摘要
采用溶胶凝胶法制备了Fe_(2)O_(3)/TiO_(2)催化剂,通过BET,XRD,XPS和XRF等对催化剂物化性质进行表征,并利用固定床反应系统考察了该催化剂对H_(2)S选择性催化氧化反应的活性。结果表明,当Fe_(2)O_(3)负载量低于15%时,随着负载量增大,催化剂比表面积逐渐增大,Fe_(2)O_(3)以高度分散态或非晶体形态均匀存在于催化剂体相中;而继续增大Fe_(2)O_(3)负载量到20%,催化剂比表面积下降,催化剂内Fe_(2)O_(3)以晶体形式存在并会堵塞催化剂表面的孔结构。随着负载量的增加,Fe_(2)O_(3)/TiO_(2)的H_(2)S转化率和产硫率先增加后减小,而硫选择性不断减小,15%Fe_(2)O_(3)/TiO_(2)催化剂具有最佳的催化活性,在反应温度180℃、O_(2)/H_(2)S物质的量比为0.5的条件下,催化剂的H_(2)S转化率,硫选择性和产硫率分别为96.57%,95.88%和92.60%。反应温度和O_(2)/H_(2)S物质的量比对催化剂催化活性有较大影响。随着反应温度升高,催化剂的H_(2)S转化率先增大后减小,硫选择性和产硫率则不断减小;O_(2)/H_(2)S物质的量比增加,H_(2)S转化率不断升高,硫选择性则逐渐下降,产硫率具有先增加后降低的趋势,在O_(2)/H_(2)S物质的量比为0.5时产硫率最大。反应后催化剂表征分析表明,Fe_(2)O_(3)/TiO_(2)催化剂H_(2)S催化氧化的主要产物是单质硫和硫酸铁。此外,提出了Fe_(2)O_(3)/TiO_(2)催化剂可能的H_(2)S选择性催化氧化机理,其中Fe^(3+)是主要的活性组分,在H_(2)S选择性催化氧化反应中起主要作用,硫酸铁的生成和单质硫的沉积为催化剂失活的主要原因。
Fe_(2)O_(3)/TiO_(2)catalysts were prepared by sol-gel method.The physicochemical properties of catalysts were characterized by BET,XRD and XRF,and the activity of catalysts for the selective catalytic oxidation of H_(2)S was investigated by the fixed-bed reaction system.The results show that the specific surface area of the catalyst gradually increases with the increase of loading,and the Fe_(2)O_(3)exists uniformly in the catalyst phase in highly dispersed or amorphous form when the Fe_(2)O_(3)loading is less than 15%.When the Fe_(2)O_(3)loading continues to increase to 20%,the specific surface area of the catalysts decreases,the Fe_(2)O_(3)exists in the form of crystal and blocks the pore structure of the catalyst surface.With the increase of loading,the H_(2)S conversion and sulfur yield of Fe_(2)O_(3)/TiO_(2)increase at first and then decrease,while the sulfur selectivity decreases,the 15%Fe_(2)O_(3)/TiO_(2)catalysts perform well under the conditions of reaction temperature 180℃and the O_(2)/H_(2)S molar ratio 0.5.The H_(2)S conversion rate,sulfur selectivity and sulfur yield are 96.57%,95.88%and 92.60%,respectively.The reaction temperature and the molar ratio of O_(2)/H_(2)S have great influence on the activity of the catalysts.With the increase of reaction temperature,the H_(2)S conversion rate increases at first and then decreases,while the sulfur selectivity and sulfur yield decrease continuously.With the increase of O_(2)/H_(2)S molar ratio,the H_(2)S conversion rate increases and the sulfur selectivity decreases gradually,and the sulfur yield increases at first and then decreases,and the sulfur yield is the highest when the O_(2)/H_(2)S molar ratio is 0.5.The analysis of spent catalysts show that elemental sulfur and sulfate are the main product of the catalytic oxidation of H_(2)S.In addition,the possible catalytic oxidation mechanism of H_(2)S on the Fe_(2)O_(3)/TiO_(2)catalysts is proposed,in which Fe^(3+)is the main active component and plays a major role in the selective catalytic oxidation of H_
作者
邢向文
张肖阳
汤吉昀
王欣欣
崔琳
董勇
XING Xiangwen;ZHANG Xiaoyang;TANG Jiyun;WANG Xinxin;CUI Lin;DONG Yong(National Engineering Laboratory for Coal-fired pollutants Emission Reduction,Shandong University,Jinan 250061,China;Changji University,Changji 831100,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2021年第S02期1088-1095,共8页
Journal of China Coal Society
基金
国家自然科学基金资助项目(51976108)
昌吉学院教科研资助项目(21KY007)
