Abstract
The one-step vacuum carbonization synthesis of a platinum nano-catalyst embedded in a microporous heterocarbon (Pt@cPIM) is demonstrated. A nitrogen-rich polymer of an intrinsic microporosity (PIM) precursor is impregnated with PtCl₆ 2- to give (after vacuum carbonization at 700 °C) a nitrogen-containing heterocarbon with embedded Pt nanoparticles of typically 1⁻4 nm diameter (with some particles up to 20 nm diameter). The Brunauer-Emmett-Teller (BET) surface area of this hybrid material is 518 m² g -1 (with a cumulative pore volume of 1.1 cm³ g -1) consistent with the surface area of the corresponding platinum-free heterocarbon. In electrochemical experiments, the heterocarbon-embedded nano-platinum is observed as reactive towards hydrogen oxidation, but essentially non-reactive towards bigger molecules during methanol oxidation or during oxygen reduction. Therefore, oxygen reduction under electrochemical conditions is suggested to occur mainly via a 2-electron pathway on the outer carbon shell to give H₂O₂. Kinetic selectivity is confirmed in exploratory catalysis experiments in the presence of H₂ gas (which is oxidized on Pt) and O₂ gas (which is reduced on the heterocarbon surface) to result in the direct formation of H₂O₂.
Original language | English |
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Article number | 542 |
Pages (from-to) | 1-14 |
Number of pages | 14 |
Journal | Nanomaterials |
Volume | 8 |
Issue number | 7 |
DOIs | |
Publication status | Published - 18 Jul 2018 |
Funding
Funding: N.H.-I. and J.I. thank MINICINN, Spain (projects CTQ2013-48280-C3-3-R and CTQ2016-76231-C2-2-R) for financial support and the University of Alicante for support for a Ph.D. exchange visit. F.M. and N.B.M. thank the Leverhulme Foundation for financial support (RPG-2014-308: “New Materials for Ionic Diodes and Ionic Photodiodes”). Acknowledgments: J.K.E., A.G.R.H. and F.M. thank the Catalysis DTC in Cardiff. D.H. thanks the Royal Society for a Newton International Fellowship.
Keywords
- Bifunctional catalysis
- Heterocarbon
- Microporosity
- Peroxide
- Voltammetry
ASJC Scopus subject areas
- General Materials Science
- General Chemical Engineering