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Following nanoarchitectural approach, mesoporous halloysite nanotubes with internal surface composed of alumina were loaded with 5-6 nm RuCo nanoparticles by sequential loading/ reduction procedure. Ruthenium nanoclusters were loaded inside clay tube by microwaveassisted method followed by cobalt ions electrostatic attraction to ruthenium during wetness impregnation step. Developed nanoreactors with bimetallic RuCo nanoparticles were investigated as catalysts for the Fischer-Tropsch process. The catalyst with 14.3 wt.% of Co and 0.15 wt.% of Ru showed high activity (CO conversion reached 24.6%), low selectivity to methane (11.9%), CO2 (0.3%), selectivity to C5+ hydrocarbons of 79.1% and chain growth index (α) = 0.853. Proposed nanoreactors showed better selectivity to target products combined with high activity in comparison to the similar bimetallic systems supported on synthetic porous materials. It was shown that reducing agent (NaBH4 or H2) used to obtain Ru nanoclusters at first synthesis step played a very important role in the reducibility and selectivity of resulting RuCo catalysts. [ABSTRACT FROM AUTHOR]

A nanoarchitectural approach for synthesis of highly crystalline zeolites based on natural aluminosilicate nanotubes with adjustable silica to alumina ratio has been developed. A double template technique was proposed for synthesis of zeolite microcrystals with geometric morphology defined by the initial aluminosilicate nanotubes (halloysite). Remarkable and unique zeolite microcrystal shapes (submicron spheres, pompon-like systems and coffin-shaped prisms) possessing different internal structures (sodalite, analcime, mordenite, mordenite framework inverted) were obtained from halloysite by hydrothermal method. Halloysite Si/Al adjustments (acid etching, addition of extra silica or alumina) significantly affected crystalline structure and morphology of the obtained materials, while changing organic templates did not have a considerable effect. [Display omitted] • A novel approach for zeolites synthesis from aluminosilicate nanotubes was proposed. • Zeolites morphology is defined by the initial aluminosilicate nanotubes. • SOD, ANA, MOR, and MFI microstructures were synthesized from natural nanoclay. [ABSTRACT FROM AUTHOR]

Hydrogenation of CO2 relative to valuable chemical compounds such as methanol or dimethyl ether (DME) is an attractive route for reducing CO2 emissions in the atmosphere. In the present work, the hydrogenation of CO2 into DME over CuO-In2O3, supported on halloysite nanotubes (HNT) was investigated in the temperature range 200–300 °C at 40 atm. HNT appears to be novel promising support for bifunctional catalysts due to its thermal stability and the presence of acidic sites on its surface. CuO-In2O3/HNT catalysts demonstrate higher CO2 conversion and DME selectivity compared to non-indium CuO/HNT catalysts. The catalysts were investigated by N2 adsorption, X-ray diffraction, hydrogen-temperature programmed reduction and transition electron microscopy. The acid sites were analyzed by temperature programmed desorption of ammonia. It was shown that CuO/HNT was unstable under reaction conditions in contrast to CuO-In2O3/HNT. The best CuO-In2O3/HNT catalyst provided CO2 conversion of 7.6% with 65% DME selectivity under P = 40 atm, T = 250 °C, gas hour space velocity 12,000 h−1 and H2:CO2 = 3:1. [ABSTRACT FROM AUTHOR]