Metal Oxides and Their Physico-Chemical Properties in Catalysis and Synthesis

Klabunde, Kenneth J.; Hoq, Mahbubul; Mousa, Faleh; Matsuhashi, Hiromi

doi:10.1016/b978-0-12-437105-7.50006-5

Cited by 3 publications

(3 citation statements)

References 94 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In choosing materials for study, MgO and CaO are very attractive since they are highly ionic and high melting, and it would be expected that samples of very small particle size might be stable and isolable. Furthermore, reactive surface sites on these oxides have been studied extensively, especially for MgO crystals and powders …”

Section: Classes Of Nanoparticlesmentioning

confidence: 99%

“…The microfaceted (111) surface of MgO is particularly reactive, , and steps, kinks, and point defects (ion vacancies and substitutions) are also important . Indeed, the unique catalytic properties of defective MgO surfaces also depend on a plethora of unusual coordination sites. ,− In summary, the remarkable properties of thermally activated polycrystalline MgO (and CaO) are well documented, ,,− and the types of surfaces produced are very dependent on preparative method. ,− …”

Section: Classes Of Nanoparticlesmentioning

confidence: 99%

See 1 more Smart Citation

Nanocrystals as Stoichiometric Reagents with Unique Surface Chemistry

et al. 1996

Self Cite

View full text Add to dashboard Cite

Nanocrystals of MgO and CaO have been prepared by a modified aerogel/hypercritical drying/dehydration method. For nanocrystalline MgO (AP-MgO) surface areas ranged from 250 to 500 m 2 /g, whereas for AP-CaO 100-160 m 2 /g. These materials have been compared with more conventional (CP) microcrystalline samples of lower surface area with regard to (1) morphology (AP-samples (autoclave preparation) are tiny polyhedral crystallites, while CP-samples (conventional preparation) are larger, hexagonal platelets and cubes);(2) residual surface OH (AP-samples have less acidic OH, which are more isolated from each other; (3) acid gas adsorption (AP-samples adsorb more SO 2 and CO 2 at low pressures and room temperature and prefer monodentate rather than bidentate adsorption modes, but at higher pressures CP-samples adsorb more SO 2 and HCl apparently due to the formation of more well ordered multilayers); (4) destructive adsorption of organophosphorus compounds and chlorocarbons (AP-samples are superior due to higher surface areas and higher surface reactivities), and (5) very thin layers of transition metal oxides on the MgO and CaO nanocrystals that significantly enhance destructive adsorption capacities to the point where [M x O y ]AP-MgO and [M x O y ]-AP-CaO become stoichiometric in reaction with CCl 4 . The data are conclusive that the nanocrystals are more reactive than the microcrystals, and this is mainly attributed to morphological differences, including defects. However, intrinsic electronic effects due purely to "smallness" cannot be ruled out.

show abstract

Section: Classes Of Nanoparticlesmentioning

confidence: 99%

Section: Classes Of Nanoparticlesmentioning

confidence: 99%

Nanocrystals as Stoichiometric Reagents with Unique Surface Chemistry

et al. 1996

Self Cite

View full text Add to dashboard Cite

show abstract

“…The diversity of research field connected to the chemistry of materials is significant for their applications in many areas including adsorption, catalysis, electrochemistry, and surface science. Nanoparticles [34], metal oxide, and mixed metal oxides [35][36][37][38] prepared by simple methods are useful catalysts. Research involving metal-organic frameworks [39,40], mesoporous silica [41][42][43], microporous or open-framework inorganic [44][45][46], and/or mesopore modified [47] materials has steadily increased following the widespread utility of aluminosilicate zeolites [48][49][50][51], titanosilicates [52,53], and aluminium phosphates [54,55].…”

Section: Materials For Catalysismentioning

confidence: 99%

Organocatalysis: Key Trends in Green Synthetic Chemistry, Challenges, Scope towards Heterogenization, and Importance from Research and Industrial Point of View

Shaikh

2014

Journal of Catalysts

View full text Add to dashboard Cite

This paper purports to review catalysis, particularly the organocatalysis and its origin, key trends, challenges, examples, scope, and importance. The definition of organocatalyst corresponds to a low molecular weight organic molecule which in stoichiometric amounts catalyzes a chemical reaction. In this review, the use of the termheterogenized organocatalystwill be exclusively confined to a catalytic system containing an organic molecule immobilized onto some sort of support material and is responsible for accelerating a chemical reaction. Firstly, a brief description of the field is provided putting it in a green and sustainable perspective of chemistry. Next, research findings on the use of organocatalysts on various inorganic supports including nano(porous)materials, nanoparticles, silica, and zeolite/zeolitic materials are scrutinized in brief. Then future scope, research directions, and academic and industrial applications will be outlined. A succinct account will summarize some of the research and developments in the field. This review tries to bring many outstanding researches together and shows the vitality of the organocatalysis through several aspects.

show abstract