Thermodynamic, achievable, and realistic efficiency limits of solar-driven electrochemical conversion of water and carbon dioxide to fuels are investigated as functions of light-absorber composition and configuration, and catalyst composition. The maximum thermodynamic efficiency at 1-sun illumination for adiabatic electrochemical synthesis of various solar fuels is in the range of 32-42%. Sing...

Ab-initio methods for computing stationary molecular states and radiationless transition probabilities between nonstationary states are discussed. The expansion methods, the molecular Hamiltonians, the adiabatic and dia-batic representations, and the symmetry properties are briefly discussed. As an example, nonadiabatic effects in the V-N spectrum of C2H4 and corresponding V-R, · radiationless ...

The CO sensing properties of a micro thermoelectric gas sensor (micro-TGS) with a double AuPtPd/SnO₂ and Pt/α-Al₂O₃ catalyst were investigated. While several nanometer sized Pt and Pd particles were uniformly dispersed on SnO₂, the Au particles were aggregated as particles measuring >10 nm in diameter. In situ diffuse reflectance Fourier transform Infrared spectroscopy (DRIFT) analysis of the c...

bis(indenyl)zirconium dichloride as a catalyst was synthesized using a modified method at the room temperature. polymerization of ethylene and copolymerization of ethylene and propylene were carried out by this metallocene catalyst. ethylene propylene (p/e) feed ratios of 0.25, 0.5, 1, and 2 were employed into the copolymerization systems. copolymerization conditions like cocatalyst/catalyst ra...

The potential energy surface for the reaction of C(Pj) with ethylene, C2H4(XAg), has been investigated using the G2M method. Structures of the stationary points and transition states for various isomerization and dissociation pathways of triplet C3H4 have been studied. The results show that at the initial step of the C(Pj) + C2H4(XAg) reaction carbon atom attacks the π-orbital of the C2H4 molec...

The adsorption of ethylene molecule on neutral, anionic and cationic gold clusters consisting of up to 10 atoms has been investigated using density-functional theory. It is demonstrated that C2H4 can be adsorbed on small gold clusters in two different configurations, corresponding to the πand di-σ -bonded species. Adsorption in the π-bonded mode dominates over the di-σ mode over all considered ...

The metal-catalyzed polymerization of simple olefins, such as ethylene and propylene, has been one of the transformational discoveries in chemistry of the 20th century. It is difficult to imagine today’s civilization without ubiquitous plastics, such as polyethylene and related polymers. Although often attributed to Karl Ziegler and Giulio Natta, the winners of the 1963 Nobel Prize in Chemistry...

A solid Ca/Al composite oxide-based alkaline catalyst containing Ca(12)Al(14)O(33) and CaO was prepared by chemical synthesis and thermal activation from sodium aluminate solution and calcium hydroxide emulsion. The effect of calcination temperatures ranging from 120 °C to 1000 °C on activity of the catalyst was investigated. The catalyst calcined at 600 °C showed the highest activity with >94%...

KF/Al2O3 as a green and efficient catalyst has been used for the synthesis of mono and bis pyrimidine derivatives via three-component reaction of amidines, malononitrile, and aldehydes in EtOH at reflux. The great advantage of this catalyst is the ease of handling. KF/Al2O3 can be used and removed by filtration, avoid cu...

Dehydroaromatization of methane (DHAM) under non oxidative condition was studied over tungsten loaded HZSM-5 catalysts to produce aromatic hydrocarbons. The catalysts were prepared by impregnation method using different conditions: in neutral and acidified solution. The activity of W/HZSM-5 prepared by neutral solution and W-H2SO4/HZSM-5 prepared in acidified condition were compared. The result...