Promoted NH_(3)-SCR activity and hydrothermal stability of Cu-SSZ-50 catalyst synthesized by one-pot method

Nitrogen oxide(NO_(x))is one of the most critical contaminants in the air,and the control of NO_(x)emission from diesel vehicles is very important.Cu-based small-pore zeolites have already been applied for NO_(x)abatement on diesel vehicles.Among the small-pore zeolites,Cu-SSZ-50 catalysts with good NH_(3)-SCR catalytic activity were believed to have potential for application.In this study,a one-pot synthesis method for Cu-SSZ-50 catalysts was developed for the first time,using the co-templates of Cu-TEPA and 2,6-dimethyl-N-methylpyridinium hydroxide.In this synthesis method,Cu-SSZ-50 with various Cu contents can be obtained by adjusting the amount of Cu-TEPA without the need for a further after-treatment process.The addition of Cu-TEPA affected the framework atoms and Cu species,and a lower Si/Al ratio and more SCR active Cu species were obtained.The synthesized catalyst with a Cu/Al ratio of 0.40 exhibited over 90%NO_(x)conversion between 200℃and 450℃for the selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR).Meanwhile,over 80%NO_(x)conversion could be obtained from 250℃to 450℃after hydrothermal aging at 750℃for 16 h.In addition,both L-H and E-R mechanisms were proven to exist for the one-pot-synthesized Cu-SSZ-50 by in situ DRIFTS experiments.The simple synthesis procedure,excellent catalytic activity and hydrothermal stability brighten the prospects for the application of Cu-SSZ-50.

Influence of boron on ferrite formation in copper-added spheroidal graphite cast iron

This paper reviews the original work of the authors published recently,describing the influence of B on the matrix of the Cuadded spheroidal graphite cast iron.The effect of Cu has been corrected as a ferrite formation promoter in the matrix of the grey cast iron by the usage of high-purity material.Also,this paper focuses on the ferrite formation and the observation of the Cu distribution in the B-added and B-free Cu-containing spheroidal graphite cast iron.The Cu film on the spheroidal graphite can be successfully observed in the B-free sample using a special etching method.However,in the B-added sample,no Cu film could be found,while the secondary graphite was formed on the surface of the spheroidal graphite.The interaction between B and Cu is stressed as a peculiar phenomenon by the employment of a contrast experiment of B and Mn.The heat treatment could make Cu precipitate more significantly in the eutectic cells and in the matrix in the form of large Cu particles because of the limited solubility of Cu.

Tremendous enhancement of magnetic performance for Sm(CoFeCuZr)z magnet based on multiscale copper redistribution

Microstructure and magnetic properties were studied for the commercial Sm(Co FeCuZr)_(z) magnets before and after post annealing treatment.The results show that the phases composition and orientation of the magnet do not change after post annealing treatment,but the substantial redistribution of Cu element within multiscale(the microscale crystal grain and the nanoscale cellular structure) is observed simultaneously.In detail,along with the Cu redistribution,the thickness of the Cu-rich Sm(Co,Cu)_(5) cell boundary becomes thinner,and the Cu concentration in the boundary increases sharply.The pinning field of domain walls and corresponding coercivity increase remarkably with slight remanence and maximum energy product loss,and the overall magnetic performance of(BH)_(max)(MGOe)+H_(Cj)(kOe)increases by 54.3% as a result.Moreover,the thermal stability of the magnet improves as well.On the other hand,Cu-lean phenomenon was observed along the grain boundary region,triggering to magnetic domain reversal process and slightly undermining the squareness of the demagnetization curve of the magnet.

Time effects of rice straw and engineered bacteria on reduction of exogenous Cu mobility in three typical Chinese soils

Globally,copper(Cu)accumulation in soils is a major environmental concern.Agricultural organic waste and some bacterial species can readily absorb metals in an eco-friendly manner,and thus are commonly used in metal-contaminated soil remediation.This study investigates the change in Cu fractions during the aging process and the time effects of rice straw(RS)and engineered bacteria(EB)(Pseudomonas putida X4/pIME)on reduction of Cu mobility.Three typical Chinese soils(red,cinnamon,and black soils)were incubated with RS or RS+EB in the presence of exogenous Cu for 24 months.The soil physicochemical properties,reactive soil components,Cu fractions,and Cu mobility were determined over time.The Cu mobility factor(MF)values were the lowest in the black soil(6.4-9.2)because of its high organic carbon and clay contents.The additions of both RS and RS+EB accelerated Cu stabilization during the aging process in all three soils.The Cu MF values decreased with time during the initial 20 months;however,the MF values increased thereafter in all soils,which might be due to the reduction of humic substances and amorphous iron oxides and the increase in iron oxides complexed on the organic matter.The reduction rates of Cu MF were similar after 16,24,and more than 24 months in the red,cinnamon,and black soils,respectively,indicating that RS and RS+EB could limit Cu mobility at different times in various soils.The RS treatment showed the greatest efficiency in reducing Cu mobility in the red,cinnamon,and black soils after 12,12,and 8 months of incubation,respectively.The RS+EB treatment was more efficient than the RS treatment in the red soil during the initial 8 months of the incubation period.Our study provides theoretical support for Cu risk assessments and RS supplementation for Cu remediation in different soils.