Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
LABORATORY OF NANOTECHNOLOGY NATIONAL INSTITUTE FOR RESEARCH AND DEVELOPMENT IN MICROTECHNOLOGIES, IMT BUCHAREST, www.imt.ro Metallic – semiconductor nanosystem assembly for miniaturized fuel cell applications Mihaela Miu*, Irina Kleps, Teodora Ignat, Monica Simion, Adina Bragaru * [email protected] Metallic nanoparticles present an enhanced electro-activity comparing with macroelectrodes due to their high surface-to-volume ratio and their integration in complex devices allows improving of the sensor sensitivity or fuel cell efficiency, for example → A new metallic- semiconductor nanosystem on Si has been studied for potential integration in a micro fuel cell as membrane electrode assembly (MEA) using specific processes to nano- micro-electromechanical system (N/MEMS) technology the Pt catalyst support polished silicon wafer nanosilicon 1 2 Silicon membrane has been subjected to an electrochemical process spherical SiO2 nanoparticles offering similar huge area for leading to porosification (nanostructuration) and consequently the catalyst deposition, with similar size have been used as support increase of the surface area and the density of chemically active sites fabricated using a precipitation technique based on controlled Si membrane morphology depends on process parameters, and the pores diameter can be tuned from nm to µm hydrolysis of a silicon alkoxide (tetraethylorthosilicate - TEOS) From few nm to hundreeds of nm pores in a mixture of ethanol containing aqueous ammonia. 70 – 100 nm diameters A Pt precursor solution (3.5mM H2PtCl6) was used for chemical impregnation EDX spectrum for nanoPt on big SiO2 nanoparticles (90 nm) EDX spectrum for nanoPt on PS XRD analyses reveal the presence of (111) and EDAX analyses reveal the improvement of Pt distribution related to the diminish of SiO2 nanoparticle size (200) crystallinity phases of Pt nanoparticles In-plane diffraction Spectru continuu-Mo 2000 300 Si(400) 1800 Pt(111) 1600 200 Pt(200) 1400 Pt crystallite phase distribution function Lin (Counts) I [Imp/10sec] ALM35 100 1200 (a) 10 nm (b) 30 nm Si pores Si pores 29.2 nm 0 1000 32 40 50 60 70 80 2-Theta - Scale 12 26.8 nm EDX spectrum for nanoPt on small SiO2 nanoparticles (18 nm) 14 16 18 20 22 24 26 o 2 [ ] File: (a) S1 PhaseID 300sm.raw - Step: 0.010 ° - Step time: 300. s File: (b) S4 PhaseID 300s_01_step0d05m.raw - Step: 0.050 ° - Step time: 300. s 00-001-1194 (D) - Platinum - Pt 90