负载型磷酸氧钒低温脱硝催化剂的制备及其抗硫抗水性能
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摘要
针对目前低温脱硝催化剂抗硫抗水性较差的不足,以TiO_2为载体负载活性组分V_2O_5,利用磷酸调控表面酸性,制备了磷酸氧钒催化剂VPO/TiO_2,并实验研究了SO_2和水蒸气对其脱硝活性的影响。结果表明:控制P与V的摩尔比为1/5,活性组分(VPO)负载量为10%,焙烧温度为400℃时,催化剂脱硝性能最好,180～400℃温度范围内脱硝率高于98%;反应温度为200℃,烟气中SO_2体积分数为200×10~(-6)～800×10~(-6)和水蒸气体积分数为4%时,催化剂的活性无明显下降。添加磷酸能够促使催化剂表面生成VOPO_4、(VO)_2P_2O_7及V~(4+)/V~(5+)氧化还原电对,提高了催化剂的低温脱硝活性。磷酸可增强催化剂的表面酸性,减少了SO_2的表面吸附及其与活性组分的反应。另外,催化剂表面以介孔为主,可提高未被水分子占据的活性位点量,FT-IR图谱显示抗硫抗水测试后的VPO/TiO_2表面未发现有硫酸根生成,VPO/TiO_2表现出较强的抗SO_2和水蒸气毒化的性能。负载型磷酸氧钒催化剂具有较高的脱硝活性和较强的抗硫抗水性能。
In view of poor resistance to sulfur and water vapor for the low temperature DeNO_x catalyst, a type ofvanadium phosphate catalyst VPO/TiO_2 was prepared through doping active constituent V_2O_5 on TiO_2 andregulating the surface acidity with phosphoric acid in this study, and the effects of SO_2 and water vapor on itsDeNO_x activity were studied. The results showed that the best DeNO_x performance of this vanadium phosphatecatalyst was obtained at P/V molar ratio of 1/5, 10% active component(VPO) loading and the calcinationtemperature of 400 ℃, and the corresponding DeNO_x efficiency was above 98% at the temperature range of 180～400 ℃. The DeNO_x efficiency didn't decrease at reaction temperature of 200 ℃ when the volume fractions of SO_2 and water vapor were 200 × 10~(-6)～800 × 10~(-6) and 4%, respectively. The addition of phosphoric acid couldpromote the formation of VOPO_4,(VO)_2P_2O_7 and redox couples V~(4+)/V~(5+), which led to the improvement on the lowtemperature DeNO_x activity of the catalyst. Phosphoric acid addition could enhance the surface acidity ofvanadium-based catalyst, suppressed SO_2 adsorption on the catalyst surface and their reaction to activeconstituent. In addition, the catalyst surface mainly contained mesoporous structure, which caused the increaseof the amount of active sites unoccupied by the water molecules. The FT-IR spectra show that sulfate was notproduced on the surface of tested VPO/TiO_2 in the presence of SO_2 and water vapor. The VPO/TiO_2 catalystsshow a strong resistance to SO_2 and water vapor. Accordingly, the supported vanadium phosphate catalyst in thisstudy had a high catalytic activity and strong sulfur and water resistance.
In view of poor resistance to sulfur and water vapor for the low temperature DeNO_x catalyst, a type ofvanadium phosphate catalyst VPO/TiO_2 was prepared through doping active constituent V_2O_5 on TiO_2 andregulating the surface acidity with phosphoric acid in this study, and the effects of SO_2 and water vapor on itsDeNO_x activity were studied. The results showed that the best DeNO_x performance of this vanadium phosphatecatalyst was obtained at P/V molar ratio of 1/5, 10% active component(VPO) loading and the calcinationtemperature of 400 ℃, and the corresponding DeNO_x efficiency was above 98% at the temperature range of 180～400 ℃. The DeNO_x efficiency didn't decrease at reaction temperature of 200 ℃ when the volume fractions of SO_2 and water vapor were 200 × 10~(-6)～800 × 10~(-6) and 4%, respectively. The addition of phosphoric acid couldpromote the formation of VOPO_4,(VO)_2P_2O_7 and redox couples V~(4+)/V~(5+), which led to the improvement on the lowtemperature DeNO_x activity of the catalyst. Phosphoric acid addition could enhance the surface acidity ofvanadium-based catalyst, suppressed SO_2 adsorption on the catalyst surface and their reaction to activeconstituent. In addition, the catalyst surface mainly contained mesoporous structure, which caused the increaseof the amount of active sites unoccupied by the water molecules. The FT-IR spectra show that sulfate was notproduced on the surface of tested VPO/TiO_2 in the presence of SO_2 and water vapor. The VPO/TiO_2 catalystsshow a strong resistance to SO_2 and water vapor. Accordingly, the supported vanadium phosphate catalyst in thisstudy had a high catalytic activity and strong sulfur and water resistance.
