(140c) MOF-Derived PtCo/Co3O4 nanocomposites in Carbonaceous Matrices As High-Performance ORR Electrocatalysts Synthesized Via laser Ablation Techniques
- Conference: AIChE Annual Meeting
- Year: 2021
- Proceeding: 2021 Annual Meeting
- Group: Nanoscale Science and Engineering Forum
- Time: Monday, November 8, 2021 - 1:10pm-1:25pm
Rapidly expanding global energy demands due to fast-paced human-technology interfaces have propelled fuel cell technology as a sustainable energy-conversion alternative. Nonetheless, the rational development of such technology demands the engineering of low-cost durable materials that can exhibit and retain specific electrocatalytic activities to sustain the electrochemical energy conversions. Over the years, our group has extensively developed the now-patented laser ablation synthesis in solution-galvanic replacement reaction (LASiS-GRR) technique as a non-equilibrium, one-pot and green route for synthesizing disparate heteronanostructured intermetallic composites1,2 including Metal Organic Frameworks (MOF)3 without using any surfactants/ligands, that can be tuned for diverse interfacial activities (energetics, optical, electrochemical). Herein, we specifically present LASiS-GRR as a facile route for the synthesis of Pt-Co bimetallic nanoparticles (NPs) encapsulated in MOF phases of ZIF-67 that are concurrently formed during the laser ablation process.4 Upon pyrolytic post-treatments, these composite structures are found to be partially altered, giving rise to the formation of graphitic shell coated Pt-Co bimetallic nanocomposites (NCs) that are spatially framed onto Co3O4-decorated carbonaceous matrices. Our investigations into the effects of Pt precursor (K2PtCl4) concentrations during the LASiS-GRR technique indicate that increasing K2PtCl4 initial concentrations in the solution-phase facilitate a higher degree of Pt-Co alloying. Subsequent electrochemical characterizations reveal the ability of these hybrid NCs in carbonaceous matrices to exhibit superior electrocatalytic activities towards oxygen reduction reaction (ORR) while maintaining long-term stability in highly concentrated alkaline media (KOH 1M). Specifically, the NCs synthesized from LASiS under 125 mg·L-1 K2PtCl4 solution,demonstrate an extraordinary 5-fold enhancement in their specific mass activities as compared to state-of-the-art commercial Pt catalysts. These outstanding performances are attributed to the unique configurations arising from cooperative catalytic activities (spill-over effects) between the graphitic shell coated bimetallic Pt-Co nanoparticles and the electrochemically active Co3O4-decorated carbon matrix support.
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- Hu S, Tian M, Ribeiro EL, Duscher G, Mukherjee D. Tandem laser ablation synthesis in solution-galvanic replacement reaction (LASiS-GRR) for the production of PtCo nanoalloys as oxygen reduction electrocatalysts. Journal of Power Sources. 2016;306:413-423.
- Ribeiro EL, Davari SA, Hu S, Mukherjee D, Khomami B. Laser-induced synthesis of ZIF-67: a facile approach for the fabrication of crystalline MOFs with tailored size and geometry. Materials Chemistry Frontiers. 2019;3(7):1302-1309.
- Ribeiro EL, Davis EM, Mokhtarnejad M, Hu S, Mukherjee D, Khomami B. MOF-derived PtCo/Co3O4 nanocomposites in carbonaceous matrices as high-performance ORR electrocatalysts synthesized via laser ablation techniques. Catalysis Science & Technology. 2021.