CeOsupports were prepared by calcination or precipitation method and 5% MoO/CeOcatalysts were prepared by incipient-wetness impregnation method. The catalytic performance of the 5% MoO/CeOcatalysts toward sulfur-resis...CeOsupports were prepared by calcination or precipitation method and 5% MoO/CeOcatalysts were prepared by incipient-wetness impregnation method. The catalytic performance of the 5% MoO/CeOcatalysts toward sulfur-resistant methanation was investigated. The results showed that the Mo/Ce-1 catalysts with CeOsupport prepared by calcination method exhibited the best sulfur-resistant methanation activity and stability with CO conversion as high as 75% while the Mo/Ce-3 catalysts the poorest. The supports and catalysts were characterized by N-adsorption–desorption, temperature-programmed reduction（TPR）, X-ray diffraction（XRD）, Raman spectroscopy（RS） and scanning electron microscope（SEM）. The results indicated that the saturated monolayer loading MoOon Ce-3 support was lower than 5% and there were some crystalline MoOparticles on the surface of the Mo/Ce-3. The preparation method of CeOhad a big influence on the specific surface area, the crystalline of CeO, and the catalytic performance of the corresponding Mo-based catalyst for sulfur-resistant methanation.展开更多
Cerium‐based catalysts are very attractive for the catalytic abatement of nitrogen oxides(NOx)emitted from stationary sources.However,the main challenge is still achieving satisfactory catalytic activity in the low‐...Cerium‐based catalysts are very attractive for the catalytic abatement of nitrogen oxides(NOx)emitted from stationary sources.However,the main challenge is still achieving satisfactory catalytic activity in the low‐temperature range and tolerance to SO2 poisoning.In the present work,two series of Mo‐modified CeO_(2)catalysts were respectively obtained through a wet impregnation method(Mo‐CeO_(2))and a co‐precipitation method(MoCe‐cp),and the roles of the Mo species were systematically investigated.Activity tests showed that the Mo‐CeO_(2)catalyst displayed much higher NO conversion at low temperature and anti‐SO2 ability than MoCe‐cp.The optimal Mo‐CeO_(2)catalyst displayed over 80%NO elimination efficiency even at 150°C and remarkable SO2 resistance at 250°C(nearly no activity loss after 40 h test).The characterization results indicated that the introduced Mo species were highly dispersed on the Mo‐CeO_(2)catalyst surface,thereby providing more Brønsted acid sites and inhibiting the formation of stable adsorbed NOx species.These factors synergistically promote the selective catalytic reduction(SCR)reaction in accordance with the Eley‐Rideal(E‐R)reaction path on the Mo‐CeO_(2)catalyst.Additionally,the molybdenum surface could protect CeO_(2)from SO2 poisoning;thus,the reducibility of the Mo‐CeO_(2)catalyst declined slightly to an adequate level after sulfation.The results in this work indicate that surface modification with Mo species may be a simple method of developing highly efficient cerium‐based SCR catalysts with superior SO2 durability.展开更多
基金Financial supports from the National High Technology Research and Development Program of China(863 Project)(2015AA050504)the National Natural Science Foundation of China(21576203)
文摘CeOsupports were prepared by calcination or precipitation method and 5% MoO/CeOcatalysts were prepared by incipient-wetness impregnation method. The catalytic performance of the 5% MoO/CeOcatalysts toward sulfur-resistant methanation was investigated. The results showed that the Mo/Ce-1 catalysts with CeOsupport prepared by calcination method exhibited the best sulfur-resistant methanation activity and stability with CO conversion as high as 75% while the Mo/Ce-3 catalysts the poorest. The supports and catalysts were characterized by N-adsorption–desorption, temperature-programmed reduction（TPR）, X-ray diffraction（XRD）, Raman spectroscopy（RS） and scanning electron microscope（SEM）. The results indicated that the saturated monolayer loading MoOon Ce-3 support was lower than 5% and there were some crystalline MoOparticles on the surface of the Mo/Ce-3. The preparation method of CeOhad a big influence on the specific surface area, the crystalline of CeO, and the catalytic performance of the corresponding Mo-based catalyst for sulfur-resistant methanation.
文摘Cerium‐based catalysts are very attractive for the catalytic abatement of nitrogen oxides(NOx)emitted from stationary sources.However,the main challenge is still achieving satisfactory catalytic activity in the low‐temperature range and tolerance to SO2 poisoning.In the present work,two series of Mo‐modified CeO_(2)catalysts were respectively obtained through a wet impregnation method(Mo‐CeO_(2))and a co‐precipitation method(MoCe‐cp),and the roles of the Mo species were systematically investigated.Activity tests showed that the Mo‐CeO_(2)catalyst displayed much higher NO conversion at low temperature and anti‐SO2 ability than MoCe‐cp.The optimal Mo‐CeO_(2)catalyst displayed over 80%NO elimination efficiency even at 150°C and remarkable SO2 resistance at 250°C(nearly no activity loss after 40 h test).The characterization results indicated that the introduced Mo species were highly dispersed on the Mo‐CeO_(2)catalyst surface,thereby providing more Brønsted acid sites and inhibiting the formation of stable adsorbed NOx species.These factors synergistically promote the selective catalytic reduction(SCR)reaction in accordance with the Eley‐Rideal(E‐R)reaction path on the Mo‐CeO_(2)catalyst.Additionally,the molybdenum surface could protect CeO_(2)from SO2 poisoning;thus,the reducibility of the Mo‐CeO_(2)catalyst declined slightly to an adequate level after sulfation.The results in this work indicate that surface modification with Mo species may be a simple method of developing highly efficient cerium‐based SCR catalysts with superior SO2 durability.