引文
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[11]王明洪,王亮亮,刘俊,等.过渡金属对选择性催化还原脱硝CeO2@TiO2催化剂低温活性的促进作用[J].燃料化学学报,2017,45(4):497-504.
[12]沈伯雄,刘亭,杨婷婷,等.低温SCR脱硝催化剂过渡金属氧化物改性及硫中毒失活机制研究[J].环境科学,2009,30(8):2204-2209.
[13]JIANG B,YUE L,WU Z.Low-temperature selective catalytic reduction of NO on MnOx/TiO2prepared by different methods[J].Journal of Hazardous Materials,2009,162(2):1249-1254.
[14]WANG Z H,LIN F W,JING S D,et al.Ceria substrate-oxide composite as catalyst for highly efficient catalytic oxidation of NO by O2[J].Fuel,2016,166:352-360.
[15]ZHANG Y P,GUO W Q,Xu H T,et al.Characterization and activity of V2O5-CeO2/TiO2-ZrO2catalysts for NH3-selective catalytic reduction of NOx[J].Chinese Journal of Catalysis,2015,36(10):1701-1710.
[16]ZHANG J X,ZHANG S L,CAI W,et al.Effect of chromium oxide as active site over TiO2-PILC for selective catalytic oxidation of NO[J].Journal of Environmental Sciences,2013,25(12):2492-2497.
[17]PAVULESCU V I,GRANGE P,DELMON B.Catalytic removal of NO[J].Catalysis Today,1998,46:233-316.
[18]李小海,张舒乐,贾勇,等.H2O和SO2对Ce(1)Mn(3)Ti催化剂催化氧化NO性能的影响[J].燃料化学学报,2012,40(4):866-871.
[19]LI L D,SHEN Q,CHENG J,et al.Catalytic oxidation of NO over TiO2supported platinum clusters.Ⅱ:Mechanism study by situ FTIR spectra[J].Catalysis Today,2010,158(3/4):361-369.
[20]BOND G C.Vanadium oxide monolayer catalysts preparation characterization and catalytic activity[J].Applied Catalysis,1991,71(1):1-31.
[21]BUSCA G,CENTI G,TRIFIRO F,et al.Surface acidity of vanadyl pyrophosphate active phase in n-butane selective oxidation[J].Journal of Physical Chemistry,1986,90(7):1337-1344.
[22]姜烨,高翔,吴卫红.H2O和SO2对V2O5/TiO2催化剂选择性催化还原烟气脱硝性能的影响[J].中国电机工程学报,2013,33(20):28-33.
[23]段瑞瑞.V4+/V5+比值调变影响因素及其V4+和V5+转化的氧化还原速率与SCR脱硝活性[D].哈尔滨:哈尔滨工程大学,2014.
[24]FENG X Z,YAO Y,SU Q,et al.Vanadium pyrophosphate oxides:The role of preparation chemistry in determining renewable acrolein production from glycerol dehydration[J].Applied Catalysis B:Environmental,2015,164:31-39.
[25]曾炜,顾龙勤,徐俊峰,等.不同P与V比的Mo/VPO催化剂物相组成及其催化性能[J].工业催化,2014,22(8):595-598.
[26]TOPS?E N Y.Mechanism of the selective catalytic reduction of nitric oxide by ammonia elucidated by in situ on-line fourier transform infrared spectroscopy[J].Science,1994,265(5176):1217-1219.
[27]NOVA I,CIARDELLI C,TRONCONI E,et al.NH3-NO/NO2,chemistry over V-based catalysts and its role in the mechanism of the fast SCR reaction[J].Catalysis Today,2006,114(1):3-12.
[28]JIA Y,DU D Q,BAI J C,et al.Characterization and activity of N doped TiO2supported VPO catalysts for NO oxidation[J].Atmospheric Pollution Research,2015,6(2):184-190.
[29]LI L D,SHEN Q,CHENG J,et al.Catalytic oxidation of NO over TiO2supported platinum clusters.Ⅱ:Mechanism study by situ FTIR spectra[J].Catalysis Today,2010,158(3/4):361-369.
[30]GAN L,GUO F,YU J,et al.Improved low-temperature activity of V2O5-WO3/TiO2for denitration using different vanadium precursors[J].Catalysts,2016,6(2):25-40.
[31]LIN C H,BAI H.Surface acidity over vanadia/titania catalyst in the selective catalytic reduction for NO removal:In situ DRIFTS study[J].Applied Catalysis B:Environmental,2003,42(3):279-287.
[32]CHEN T,GUAN B,LIN H,et al.In situ DRIFTS study of the mechanism of low temperature selective catalytic reduction over manganese-iron oxides[J].Chinese Journal of Catalysis,2014,35(3):294-301.
