الفهرس 
Chapter one: IntroductionOnly 14 pages are availabe for public view
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Abstract
The First part: Solar-driven Photocatalyzed Hydrogen Production from Water cleavage using TiO2 nanocatalyst : Evaluation and Process Life Cycle Assessment
The second part includes: Synergetic effect of metal-doped GO and TiO2 on enhancing visible-light-driven photocatalytic hydrogen production from water splitting
The feasibility of solar-driven hydrogen generation from water cleavage is investigated using commercial TiO2 nanoparticles, and life cycle assessment (LCA) of the process is estimated. TiO2 is fully characterized. The maximum calculated photocatalytic rate of hydrogen over PC was 4.76 µmole/h under sunlight. It is obvious that kapp is highly dependent concentration of TiO2. The formation of p-n junction nanocomposits form precursors has been investigated. The synthesis of graphene oxide (GO) proceeds by oxidation of graphite and exfoliation by the simple sonication method. During sonication, the precursors of Co ([Ar] 3d7 4s2 ) or Ni ([Ar] 3d8 4s2) were added with proper mass. Then, titanium isopropoxide as a precursor of Titania is added with different ratios. TEM images showed the appearance of scattered Co and TiO2 nanoparticles in the sheet of GO. The XRD patterns proved the formation of GO and Titania. In addition, the elemental analysis showed the presence of cobalt, carbon, oxygen, and titanium in the sample. Interestingly, both p-NiO(GO)/n-TiO2 and p-CoO(GO)/n-TiO2 hetero-junctions nano materials enriched the photo-catalytic activity headed for water splitting nonetheless with different mechanisms. The p-NiO(GO)/n-TiO2 photocatalyst showed a higher hydrogen evolution rate than p-CoO(GO)/n-TiO2. The generated e/h pairs in the TiO2 part of the catalyst is kept through the effect of the electric field formed by the p-NiO/n-TiO2 heterojunction. While Co presence narrows the band gap and promotes both hydrogen and oxygen evolution reactions at the conduction and valence band of the prepared p-CoO/n-TiO2 heterojunction. Furthermore, the optimum ratio of GO:Ni:TiO2 in the hybrids was 10:1:2, while the higher TiO2 ratio would decrease the hydrogen production performance and photocatalytic activity. In contrast, the catalytic activity and the H2 production rate were increased by increasing the TiO2 ratio in the GO:Co:TiO2 nanocomposite catalyst and the highest performance was obtained at ratio of 10:1:5, respectively. The remarkably boosted photocatalytic performance under visible (solar) light may be mainly assigned to the synergetic effect of Ni/Co and GO supported TiO2.