title: Photocatalytic synthesis of urea from in situ generated ammonia and carbon dioxide.
abstract: TiO(2) and Fe-titanate (different wt%) supported on zeolite were prepared by sol-gel and solid-state dispersion methods. The photocatalysts prepared were characterized by X-ray diffraction, scanning electron microscopy and ultraviolet (UV)-visible diffuse reflectance spectroscopy techniques. Photocatalytic reduction of nitrate in water and isopropanol/oxalic acid as hole scavengers are investigated in a batch reactor under UV illumination. The yield of urea increased notably when the catalysts were supported on zeolite. The Fe-titanate supported catalyst promotes the charge separation that contributes to an increase in selective formation of urea. The product formation is because of the high adsorption of in situ generated CO(2) and NH(3) over shape-selective property of the zeolite in the composite photocatalyst. The maximum yield of urea is found to be 18 ppm while 1% isopropanol containing solution over 10 wt% Fe-titanate/HZSM-5 photocatalyst was used.
authors.affiliation: Inorganic and Physical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad, India.
authors.forename: Basavaraju
authors.initials: B
authors.lastname: Srinivas
authors.forename: Valluri Durga
authors.initials: VD
authors.lastname: Kumari
authors.forename: Gullapelli
authors.initials: G
authors.lastname: Sadanandam
authors.forename: Chilumula
authors.initials: C
authors.lastname: Hymavathi
authors.forename: Machiraju
authors.initials: M
authors.lastname: Subrahmanyam
authors.forename: Bhudev Ranjan
authors.initials: BR
authors.lastname: De
mesh_terms: D019840:2-Propanol / Q000737:chemistry; D000641:Ammonia / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D002384:Catalysis; D008855:Microscopy, Electron, Scanning; D009566:Nitrates / Q000737:chemistry; D019815:Oxalic Acid / Q000737:chemistry; D055668:Photochemical Processes; D013056:Spectrophotometry, Ultraviolet; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D014508:Urea / Q000138:chemical synthesis*; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry
chemical_list: D009566:Nitrates; D014867:Water; D017641:Zeolites; D002245:Carbon Dioxide; C009495:titanium dioxide; D000641:Ammonia; D014508:Urea; D019815:Oxalic Acid; D014025:Titanium; D019840:2-Propanol