3D ordered meso-macroporous (3DOMM) Ce0.2Zr0.8O2 (CZO) was successfully synthesized by a combined method of evaporation-induced interfacial self-assembly (EISA) and colloidal crystal templates (CCT). The multifunctional catalysts of spinel-type Pd x Co3–x O4 nanoparticles (NPs) supported on 3DOMM CZO were fabricated by a gas bubbling assisted coprecipitation (GBCP) method. The relationship between nanostructure (hierarchical pore and spinel-type active phase) and activity during catalytic soot oxidation was studied by the techniques of SEM, TEM, XPS, H2-TPR, NO oxidation, soot-TPO, and so on. The 3DOMM structure with a larger surface area and total pore volume increases the amount of supported active sites and enhances the contact efficiency between reactants (soot, O2, and NO) and catalysts. Spinel-type Pd x Co3–x O4 (AB2O4) binary active sites by substitution for Co2+ (A site) with Pd2+ cations are beneficial for improving activation efficiency for gaseous reactants (NO and O2). The novel nanocatalysts of 3DOMM CZO-supported spinel-type Pd x Co3–x O4 NPs exhibited superb catalytic performance and strong nanostructure-dependent activity for soot oxidation under loose contact of soot with catalyst. For instance, the T 10, T 50, and T 90 values of 3DOMM PdCo2O4/CZO catalyst with the highest catalytic activity (TOF = 2.56 h–1) are only 313, 367, and 404 °C, respectively. The NO2-assisted catalytic mechanism for soot oxidation is studied and proposed by in situ Raman spectra, and the role of spinel-type PdCo2O4 binary active sites is revealed. 3DOMM Pd x Co3–x O4/CZO catalysts are decent systems for soot oxidation, and the easy preparation technology has the potential for application to catalysts with other element compositions.

The first catalytic asymmetric inverse-electron-demand (IED) oxa-Diels-Alder reaction of ortho-quinone methides, generated in situ from ortho-hydroxybenzyl alcohols, has been established. By selecting 3-methyl-2-vinylindoles as a class of competent dienophiles, this approach provides an efficient strategy to construct an enantioenriched chroman framework with three adjacent stereogenic centers in high yields and excellent stereoselectivities (up to 99 % yield, >95:5 d.r., 99.5:0.5 e.r.). The utilization of ortho-hydroxybenzyl alcohols as precursors of dienes and 3-methyl-2-vinylindoles as dienophiles, as well as the hydrogen-bonding activation mode of the substrates met the challenges of a catalytic asymmetric IED oxa-Diels-Alder reaction.

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A redox cycle process, in which CH 4 and air are periodically brought into contact with a solid oxide packed in a fixed-bed reactor, combined with the water-gas shift (WGS) reaction, is proposed for hydrogen production. The sole oxidant for partial oxidation of methane (POM) is found to be lattice oxygen instead of gaseous oxygen. A perovskite-type LaFeO 3 oxide was prepared by a sol-gel method and employed as an oxygen storage material in this process. The results indicate that, under appropriate reaction conditions, methane can be oxidized to CO and H 2 by the lattice oxygen of LaFeO 3 perovskite oxide with a selectivity higher than 95% and the consumed lattice oxygen can be replenished in a reoxidation procedure by a redox operation. It is suggested that the POM to H 2 /CO by using the lattice oxygen of the oxygen storage materials instead of gaseous oxygen should be possibly applicable. The LaFeO 3 perovskite oxide maintained relatively high catalytic activity and structural stability, while the carbonaceous deposits, which come from the dissociation of CH 4 in the pulse reaction, occurred due to the low migration rate of lattice oxygen from the bulk toward the surface. A new dissociation-oxidation mechanism for this POM without gaseous oxygen is proposed based on the transient responses of the products checked at different surface states via both pulse reaction and switch reaction over the LaFeO 3 catalyst. In the absence of gaseous-phase oxygen, the rate-determining step of methane conversion is the migration rate of lattice oxygen, but the process can be carried out in optimized cycles. The product distribution for POM over LaFeO 3 catalyst in the absence of gaseous oxygen was determined by the concentration of surface oxygen, which is relevant with the migration rate of lattice oxygen from the bulk toward the surface. This process of hydrogen production via selective oxidation of methane by lattice oxygen is better in avoiding the deep oxidation (to CO 2 ) and enhancing the selectivity. Therefore, this new route is superior to general POM in stability (resistance to carbonaceous deposition), safety (effectively avoiding accidental explosion), ease of operation and optimization, and low cost (making use of air not oxygen).