Mononuclear gold species anchored on TS-1 framework as catalyst precursor for selective epoxidation of propylene

Electrocatalytic Reduction of N2 Using Metal-Doped Borophene

Ammonia synthesis is an essential process in chemistry and industry. However, it is limited by the lack of efficient catalysts and high energy costs. Developing highly efficient systems for ammonia synthesis is an important and long-standing challenge. In this paper, a large class of metal atoms (including 3d/4d transition metals and main group metals) anchored onto borophene have been studied as single atom catalysts for ammonia synthesis. After comprehensive computational screening and systematic evaluation, four candidates stand out. We predict that Mo, Mn, Tc, and Cr@BM-β₁₂ will have superior performance for catalytic reduction of N₂ to NH₃ with low limiting potentials of -0.26, -0.32, -0.38, and -0.48 V, respectively. Furthermore, we studied the activity of the competitive HER on M@BM-β₁₂. The results implied that the two materials Mo@BM-β₁₂ and Mn@BM-β₁₂ showed HER suppression. These properties exceed most currently reported nitrogen reduction reaction electrocatalysts. Our results suggest the possibility of efficient electrochemical reduction of N₂ to NH₃ in a lower energy process.

Recent Progress in Application of Molybdenum-Based Catalysts for Epoxidation of Alkenes

Epoxides are important industrial intermediates applied in a variety of industrial processes. During the production of epoxides, catalysts have played an irreplaceable and unique role. In this review, the historic progress of molybdenum-based catalysts in alkene epoxidation are covered and an outlook on future challenge discussed. Efficient catalysts are demonstrated including soluble molybdenum complexes, polyoxometalates catalysts, molybdenum-containing metal organic frameworks, silica supported molybdenum-based catalysts, polymer supported molybdenum-based catalysts, magnetic molybdenum-based catalysts, hierarchical molybdenum-based catalysts, graphene-based molybdenum containing catalysts, photocatalyzed epoxidation catalysts, and some other systems. The effects of different solvents and oxidants are discussed and the mechanisms of epoxidation are summarized. The challenges and perspectives to further enhance the catalytic performances in alkenes epoxidation are presented.

Gas phase selective propylene epoxidation over La2O3-supported cubic silver nanoparticles

It is shown that the Ag nanocube/La₂O₃ interface catalyses gas phase oxidation of propylene to propylene oxide cooperatively with enhanced selectivity and conversion. Dioxygen is preferentially activated and dissociated by La₂O₃(001) and the active atomic oxygen over the Ag(100) facet leads to selective propylene epoxidation.

Seed-assisted synthesis of TS-1 crystals containing Al with high catalytic performances in cyclohexanone ammoximation

In this study, titanium silicalite (TS-1) crystals containing Al were synthesized using aluminosilicate MFI zeolites as seeds in a tetrapropylammonium bromide (TPAB)–ethanolamine (EA) system. The TS-1 containing Al possessed large size, large L_b value and higher catalytic activity in cyclohexanone ammoximation. Larger L_b value would endow the TS-1 crystals with better mechanical strength and erosion resistance. The introduction of an Al atom into the TS-1 crystals resulted in the production of more acid sites and a bit strong Brönsted acid sites; these acid sites were more favorable to the catalytic performances in cyclohexanone ammoximation.

Using aluminosilicate zeolites seeds, Al atoms are introduced into the TS-1 crystals, resulting in high L_bvalue and more acid sites, which improve the catalytic activity in cyclohexanone ammoximation.