A promising approach for chemical energy storage from fluctuating renewable electricity is methanol synthesis from CO2 and hydrogen in a slurry reactor concept, due to efficient heat storage and easy reactor control. In combination with a promising In2O3/ZrO2 catalyst and mineral oil as carrier liquid, efficient methanol production under a wide range of changing process conditions is shown for the first time. A maximum methanol productivity of 2.1 gMeOHgIn−1h−1 and multiple recycling stability of the catalyst and the carrier liquid was achieved, showing no significant decrease in methanol yields.

In this study, the performance of an In2O3/ZrO2 catalyst for hydrogenation of CO2 to methanol is reported in presence of typical impurities of industrial CO2 feed gas streams. Experiments were...

photocatalysis is of great potential for targeted applications.Due to their unique chemical, electrical, magnetic, mechanical, and optical properties and their catalytic activity, zinc oxide (ZnO) and especially ZnO nanoparticles have received considerable attention in both application fields, solar energy conversion, and catalysis. ZnO is an n-type semiconductor with a wide energy band (3.37 eV) and a high bond energy (60 meV). [1,2] It offers a wide range of properties depending on morphology, size, orientation, and density of the crystals. [3] A good electron mobility, a large volume to surface area ratio, a high UV absorption, and a long life-span are advantageous when used as a photocatalyst in UV-light. [4] The catalytic activity in different model reactions has been examined in dependence on morphology, size and shape, and pH. [3,[5][6][7] As the ZnO properties depend on the structure, numerous nanoparticle synthesis routes have been developed to create different shapes of ZnO structures such as 1D, 2D, and 3D structures including nanorods, nanoneedles, and nanoflowers. [8][9][10][11] A powerful technique to control the morphology is the use of surface-modifying substances, in particular macromole cules. [1] A number of studies have investigated various polymers such as polymethacrylic acid, polyethylene oxide (PEO) and PEO containing copolymers. [11][12][13][14][15] The application of polyethylene oxide-block-polymethacrylic acid (PEO-b-PMAA) copolymers as surface modifiers for ZnO has been thoroughly examined. [16] The photocatalytic activity and selectivity of novel binary and ternary composite nanostructures from polyethylene oxide-stabilized zinc oxide (PEO-ZnO) with and without polyoxometalate (H 4 [Si(W 3 O 10 ) 4 ], POM) are determined in aqueous solution under UV-light. Mono-and di-COOH-end-functionalized PEO polymers are used as surface modifiers, influencing the morphology and stability of the ZnO nanoparticles being synthesized in water. POM acts as an additional versatile photocatalytically active building block resulting in a ternary hybrid structure with tunable photocatalytic activity. Catalytic selectivity is demonstrated by studying photocatalytic dye degradations as model reactions, where the chemical backbone of the dyes and their charge turn out to be the basis for the selectivity. All samples are characterized with dynamic light scattering, transmission electron microscopy, scanning electron microscopy, light microscopy, and ζ-potential measurements. With the functionalized PEOs, large ZnO clusters consisting of leaves are formed while 2-[2-(2-methoxyethoxy) ethoxy] acetic acid (TODA) yields ZnO flower-like structures.

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It is desirable to reduce the reliance on fossil fuels and to develop alternative methods to yield valuable chemicals. CO2 hydrogenation to methanol is a promising approach, where In2O3/ZrO2 catalysts have attracted increasing attention due to their high selectivity and stability. However, the activity of indium-based catalysts is very susceptible to the preparation method, which is typically wet impregnation. Here, we explore a laser-based synthesis route to prepare InO x /ZrO2 catalysts of varying indium size and load. The respective particle sizes were either adjusted by in situ fragmentation with a more (ns-VIS-laser) or less (ns-IR-laser) efficient laser wavelength or by using micromolar concentrations of phosphate as an electrostatic stabilizer. The InO x colloids were subsequently deposited onto ZrO2 Our results demonstrate that the pulsed laser ablation with ns-IR-laser pulses yielded larger ∼45 nm crystalline cuboid InO x supported on zirconia. The frequency-doubled ns-VIS-pulses on the other hand caused an augmented in situ fragmentation during ablation, which led to catalysts with spherical ∼14 nm InO x particles with a significantly higher degree of amorphousness. Further size quenching and increased amorphous content of the InO x nanoparticles were observed when micromolar concentrations of phosphates were additionally present during ablation. After supporting the InO x nanoparticles onto ZrO2, the laser-generated catalysts were found to perform equally well as their wet-chemically prepared counterparts for methanol synthesis in a slurry phase, although crystalline In species performed slightly better in the catalytic reaction. In conclusion, in situ fragmentation does not only provide opportunities for independent studies of size and composition but also ripening control and structural modifications such as amorphization.