[33]CHIRRANJIT S,SNEHA S,ANIRUDDHA M,et al.Synthesis,characterization of VPO catalyst dispersed on mesoporous silica surface and catalytic activity for cyclohexane oxidation reaction[J].Microporous and Mesoporous Materials,2016,223:121-128.
[34]GUO X Y,CAL B,WILLIAM H,et al.Effects of sulfate species on V2O5/TiO2SCR catalysts in coal and biomass-fired systems[J].Applied Catalysis B:Environmental,2009,92(1/2):30-40.
[35]CHEN J P,YANG R T.Selective catalytic reduction of NO with NH3on SO42-/TiO2superacid catalyst[J].Journal of Catalysis,1993,139(1):277-288.
[36]LU Q,PANG D,ZHANG C,et al.In situ IR studies of Co and Ce doped Mn/TiO2,catalyst for low-temperature selective catalytic reduction of NO with NH3[J].Applied Surface Science,2015,357(3):189-196.
[37]NIE J,WU X,MA Z,et al.Tailored temperature window of MnOx-CeO2,SCR catalyst by addition of acidic metal oxides[J].Chinese Journal of Catalysis,2014,35(8):1281-1288.
[38]CHEN T,GUAN B,LIN H,et al.In situ DRIFTS study of the mechanism of low temperature selective catalytic reduction over manganese-iron oxides[J].Chinese Journal of Catalysis,2014,35(3):294-301.
[2]环境保护部科技标准司.钢铁烧结、球团工业大气污染物排放标准:GB 28662-2012[S].北京:中国环境科学出版社,2012.
[3]HE Y Y,MICHAEL E F,ZHU M H,et al.Influence of catalyst synthesis method on selective catalytic reduction (SCR)of NO by NH3with V2O5-WO3/TiO2catalysts[J].Applied Catalysis B:Environmental,2016,193:141-150.
[4]张亚平,郭婉秋,王龙飞,等.V2O5/CeO2催化剂用于低温NH3-SCR的性能研究[J].催化学报,2015,36(10):1701-1710.
[5]ZANG S,ZHANG G,QIU W,et al.Resistance to SO2poisoning of V2O5/TiO2-PILC catalyst for the selective catalytic reduction of NO by NH3[J].Chinese Journal of Catalysis,2016,37(6):888-897.
[6]WAN Y,ZHAO W,YU T,et al.Ni-Mn bi-metal oxide catalysts for the low temperature SCR removal of NO with NH3[J].Applied Catalysis B:Environmental,2014,148-149(6):114-122.
[7]LIU J,LIU J,ZHAO Z H,et al.Synthesis of a chabazite-supported copper catalyst with full mesopores for selective catalytic reduction of nitrogen oxides at low temperature[J].Chinese Journal of Catalysis,2016,37(5):750-759.
[8]ROYER S,DUPREZ D,CAN F,et al.Perovskites as substitutes of noble metals for heterogeneous catalysis:Dream or reality[J].Chemical Reviews,2014,114(20):10292-10368.
[9]王瑞,归柯庭,梁辉.Ce的掺杂对负载型催化剂LaMnO/赤铁矿脱硝性能的影响[J].化工进展,2016,35(S2):192-199.
[10]QI K,XIE J,FANG D,et al.Performance enhancement mechanism of Mn-based catalysts prepared under N2for NOx removal:Evidence of the poor crystallization and oxidation of MnOx[J].Chinese Journal of Catalysis,2017,38(5):845-851.
[11]王明洪,王亮亮,刘俊,等.过渡金属对选择性催化还原脱硝CeO2@TiO2催化剂低温活性的促进作用[J].燃料化学学报,2017,45(4):497-504.
[12]沈伯雄,刘亭,杨婷婷,等.低温SCR脱硝催化剂过渡金属氧化物改性及硫中毒失活机制研究[J].环境科学,2009,30(8):2204-2209.
[13]JIANG B,YUE L,WU Z.Low-temperature selective catalytic reduction of NO on MnOx/TiO2prepared by different methods[J].Journal of Hazardous Materials,2009,162(2):1249-1254.
[14]WANG Z H,LIN F W,JING S D,et al.Ceria substrate-oxide composite as catalyst for highly efficient catalytic oxidation of NO by O2[J].Fuel,2016,166:352-360.
[15]ZHANG Y P,GUO W Q,Xu H T,et al.Characterization and activity of V2O5-CeO2/TiO2-ZrO2catalysts for NH3-selective catalytic reduction of NOx[J].Chinese Journal of Catalysis,2015,36(10):1701-1710.
[16]ZHANG J X,ZHANG S L,CAI W,et al.Effect of chromium oxide as active site over TiO2-PILC for selective catalytic oxidation of NO[J].Journal of Environmental Sciences,2013,25(12):2492-2497.
