Performance and mechanism of CuO/CuZnAl hydrotalcites-ZnO for photocatalytic selective oxidation of gaseous methanol to methyl formate at ambient temperature

An efficient catalyst of CuPt/TiO2 for photocatalytic direct dehydrogenation of methanol to methyl formate at ambient temperature

CuPt alloy nanoparticles on TiO2 are highly effective for photocatalytic direct dehydrogenation of methanol to methyl formate at ambient temperature.

CuO Nanoparticle-Decorated TiO2-Nanotube Heterojunctions for Direct Synthesis of Methyl Formate via Photo-Oxidation of Methanol

Methyl formate is widely employed as one of the important organic intermediates in C1 chemistry and as an environmentally benign chemical in the emerging area of "green chemistry". We here study the catalytic effectiveness of CuO/TiO2-nanotube nanocomposites for the direct synthesis of methyl formate via methanol photo-oxidation in this paper. The CuO/TiO2-nanotube nanocomposites with 7% CuO weight loading give a promising photocatalytic performance (over 93.3% methanol conversion and 89.4% methyl formate selectivity) at 25 °C under 365 nm UV irradiation. The turnover frequency and the apparent quantum efficiency reach up to 22.9 molmethanol gcat -1 h-1 and 57.6% over 7% CuO/TiO2-nanotube, respectively, which is mainly because of the effective minimization of the recombination of photogenerated electrons and holes by the surface ultrasmall-sized CuO particles. Furthermore, these CuO/TiO2-nanotube nanocomposites exhibit excellent durability and robust nature during the catalytic processes of the methanol photo-oxidation to methyl formate. The experimental results demonstrate the promise of the robust CuO/TiO2 nanocomposites for efficient and green production of methyl formate, which may offer guidelines for the design of efficient catalysts for selective alcohol conversion to other valuable chemicals.

Photodegradation of volatile organic compounds catalyzed by MCr-LDHs and hybrid MO@MCr-LDHs (M = Co, Ni, Cu, Zn): the comparison of activity, kinetics and photocatalytic mechanism

The efficient removal of high-concentration volatile organic compounds (VOCs) has been a challenging task.

A low-temperature water–gas shift reaction catalyzed by hybrid NiO@NiCr-layered double hydroxides: catalytic property, kinetics and mechanism investigation

The realization of a high efficiency water gas shift reaction (WGSR) at low temperatures has always been a research hotspot and is difficult to achieve.

Copper on the inner surface of mesoporous TiO2 hollow spheres: a highly selective photocatalyst for partial oxidation of methanol to methyl formate

To raise the methyl formate (MF) selectivity at high methanol conversion is one of the most challenging topics for photocatalytic partial oxidation of methanol to MF.

Preparation and Enhanced Photocatalytic Properties of 3D Nanoarchitectural ZnO Hollow Spheres with Porous Shells

By using ginkgo leaves (GL) as template and Zn(CH₃COO)₂∙2H₂O as Zn source, a series of ZnO samples with special morphology were prepared via a template-assisted two-steps method without adding any other additives. The degradation of the dye MB was used to evaluate the photocatalytic property of the as-prepared samples. The results showed that when a proper amount of the template was used, a 3D nanoarchitectural ZnO hollow sphere with porous sphere shell assembled by well-distributed nanoparticles was obtained and its photocatalytic activity was much higher than that of ZnO nanoparticles. The special morphology of the sample was herein considered to be very helpful for highly efficient adsorption and activation of reactant molecules by multi-times adsorption-desorption-adsorption, efficient absorption of irradiation light by repeated absorption-reflection-absorption, and efficient separation of the photogenerated e⁻-h⁺ pairs. In addition, the formation of 3D structure of sample ZnO was also discussed.

Visible light-driven methanol dehydrogenation and conversion into 1,1-dimethoxymethane over a non-noble metal photocatalyst under acidic conditions

The dehydrogenation and conversion of methanol into 1,1-dimethoxymethane (DMM) was achieved over noble metal free photocatalyst CdS/Ni₂P under visible light.

New insight into the selective photocatalytic oxidation of RhB through a strategy of modulating radical generation

Rhodamine B (RhB) has often been used as a model pollutant, but its photocatalytic mechanism is still controversial. Herein, Ag NPs were sandwiched between CdS QDs and amorphous-TiO₂ (a-TiO₂) with the intent to build a CdS/Ag/a-TiO₂ catalyst with highly selective oxidation activity. When rhodamine B (RhB) was used as the model organic compound, the CdS/Ag/a-TiO₂ composite can not only modulate radical generation but also improve the conversion ratio of RhB to rhodamine 110 (Rh-110) to as high as 82% at 80 min during the visible-light irradiation. A series of the radical scavenging experiments revealed that CdS/Ag/a-TiO₂ composites could modulate the effects of hydroxyl radicals (·OH) and superoxide anion radicals (·O₂⁻) at different reaction stages so that the overoxidation of RhB and Rh-110 were repressed. Therefore, the transient state protection mechanism of selective oxidation of RhB was proposed to explain the reaction selectivity for Rh-110. Although the effects of both ·O₂⁻ and ·OH are important during the photocatalytic selective oxidation of RhB, it is shown that the selective oxidation of RhB would be performed when the effect of ·O₂⁻ is bigger than the ·OH, if not, RhB would be oxidized unselectively. Meanwhile, this may provide a new strategy for modulating radical generation in the photocatalysis of water phases.

A new photocatalytic mechanism of RhB was proposed according to the effect of reactive radical under different light irradiation.