Experimental Study On Photocatalytic Reduction Of CO₂ By Metal Doped Nano-sized TiO₂

With the rapid development of the industry,environmental problem has become increasingly terrible,green environmental protection and energy conservation has gradually become a primary consideration of industrial development.At present,the emerging technology of the photocatalytic reduction of CO₂ plays an important role in the conversion and reuse of CO₂ gas,and can basically realize the goal of green environmental protection and energy conservation.The photocatalytic reduction of CO₂ into methanol,carbon monoxide,methane and other valuable organic matters under light irradiation conditions.In this paper,studying the effect of metal single-doped TiO₂ and bimetal co-doped TiO₂ on the photocatalytic reduction of CO₂ and intrinsic laws of metal doping modified TiO₂.The metal single-doped TiO₂ catalyst prepared by sol-gel method and high-temperature calcination method was characterized by TG-DTA,XRD,FT-IR,SEM,XPS and other means.Single-doped metals are Mn,Fe,Co,Ni,Cu,La,and the doped mass fraction of each metal is 0.3wt%,0.5wt%,0.7wt%,1.0wt%respectively.The experiments showed that the 1.0wt%Ni-TiO₂ photocatalyst calcined at 750?has smaller particle size,more valence state of metal load,distribution of uniform particle size,and Ni is stored in photocatalyst with+3valence and its corresponding mixed valence state.The experiment of the photocatalytic reduction of CO₂ was carried out.By measuring the yield of methanol,the metal single-doped TiO₂ photocatalyst with best photocatalytic activity was obtained.The results show that the methanol yield of 1.0wt%Ni-TiO₂is as high as 2.66?mol/(h?g_cata)under the conditions of catalyst input of 4 g/L,reaction temperature of 70?,CO₂ flow of 200 mL/min.The photocatalytic activity of Co-TiO₂ is the worst,the yield of methanol is 0.66?mol/(h?g_cata).The bimetal co-doped TiO₂ catalyst prepared by sol-gel method and high-temperature calcination method was characterized by TG-DTA,XRD,FT-IR,SEM,XPS and other means.Co-doped metals are Mn,Fe,Co,Ni,Cu,La,and the doped mass fraction of each bimetal is 0.2/0.8wt%,0.4/0.6wt%,0.6/0.2wt%,0.8/0.2wt%respectively.The experiments showed that the 0.4/0.6wt%Cu/Ni-TiO₂photocatalyst calcined at 700?has smaller particle size,distribution of uniform particle size,Cu and Ni is stored in photocatalyst with+2 valence,+3 valence respectively and its corresponding mixed valence state,characteristic peaks of the bimetal co-doped TiO₂ mixed valence state are more than the metal single-doped TiO₂,and the metal single-doped TiO₂ has smaller particle size and more uniform distribution of particle size than the bimetal co-doped TiO₂.The experiment of the photocatalytic reduction of CO₂ was carried out.By measuring the yield of methanol,the bimetal co-doped TiO₂ photocatalyst with best photocatalytic activity was obtained.The results show that the methanol yield of 0.4/0.6wt%Cu/Ni-TiO₂ is as high as 3.25?mol/(h?g_cata)under the conditions of catalyst input of 4 g/L,reaction temperature of 80?,CO₂ flow of 250 mL/min.The bimetal co-doped TiO₂ of Mn-doped is a rutile-based crystalline phase,which photocatalytic activity is poor.Figure 24 table 10 reference 72...