High‐Temperature Confinement Synthesis of Supported Pt–Ni Nanoparticles for Efficiently Catalyzing Oxygen Reduction Reaction. (25th February 2022)

• Record Type: Journal Article
• Authors: Wang, Kun; Wang, Yifan; Geng, Shipeng; Wang, Yi; Song, Shuqin
• Is Part Of: Advanced functional materials. Volume 32:Number 22(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-25
• Subjects: confinement synthesis -- dealloying -- oxygen reduction reaction -- Pt–Ni alloy; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202113399
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Developing efficient Pt‐based alloy as oxygen reduction reaction (ORR) electrocatalysts is critical for practical applications of fuel cells. High‐temperature reduction technology can improve the alloy atoms ordering but inevitably accelerate metal sintering. Here, Pt–Ni nanoparticles (<5 nm) embedded into ordered mesoporous carbon (OMC) matrix are developed, and its confinement effect suppresses nanoparticles sintering up to 900 °C. After an elaborative dealloying process, the surface structure of Pt–Ni nanoparticles changes from a Ni‐rich to Pt‐rich layer (the thickness is about 0.15 nm). The optimized sample (PtNi3 @OMC‐A) displays outstanding mass and specific activities of 2.11 A mgPt –1 and 3.23 mA cmPt –2, more than one order of magnitude higher than commercial Pt/C (20 wt%). PtNi3 @OMC‐A also exhibits long‐term stability with a negligible activity loss after 10 000 potential cycles. Both experimental results and density functional theory calculations reveal that alloying effect as well as strain effect weaken Pt–O binding strength, thus resulting in an outstanding ORR activity. Furthermore, the high long‐term stability can be attributed to the confinement of OMC, inhibiting the detachment or agglomeration of the embedded alloy nanoparticles. Abstract : Pt–Ni nanoparticles (≈5 nm) embedded into ordered mesoporous carbon (OMC) is synthesized via high‐temperature reduction technology. The confinement effect of OMC can suppress nanoparticles sintering up to 900 o C. Both alloying effect and strain effect weaken Pt–O binding strength and accelerate the desorption of oxygenated species on the sample surface, thus resulting in an outstanding ORR performance.