The high cost and poor thermal durability of current lean nitrogen oxides (NOx) aftertreatment catalysts are two of the major barriers to widespread adoption of highly fuel-efficient diesel engines. We demonstrated the use of strontium-doped perovskite oxides as efficient platinum substitutes in diesel oxidation (DOC) and lean NOx trap (LNT) catalysts. The lanthanum-based perovskite catalysts coated on monolith substrates showed excellent activities for the NO oxidation reaction, a critical step that demands heavy usage of platinum in a current diesel aftertreatment system. Under realistic conditions, La(1-x)SrxCoO3 catalysts achieved higher NO-to-NO2 conversions than a commercial platinum-based DOC catalyst. Similarly, a La(0.9)Sr(0.1)MnO3-based LNT catalyst achieved NOx reduction performance comparable to that of a commercial platinum-based counterpart. The results show promise for a considerably lower-cost diesel exhaust treatment system.

The energy density of current lithium-ion batteries (LIBs) based on layered LiMO2 cathodes (M = Ni, Mn, Co: NMC; M = Ni, Co, Al: NCA) needs to be improved significantly in order to compete with internal combustion engines and allow for widespread implementation of electric vehicles (EVs). In this report, we show that atomic layer deposition (ALD) of titania (TiO2) and alumina (Al2O3) on Ni-rich FCG NMC and NCA active material particles could substantially improve LIB performance and allow for increased upper cutoff voltage (UCV) during charging, which delivers significantly increased specific energy utilization. Our results show that Al2O3 coating improved the NMC cycling performance by 40% and the NCA cycling performance by 34% at 1 C/−1 C with respectively 4.35 V and 4.4 V UCV in 2 Ah pouch cells. High resolution TEM/SAED structural characterization revealed that Al2O3 coatings prevented surface-initiated layered-to-spinel phase transitions in coated materials which were prevalent in uncoated materials. EIS confirmed that Al2O3-coated materials had significantly lower increase in the charge transfer component of impedance during cycling. The ability to mitigate degradation mechanisms for Ni-rich NMC and NCA illustrated in this report provides insight into a method to enable the performance of high-voltage LIBs.

SiO 2 nanotubes containing Ni nanoparticles were synthesized in a template nonionic surfactant water-in-oil (w/o) microemulsion, and were characterized by bright-field TEM. The highly defined cylindrical nanotube cavities had a uniform diameter of 12−13 nm; however cavity lengths were shown to be strongly dependent on aging time before silica precursor addition, hydrazine concentration, and synthesis temperature. Depending on synthesis conditions, Ni@SiO 2 (i.e., core@shell) nanotubes attained lengths up to 2 μm. A hypothesis is advanced that gas phases form and remain entrained in reverse-micelles, effecting both their elongation and also the exclusion of agglomerating silica species to outer micellar regions, thereby causing cavity formation. SiO 2 shell thicknesses could be controlled in the range of 5.1 to 12.4 nm by simple variation of the amount of silica precursor used. Furthermore, H 2 chemisorption measurements demonstrated 14−15% Ni dispersions, and N 2 physisorption analyses showed intraparticle pores on the order of 1 nm. These results confirm the accessibility of active metal sites via diffusion through the porous silica shells. Therefore the reported Ni@SiO 2 materials make an interesting addition to the developing class of M 1 @M 2 O x yolk−shell catalytic materials.

. -Strontium-doped perovskite oxides are efficient Pt substitutes in diesel oxidation and lean NOx trap catalysts. Under realistic conditions, a La0.9Sr0.1CoO3 catalyst achieves higher NO-to-NO2 conversion than a commercial Pt-based diesel oxidation catalyst. Similarly, a La0.9Sr0.1MnO3-based lean NOx trap catalyst achieves NO x reduction performance comparable to that of a commercial Pt-based counterpart. The results are promising for a considerably lower-cost diesel exhaust treatment system. -(KIM, C. H.; QI, G.; DAHLBERG, K.; LI*, W.; Sci.