[17]PAVULESCU V I,GRANGE P,DELMON B.Catalytic removal of NO[J].Catalysis Today,1998,46:233-316.
[18]李小海,张舒乐,贾勇,等.H2O和SO2对Ce(1)Mn(3)Ti催化剂催化氧化NO性能的影响[J].燃料化学学报,2012,40(4):866-871.
[19]LI L D,SHEN Q,CHENG J,et al.Catalytic oxidation of NO over TiO2supported platinum clusters.Ⅱ:Mechanism study by situ FTIR spectra[J].Catalysis Today,2010,158(3/4):361-369.
[20]BOND G C.Vanadium oxide monolayer catalysts preparation characterization and catalytic activity[J].Applied Catalysis,1991,71(1):1-31.
[21]BUSCA G,CENTI G,TRIFIRO F,et al.Surface acidity of vanadyl pyrophosphate active phase in n-butane selective oxidation[J].Journal of Physical Chemistry,1986,90(7):1337-1344.
[22]姜烨,高翔,吴卫红.H2O和SO2对V2O5/TiO2催化剂选择性催化还原烟气脱硝性能的影响[J].中国电机工程学报,2013,33(20):28-33.
[23]段瑞瑞.V4+/V5+比值调变影响因素及其V4+和V5+转化的氧化还原速率与SCR脱硝活性[D].哈尔滨:哈尔滨工程大学,2014.
[24]FENG X Z,YAO Y,SU Q,et al.Vanadium pyrophosphate oxides:The role of preparation chemistry in determining renewable acrolein production from glycerol dehydration[J].Applied Catalysis B:Environmental,2015,164:31-39.
[25]曾炜,顾龙勤,徐俊峰,等.不同P与V比的Mo/VPO催化剂物相组成及其催化性能[J].工业催化,2014,22(8):595-598.
[26]TOPS?E N Y.Mechanism of the selective catalytic reduction of nitric oxide by ammonia elucidated by in situ on-line fourier transform infrared spectroscopy[J].Science,1994,265(5176):1217-1219.
[27]NOVA I,CIARDELLI C,TRONCONI E,et al.NH3-NO/NO2,chemistry over V-based catalysts and its role in the mechanism of the fast SCR reaction[J].Catalysis Today,2006,114(1):3-12.
[28]JIA Y,DU D Q,BAI J C,et al.Characterization and activity of N doped TiO2supported VPO catalysts for NO oxidation[J].Atmospheric Pollution Research,2015,6(2):184-190.
[29]LI L D,SHEN Q,CHENG J,et al.Catalytic oxidation of NO over TiO2supported platinum clusters.Ⅱ:Mechanism study by situ FTIR spectra[J].Catalysis Today,2010,158(3/4):361-369.
[30]GAN L,GUO F,YU J,et al.Improved low-temperature activity of V2O5-WO3/TiO2for denitration using different vanadium precursors[J].Catalysts,2016,6(2):25-40.
[31]LIN C H,BAI H.Surface acidity over vanadia/titania catalyst in the selective catalytic reduction for NO removal:In situ DRIFTS study[J].Applied Catalysis B:Environmental,2003,42(3):279-287.
[32]CHEN T,GUAN B,LIN H,et al.In situ DRIFTS study of the mechanism of low temperature selective catalytic reduction over manganese-iron oxides[J].Chinese Journal of Catalysis,2014,35(3):294-301.
[33]CHIRRANJIT S,SNEHA S,ANIRUDDHA M,et al.Synthesis,characterization of VPO catalyst dispersed on mesoporous silica surface and catalytic activity for cyclohexane oxidation reaction[J].Microporous and Mesoporous Materials,2016,223:121-128.
[34]GUO X Y,CAL B,WILLIAM H,et al.Effects of sulfate species on V2O5/TiO2SCR catalysts in coal and biomass-fired systems[J].Applied Catalysis B:Environmental,2009,92(1/2):30-40.
[35]CHEN J P,YANG R T.Selective catalytic reduction of NO with NH3on SO42-/TiO2superacid catalyst[J].Journal of Catalysis,1993,139(1):277-288.
[36]LU Q,PANG D,ZHANG C,et al.In situ IR studies of Co and Ce doped Mn/TiO2,catalyst for low-temperature selective catalytic reduction of NO with NH3[J].Applied Surface Science,2015,357(3):189-196.
[37]NIE J,WU X,MA Z,et al.Tailored temperature window of MnOx-CeO2,SCR catalyst by addition of acidic metal oxides[J].Chinese Journal of Catalysis,2014,35(8):1281-1288.
[38]CHEN T,GUAN B,LIN H,et al.In situ DRIFTS study of the mechanism of low temperature selective catalytic reduction over manganese-iron oxides[J].Chinese Journal of Catalysis,2014,35(3):294-301.