title: Design Strategies for CeO2-MoO3 Catalysts for DeNOx and Hg(0) Oxidation in the Presence of HCl: The Significance of the Surface Acid-Base Properties.
abstract: A series of CeMoOx catalysts with different surface Ce/Mo ratios was synthesized by a coprecipitation method via changing precipitation pH value. The surface basicity on selective catalytic reduction (SCR) catalysts (CeMoOx and VMo/Ti) was characterized and correlated to the durability and activity of catalyst for simultaneous elimination of NOx and Hg(0). The pH value in the preparation process affected the surface concentrations of Ce and Mo, the Brunauer-Emmett-Teller (BET) specific surface area, and the acid-base properties over the CeMoOx catalysts. The O 1s X-ray photoelectron spectroscopy (XPS) spectra and CO2-temperature programmed desorption (TPD) suggested that the surface basicity increased as the pH value increased. The existence of strong basic sites contributed to the deactivation effect of HCl over the VMo/Ti and CeMoOx catalysts prepared at pH = 12. For the CeMoOx catalysts prepared at pH = 9 and 6, the appearance of surface molybdena species replaced the surface -OH, and the existence of appropriate medium-strength basic sites contributed to their resistance to HCl poisoning in the SCR reaction. Moreover, these sites facilitated the adsorption and activation of HCl and enhanced Hg(0) oxidation. On the other hand, the inhibitory effect of NH3 on Hg(0) oxidation was correlated with the competitive adsorption of NH3 and Hg(0) on acidic surface sites. Therefore, acidic surface sites may play an important role in Hg(0) adsorption. The characterization and balance of basicity and acidity of an SCR catalyst is believed to be helpful in preventing deactivation by acid gas in the SCR reaction and simultaneous Hg(0) oxidation.
authors.affiliation: School of Environment and Natural Resources, Renmin University of China , Beijing 100872, China.|State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Huazhen
authors.initials: H
authors.lastname: Chang
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Qingru
authors.initials: Q
authors.lastname: Wu
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Mingguan
authors.initials: M
authors.lastname: Li
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Xiaoxu
authors.initials: X
authors.lastname: Sun
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University , Beijing 100084, China.|State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex , Beijing 100084, China.
authors.forename: Junhua
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University , Beijing 100084, China.|State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex , Beijing 100084, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Duan
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University , Beijing 100084, China.|State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex , Beijing 100084, China.
authors.forename: Jiming
authors.initials: J
authors.lastname: Hao
mesh_terms: D000327:Adsorption; D000641:Ammonia / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry
chemical_list: D010087:Oxides; D002245:Carbon Dioxide; C082290:molybdenum trioxide; D002563:Cerium; D009569:Nitric Oxide; C030583:ceric oxide; D000641:Ammonia; D008982:Molybdenum; D014025:Titanium; D008628:Mercury