Tuning the crystallite size of monoclinic ZrO2 to reveal critical roles of surface defects on m–ZrO2 catalyst for direct synthesis of isobutene from syngas

Effect of the Zr promoter on precipitated iron-based catalysts for high-temperature Fischer–Tropsch synthesis of light olefins

“…With the further increase of zirconium content, the particle size of the FeMn5Zr2Na catalyst is steadily decreased to 11.5 nm and the dispersion of iron nanoparticles is increased, which will lead to an increase in the FTS activity. 24 However, when the Zr content is 10%, the surface enrichment of the Zr promoter covers a large number of active sites, which is consistent with the results as shown in…”

“…Therefore, the addition of zirconium leads to catalysts having a higher surface area and pore volume, which are more favorable to active phase dispersion. 14,24 With an increase of the zirconium content from 0 to 10%, the average pore diameter of the FeMnxZr catalysts decreases from 21.2 to 11.6 nm and that of the FeMnxZr2Na catalysts decreases from 28.2 to 15.8 nm due to the obvious structural promoter effect of zirconium. A smaller pore diameter in mesoporous catalysts results in higher iron oxide dispersion while an increase in pore diameter leads to larger iron particles.…”

The Role of Oxygen Vacancies in Phase Transition and the Optical Absorption Properties within Nanocrystalline ZrO2

“…As inferred from Figure 7 and Table 3 , the binding energy peak at 530.76 eV is assigned to lattice oxygen species (O Lattice ) on the surface. The moderate and higher energy peaks at 533.03 eV and 535.03 eV are attributed to chemically adsorbed oxygen species on the surface, denoted as O Defect and O OH , respectively [ 40 , 41 ]. The proportions for O Defect and O OH were found to be 58.48% and 9.94%, respectively, indicating a significant increase in the quantity of oxygen vacancies present on the surface of the sample after calcination.…”

Unsaturated Fe–Ov–Ti5c Structure with Enhanced C–H and C–C Bond Activation Ability for Selective Oxidation of Glycerol to Glycolic Acid

“…Generally, manufacturing defects through defect engineering, such as unsaturated sites, can effectively improve the oxidation performance of non-noble metal catalysts. − In recent reports, it has been proven that the introduction of Fe atoms as defect sites in the oxidation reaction could enhance the oxidation activity of C–H and C–C bonds. − For instance, Zhang et al reported that the unsaturated Fe sites in MIL-88B­(Fe) nanorods accelerated the activation of available O 2 , thus guaranteeing the C–H bond oxidation depth of formaldehyde . Ji et al found that the exposure of a single Fe site on the (100) surface of TiO 2 can enhance the electronic structure of the support, thus promoting the production of active • OH species and the cleavage of C–C bonds .…”