Search

Photocatalytic production of hydrogen peroxide (H2O2) has attracted much attentions as a promising method for sustainable solar fuel. Here, we demonstrate that trace water can drastically boost high-efficiency photocatalytic production of H2O2 with a record-high concentration of 113 mmol L−1 using alkali-assisted C3N4 as photocatalyst in water/alcohol mixture solvents. By electron paramagnetic resonance (EPR) measurement, the radical species generated during the photocatalytic process of H2O2 are identified. We propose alcohol is used to provide and stabilize · OOH radicals through hydrogen bond, while trace water could trigger photocatalytic production of H2O2 via providing and transferring indispensable free protons to completely consume · OOH radicals, which breaks the reaction balance of · OOH radical generation from alcohol. Thus · OOH radicals could be supplied by alcohol continuously to serve as a reservoir for high-efficiency production of H2O2. These results pave the way towards photocatalytic method on semiconductor catalysts as an outstanding approach for production of hydrogen peroxide.

The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N-heterocycles is a challenge. In this study, Ru2P/AC effectively promoted reversible transformations between unsaturated and saturated N-heterocycles affording yields of 98% and 99%, respectively. Moreover, a remarkable enhancement in the reusability of Ru2P/AC was observed compared with other Ru-based catalysts. According to density functional theory calculations, the superior performance of Ru2P/AC was ascribed to specific synergistic factors, namely geometric and electronic effects induced by P. P greatly reduced the large Ru-Ru ensembles and finely modified the electronic structures, leading to a low reaction barrier and high desorption ability of the catalyst, further boosting the hydrogenation and acceptorless dehydrogenation processes.

The selective hydrogenation of quinolines to 1,2,3,4-tetrahydroquinolines (py-THQ) and its derivatives has attracted a considerable amount of attention as they show great versatility in many pharmaceuticals, agrochemicals, and fine chemicals. Over the past few decades, great breakthroughs have been achieved in the controlled synthesis of efficient heterogeneous catalysts used for the selective hydrogenation of functionalized quinoline compounds, which allow one to correlate the structure-property relationships. In this review, we will summarize the recent significant progress achieved in this field covering the synthetic strategies, microstructural and chemical features, catalytic performance, and internal relationships. State-of-the-art noble metal-based single (Pd, Pt, Ru, Rh, Ir and Au) and bi/multi-metallic catalysts (RuCu, AuPd, and PdNi) are first introduced, followed by a summary of earth-abundant metal-based catalysts (Co, Fe, Ni, and Cu). Finally, the dehydrogenation of N -heterocycles is introduced to form a reversible hydrogenation/dehydrogenation system for H 2 storage, which can be employed in a liquid organic hydrogen system. Furthermore, the reaction mechanism and future research direction in these areas are also discussed. This review will deepen our understanding of the catalytic transformation of N -heterocycles and provide guidance for researchers on the rational design of catalysts.

In this work, the densities and refractive indices of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane with methoxybenzene, chlorobenzene, tert-butylbenzene and nitrobenzene at different temperatures T = (298.15, 303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure using a DMA4500/RXA170 combined system were measured. Excess molar volumes, isobaric thermal expansion, molar refractions, and the deviations in refractive indices have been estimated. These parameters have been used to understand the interactions in the mixtures qualitatively. The values of excess molar volume were fitted to Redlich–Kister equation to check the accuracy of experimental data.

Densities and refractive indices are investigated for four binary mixture systems of dimethylvinylethoxysilane with n-heptane, n-octane, n-nonane and n-decane at different temperatures (298.15, 303.15, 308.15, 313.15 and 318.15 K) and atmospheric pressure. From these experimental data, the excess molar volume, isobaric coefficient of thermal expansion, deviation in refractive index, molar refraction, and deviation in the molar refraction have been calculated. The computed quantities have been fitted with the Redlich–Kister equation to derive the coefficients and estimate the standard deviations. The values of the partial excess volume at infinite dilution were calculated using the coefficients of the Redlich–Kister smoothing equation. The effects of composition and temperature on these properties are discussed.