High Efficiency Solar-based Catalytic Structure for CO 2 Reforming DOE NETL# DE-FE0004224 By: Dr. Hisham Menkara Principal Investigator PhosphorTech Corporation Kennesaw, Georgia U.S. Department of Energy National Energy Technology Laboratory Carbon Storage R&D Project Review Meeting Developing the Technologies and Infrastructure for Carbon Capture and Storage August 20-22, 2013 PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Outline • Benefits to the Program • Project Goals and Objectives • Technical Status – Conventional vs hybrid heterojunction systems – Solution-based synthesis of photocatalyst materials & structures – Glancing Angle Deposition (GLAD) of metal oxides by IAD – Chemical products selectivity and detection – CO 2 reforming results and concept feasibility using biomass • Accomplishments to Date • Summary • Appendix PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Benefits to the Program Benefit Statement : Critical challenges identified in the utilization focus area include • the cost-effective use of CO 2 as a feedstock for chemical synthesis or its integration into pre-existing products. The efficiency of these utilization processes represents a critical challenge. This research is developing a set of materials and systems useful in converting CO 2 into other useful chemicals using sunlight as energy. Organic Photocatalyst Inorganic Photocatalyst CO 2 CO 2 -- - Photo- Fuel+Useful Starch+O 2 catalyst Compounds Particle + + + H 2 O H 2 O PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Program Goals • The goal of this project is to develop and demonstrate a novel photocatalytic structure and solar-based reactor having high CO 2 reforming potential, and high utilization of solar solar energy. – Phase I : Development & optimization of low-cost solution-based coating processes • Objectives: to develop solution-based thin-film coating processes for controlled and uniform coating of TiO 2 and NBG semiconductors on various substrates. Optical and physical properties will be measured and optimized. – Phase II: Development, fabrication, & characterization of p-n structures for CO 2 reduction • Objectives: to develop and fabricate p-n structures using optimized thin-films and demonstrate CO 2 reforming potential into fuels and chemicals – Phase III: Refinement of CO 2 reactor and prototype demonstration • Objectives: to build a CO 2 reactor prototype and refine p-n structure for maximum yield and energy conversion efficiency PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Photocatalyst Technology Challenge Photo-synthetically Active Radiance (PAR) U V IR PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Conventional vs Hybrid Photocatalysts n-type p-type A. Nishimura, Catalysis Today 148 (2009)341–349 Competing reduction reaction leads to hydrogen formation Hybrid System 4H + + 4e - 2 H 2 Conventional (Patent-pending) System Methane formation CO 2 + 8H + + 8e - CH 4 + 2 H 2 O • PN junction acts as an efficient e-h • High recombination rate of photo- Carbon monoxide formation separator generated electron-hole pairs CO 2 + 2H + + 2e - CO + H 2 O • Metal-free surfaces lead to increased • Excess metal loading leads to Methanol formation CO 2 + 6H + + 6e - CH 3 OH + H 2 O light absorption increased light reflection Formic acid formation • Semiconductors with different band • Hydrogen is formed by competing CO 2 + 2H + + 2e - HCO 2 H gaps can be used to harvest more Formaldehyde formation reduction reactions CO 2 + 4H + + 4e - CH 2 O + H 2 O solar energy PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Photocatalytic Reactor Designs – Commercialization Perspective Planar Reactor Design Planar Reactor Design Radiator-Type Design H 2 O CO 2 Methane formation CO 2 + 2H + + 8e - CH 4 + 2 H 2 O Photocatalyst CO 2 Chemical Products Structure H 2 O Formic acid