High-Rate Solar Photocatalytic Conversion of CO2 and Water Vapor to Hydrocarbon Fuels

• Published in: Nano letters Vol. 9; no. 2; pp. 731 - 737
• Main Authors: Varghese, Oomman K, Paulose, Maggie, LaTempa, Thomas J, Grimes, Craig A
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.02.2009; Amer Chemical Soc
• Subjects: Carbon Dioxide - chemistry; Catalysis - radiation effects; Chemistry; Chemistry, Multidisciplinary; Chemistry, Physical; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Hydrocarbons - chemistry; Materials Science; Materials Science, Multidisciplinary; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanoscience & Nanotechnology; Nanotubes; Nanotubes - chemistry; Nitrogen - chemistry; Phase Transition - radiation effects; Photochemical Processes - radiation effects; Physical Sciences; Physics; Physics, Applied; Physics, Condensed Matter; Science & Technology; Science & Technology - Other Topics; Sunlight; Technology; Water - chemistry; X-Ray Diffraction; ROOM-TEMPERATURE; ZRO2; REDUCTION; METHANATION; H2O; MU-M; ADSORPTION; CARBON-DIOXIDE; TIO2 NANOTUBE ARRAYS; TITANIA; Methane; Reaction intermediates; Intermediate product; Reaction product; Carbon dioxide; Nanotubes; Hydrocarbons; Nanoparticles; Platinum; Steam; Illumination; Nitrogen additions; Carbon monoxide; Copper; Titanium oxide; Arrays; Nanostructured materials
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl803258p

Efficient solar conversion of carbon dioxide and water vapor to methane and other hydrocarbons is achieved using nitrogen-doped titania nanotube arrays, with a wall thickness low enough to facilitate effective carrier transfer to the adsorbing species, surface-loaded with nanodimensional islands of cocatalysts platinum and/or copper. All experiments are conducted in outdoor sunlight at University Park, PA. Intermediate reaction products, hydrogen and carbon monoxide, are also detected with their relative concentrations underlying hydrocarbon production rates and dependent upon the nature of the cocatalysts on the nanotube array surface. Using outdoor global AM 1.5 sunlight, 100 mW/cm2, a hydrocarbon production rate of 111 ppm cm−2 h−1, or ≈160 μL/(g h), is obtained when the nanotube array samples are loaded with both Cu and Pt nanoparticles. This rate of CO2 to hydrocarbon production obtained under outdoor sunlight is at least 20 times higher than previous published reports, which were conducted under laboratory conditions using UV illumination.