Bimetallic PtAg alloyed nanoparticles and 3-D mesoporous graphene nanosheet hybrid architectures for advanced oxygen reduction reaction electrocatalysts

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 5; no. 44; pp. 23158 - 23169
• Main Authors: Li, Zesheng, Li, Yunyong, He, Chunyong, Shen, Pei Kang
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2017
• Subjects: Alloy development; Architecture; Bimetals; Catalysis; catalysts; Catalytic activity; Composite materials; Conductivity; Electrocatalysts; electrochemistry; electron transfer; Electron transport; Graphene; Ion diffusion; Nanoparticles; Nanosheets; Oxygen; Oxygen reduction reactions; Pore size; Porosity; porous media; surface area
• ISSN: 2050-7488; 2050-7496; 2050-7496
• DOI: 10.1039/C7TA07525A

Herein, three-dimensional mesoporous graphene conductive networks supporting bimetallic PtAg alloyed nanoparticles ( i.e. PtAg/3DMGS) with a superior composited nanostructure have been fabricated for advanced oxygen reduction reaction electrocatalysts. The unique architecture of 3D porous graphene exhibits a high surface area (1382 m 2 g −1 ), a well-defined mesoporous structure (an average pore size of 3.28 nm), as well as an excellent electronic conductivity (1350 S m −1 ). Inside the PtAg/3DMGS, high-density and ultrafine PtAg NPs (∼2.5 nm) were well dispersed on the porous surface of 3DMGS. The combination of ultrafine PtAg NPs and 3DMGS conductive networks provides a relatively stable macroporous composite architecture, which offers convenient binary channels for both electron transport and ion diffusion. This promising PtAg/3DMGS composite material reveals an ultrahigh mass activity (at 0.9 V) of 392 mA mg Pt −1 , which is nearly 4 times that of Pt/C (TKK) (102 mA mg Pt −1 ). After 1000 CV cycles, the retention rates of mass activity are 81.6% and 66.7% for PtAg/3DMGS and Pt/C (TKK), respectively. These results demonstrate that the PtAg/3DMGS composite material is a promising electrocatalyst with high catalytic activity and high stability for the oxygen reduction reaction.