H ₂ ‐induced thermal treatment significantly influences the development of a high performance low‐platinum core‐shell PtNi/C alloyed oxygen reduction catalyst

Abstract

Summary In the purpose of maximizing the utilization of noble metal Pt in oxygen reduction catalysts, we illustrate a synthesis method of preparing the low‐platinum PtNi/C alloyed oxygen reduction reaction (ORR) catalyst, which is developed through the H2‐induced treatment to a glucose reduced PtNi/C alloy. After post‐treatment with H2/N2 mixture gases, this catalyst displays excellent ORR catalytic activity and durability for the synergetic influences of electronic and geometry effects on catalysts during the alloying. Specifically, the as‐prepared PtNi/C (350°C‐6 h) sample delivers preponderant ORR activity with only 53.5% Pt usage than the commercial Pt/C. The specific activity and mass activity are corresponding 7.49 times and 3.5 times to the commercial Pt/C. This catalyst exhibits excellent ORR catalytic activity after 10 000 potential cycles in acid, which benefits from the well alloyed core‐shell structure of PtNi/C. H2‐induced thermal treatment has significant effects on the development of high performance low‐platinum PtNi/C alloy catalyst, and plays the significant role in the formation of well‐alloyed core‐shell structures. The lowered d‐band center is believed to facilitate ORR catalysis through weakening the adsorption of intermediate oxygen species on the alloyed Pt surface. Therefore, PtNi/C(350°C‐6 h) alloyed catalyst possesses outstanding ORR catalytic activity with much lower Pt loading.

Metal–Support Interactions in a Molybdenum Oxide Anchored PtNi Alloy for Improving Oxygen Reduction Activity

“…The difference of lattice shrinkage is caused by the alloy formed by Pt and Ni. It will affect the overlapping degree of Pt electron states, causing a downshift of the d-band center that weakens the adsorption strength of the oxygenated intermediate on the surface of the catalyst, which is beneficial for re-exposure of active sites. − …”

Improved platinum‐nickel nanoparticles with dopamine‐derived carbon shells for proton exchange membrane fuel cells

“…In addition to the PtNi peak in the XRD pattern of PtNi/C_700 C, a separate peak corresponding to Pt was observed. This was probably due to the segregation ascribed to the difference in the affinity to the supplied gas between the Pt and Ni, or the difference in their bonding strengths, which depended on the type of metal atom during annealing in a hydrogen atmosphere at 700 C. 22 This segregation should be avoided because it may inhibit uniform alloy formation and may also lead to the formation of isolated Pt nanoparticles. Interestingly, no isolated XRD peaks were observed for PtNi@C/C.…”

“…Interestingly, the Pt content on the surface of the nanoparticles slightly increased, which was probably due to the segregation of Pt during heat treatment in a hydrogen atmosphere. 22 Figure 2F,G are a single high-resolution TEM (HR-TEM) image of a PtNi nanoparticle and its pattern obtained using an inverse FFT process, respectively. The (111) interplanar distance, d-spacing, of the synthesized PtNi nanoparticles was approximately 2.18 Å, which was close to that of the Pt 1 Ni 1 alloy (2.17 Å), confirming the formation of a PtNi alloy with a uniform composition.…”

Core‐shell FeCo N‐doped biocarbons as stable electrocatalysts for oxygen reduction reaction in fuel cells

“…[1][2][3] However, the kinetic limitation of oxygen reduction reaction (ORR) in the cathode, poor long-term stability, high cost and scarcity of platinum based catalysts impede the large-scale industrialization of fuel cells. [4][5][6] In the recent years, investigations on the low cost, highly active and stable non-noble catalysts [7][8][9][10] for fuel cells were comprehensively carried out. According to the earlier reports, 9,[11][12][13][14][15][16][17][18][19] the development of M-N-C (M = transition metals) catalysts was shown to be very promising toward ORR.…”

“…With the high energy conversion efficiency and low contaminant emissions, fuel cells play a vital role in the sustainable community 1‐3 . However, the kinetic limitation of oxygen reduction reaction (ORR) in the cathode, poor long‐term stability, high cost and scarcity of platinum based catalysts impede the large‐scale industrialization of fuel cells 4‐6 . In the recent years, investigations on the low cost, highly active and stable non‐noble catalysts 7‐10 for fuel cells were comprehensively carried out.…”