt‐based alloy catalysts can effectively alleviate the poisoning by CO intermediates (CO*) during methanol oxidation reactions (MOR). However, excessive oxophilic metals on the surface of catalysts tend to form thermodynamically stable carbonyl compound‐like structures, occupying electrocatalytically active sites, which is not conducive to the enhancement of catalytic activity. Herein, a kind of surface segregated FePtRh nanoflowers for effectively eliminating the CO* poisoning during MOR electrocatalysis is presented. The FePtRh nanoflowers are constituted by the Rh‐rich core and Fe‐rich shell. The optimized Fe21Pt66Rh13/C shows a high mass activity of 3.90 A mgPt−1 and a specific activity of 4.85 mA cm−2. It is confirmed that the electron transfer from Pt to Rh or Fe atoms is beneficial for the higher anti‐CO poisoning ability, which mainly originate from the alloying of Rh atoms and surface‐segregated structures. Density functional theory calculations reveal the decreased electrons adsorbed by CO* on both Pt–Pt bridge sites and top sites weakens the strong adsorption energy between Pt atoms and CO* intermediates. The optimal nanoflowers also show excellent performance toward ethanol oxidation reaction (EOR) with a high mass activity of 2.76 A mgPt−1 and the enhanced anti‐CO poisoning ability, as well as the improved stability.
Tuning asymmetric coordination of metal single-atom (SA) sites can provide a new opportunity for optimizing the electronic structure of catalysts to achieve efficient catalysis, however, achieving such controllable design remains a grand challenge. Herein, an asymmetrically coordinated Co-N 4 P SA site as a new catalyst system for achieving superior dehydrogenation catalysis of formic acid (HCOOH) is reported. The experimental results show that the Co atom is coordinated by four N atoms and one asymmetric P atom, forming the unique Co-N 4 P SA sites. The Co-N 4 P SA sites exhibit an impressive mass activity of 4285.6 mmol g -1 h -1 with 100% selectivity and outstanding stability for HCOOH dehydrogenation catalysis at 80 °C, which is 5.0, 25.5, and 23.1 times that of symmetrically coordinated Co-N 4 SA sites, commercial Pd/C and Pt/C, respectively. The in situ ATR-IR analysis demonstrates the mono-molecular H 2 produced mechanism over Co-N 4 P SA sites, and theoretical calculations further reveal that the asymmetric P sites not only can boost the CH bond cleavage of HCOO* by largely reducing the energy barrier but also facilitate the proton adsorption to achieve the fast generation of H 2 in Co-N 4 P SA sites. This study opens a new way for rationally designing novel SA sites to achieve efficient catalysis.
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