A visible-light-active photocatalyst was prepared by calcination of the hydrolysis product of tetrabutyl titanate with ammonia as precipitant. The photocatalyst was characterized by X-ray diffraction (XRD), UV-Vis dif...A visible-light-active photocatalyst was prepared by calcination of the hydrolysis product of tetrabutyl titanate with ammonia as precipitant. The photocatalyst was characterized by X-ray diffraction (XRD), UV-Vis diffuse reflection spectra (DRS), thermal gravimetric-differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM). The color of the photocatalyst was yellow and could absorb light wavelength under 550 nm as measured by DRS. The catalyst calcined at higher temperature will give lower absorbance for visible light. Structures of the sample were characterized mainly to be anatase by XRD except for the sample calcined at 700 ℃ which gave mixtures of anatase and rutile. TG-DTA results showed that temperature for anatase formation was 415 ℃. XPS results showed that doped-nitrogen was presented in the sample, they are important to show visible-light absorbency. The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants, the results showed that over 90% of phenol could be degraded under visible light using N/TiO2 as the catalyst after 4 hours reaction. Almost the same activity was found for the TiO2 photocatalyst calcined at different temperature under sunlight but activities were different when the treatment was under UV light.展开更多
为研究具有良好活性的低温选择性催化还原催化剂,针对目前Mn基材料低温选择性催化还原脱硝催化剂研究的局限性,以超氧自由基促进光催化为理论基础,N掺杂改性非金属为研究思路,采用溶胶凝胶法及过量浸渍法制备了N掺杂MnOx/TiO2催化剂,用...为研究具有良好活性的低温选择性催化还原催化剂,针对目前Mn基材料低温选择性催化还原脱硝催化剂研究的局限性,以超氧自由基促进光催化为理论基础,N掺杂改性非金属为研究思路,采用溶胶凝胶法及过量浸渍法制备了N掺杂MnOx/TiO2催化剂,用于锅炉烟气脱硝。提出了氧浓度、[NH3]/[NO]以及空速对脱硝效率的影响,结合X射线衍射表征,获得了N掺杂催化剂的反应工艺参数和相应的晶型变化特性。研究结果表明,N掺杂后,催化剂脱硝活性明显,并对催化剂N掺杂量、Mn负载量及催化剂煅烧温度进行了优化,并对优化结果进行分析。在此基础上,考察了含氧量,得出在O2浓度5%、[NH3]/[NO]为1.2时,空速28 000 h 1,反应温度180℃的条件下,掺N量为1%以及Mn负载量为5%的N掺杂MnOx/TiO2催化剂的脱硝活性稳定在90%左右。展开更多
基金Project(cstc2011jj A50008)supported by the Natural Science Foundation of Chongqing,ChinaProject(14ZB0025)supported by Education Department of Sichuan Province,China
文摘A visible-light-active photocatalyst was prepared by calcination of the hydrolysis product of tetrabutyl titanate with ammonia as precipitant. The photocatalyst was characterized by X-ray diffraction (XRD), UV-Vis diffuse reflection spectra (DRS), thermal gravimetric-differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM). The color of the photocatalyst was yellow and could absorb light wavelength under 550 nm as measured by DRS. The catalyst calcined at higher temperature will give lower absorbance for visible light. Structures of the sample were characterized mainly to be anatase by XRD except for the sample calcined at 700 ℃ which gave mixtures of anatase and rutile. TG-DTA results showed that temperature for anatase formation was 415 ℃. XPS results showed that doped-nitrogen was presented in the sample, they are important to show visible-light absorbency. The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants, the results showed that over 90% of phenol could be degraded under visible light using N/TiO2 as the catalyst after 4 hours reaction. Almost the same activity was found for the TiO2 photocatalyst calcined at different temperature under sunlight but activities were different when the treatment was under UV light.
文摘为研究具有良好活性的低温选择性催化还原催化剂,针对目前Mn基材料低温选择性催化还原脱硝催化剂研究的局限性,以超氧自由基促进光催化为理论基础,N掺杂改性非金属为研究思路,采用溶胶凝胶法及过量浸渍法制备了N掺杂MnOx/TiO2催化剂,用于锅炉烟气脱硝。提出了氧浓度、[NH3]/[NO]以及空速对脱硝效率的影响,结合X射线衍射表征,获得了N掺杂催化剂的反应工艺参数和相应的晶型变化特性。研究结果表明,N掺杂后,催化剂脱硝活性明显,并对催化剂N掺杂量、Mn负载量及催化剂煅烧温度进行了优化,并对优化结果进行分析。在此基础上,考察了含氧量,得出在O2浓度5%、[NH3]/[NO]为1.2时,空速28 000 h 1,反应温度180℃的条件下,掺N量为1%以及Mn负载量为5%的N掺杂MnOx/TiO2催化剂的脱硝活性稳定在90%左右。