formation CO 2 + 2H + + 2e - HCO 2 H CO 2 + e - CO 2 + e - - - CO 2 CO 2 Reflector 2H 2 O + 4h + 2H 2 O + 4h + O 2 + 4H + O 2 + 4H + Cross PN Nanostructure Section Metal Substrate Reactor Unit Solar-Thermal Design Cylindrical Reactor Design (Patent Pending) Glass Tube Products WBG Layer Porous Photocatalyst Tube Structure NBG Layer Glass Tube Reactor Array H 2 O Products CO 2 Solar Concentrator Prototype radiator-type solar reactor built using modular quartz tubing & mylar reflector (Tube unit: 0.5in diameter X 15 in long) PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Product(s) Detection by FTIR (Gas Phase) Fourier Transform Infrared Spectroscopy (FTIR) Continuous flow closed system CO 2 reforming reactor coupled to FTIR gas cell for real-time analysis PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
CO 2 Reforming using TiO 2 /Cu Photocatalyst Structure & UV Light CO 2 to CH 4 Conversion by TiO 2 /Cu Structure 1 9000 CO 2 concentration decreases, 0.9 8000 while methane increases CO 2 CH 4 0.8 7000 Reforming yield slows over CH 4 Production (ppmV) 0.7 6000 FTIR Absorbance time due to Cu oxidation and 0.6 5000 formation of graphitic carbon 0.5 4000 0.4 H 2 O 3000 0.3 Lamp Lamp 2000 0.2 Glass Reactor Glass Reactor 1000 0.1 Reflector Reflector 0 0 Photocatalyst Photocatalyst Tubing Tubing 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Structure Structure Pump Pump Time (hrs) Rubber Rubber Time evolution data measured by FTIR of gas composition inside a Tubing Tubing TiO 2 /copper photocatalytic reactor system under UVA radiation FTIR Gas Cell FTIR Gas Cell - 6W UVA bulb (340-400 nm) with intensity of ~8 mW/cm 2 ] Detector/ Detector/ IR Laser IR Laser Analyzer Analyzer - Atmospheric pressure & room temperature) PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Fuel Product(s) Selectivity through Multilayer Structures o Formaldehyde o PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Nano-Structures Grown by Solution Processing (a) TiO 2 nanorods on Ti ▼ Formic compound ▼ Formic compound ▼ ▼ substrates by anodization 3330 ppmV 25 µ l TiO 2 TiO 2 Absorbance Absorbance CO 2 CO 2 CH 4 CH 4 CO 2 CO 2 ▼ ▼ ▼ ▼ * * H 2 O H 2 O TiO 2 nanorods on Ti substrates by solvothermal Wavenumbers (cm -1 ) Wavenumbers (cm -1 ) FTIR spectrum of gas composition in photocatalytic reactor with TiO 2 nanorod on Ti substrate after UVA radiation of 168 hours (7 days) at 8 mW/cm 2 PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
TiO 2 Nano-Structures by Glancing Angle Deposition (GLAD) Various TiO 2 nanoporous films grown with glancing angle α = 95° PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Ion-assisted Deposition (IAD) of Thin-film Nanostructures Thin-film processing at Georgia Tech: • Process development for wide bandgap TiO 2 and narrow bandgap thin-films • Multilayer deposition/optimization • Investigation of “3D” nano-structures for improved light harvesting and catalytic properties PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
Glancing Angle Deposition IAD E-beam Section • GLAD is a thin film deposition technique that enables growth of porous, nano-structured films • Thin films grown by physical vapor deposition (PVD) with e- beam evaporation system • Substrate oriented so that flux arrives at substrate at highly oblique angles of incidence, determined by α and α tilt Typically α ~ 70 o or higher • Substrate can be rotated about axis, φ • • Use low-pressure PVD as atoms TiO 2 , Cd/ZnSe, etc. must travel in a linear trajectory and create are used as the e- shadow effect evaporation source materials Robbie & Brett, J. Vac. Sci. Technol. A 15, 1460 (1997) PhosphorTech Corporation – 3645 Kennesaw North Industrial Pkwy, Kennesaw, Ga 30144 www.phosphortech.com - (770) 745-5693 (phone) - (770) 828-0672 (Fax)
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