Ru Promoted MgO and Al-Modified MgO for Ethanol Upgrading

Ni-Based Hydrotalcite (HT)-Derived Cu Catalysts for Catalytic Conversion of Bioethanol to Butanol

Catalytic conversion of biomass-derived ethanol into n-butanol through Guerbet coupling reaction has become one of the key reactions in biomass valorization, thus attracting significant attention recently. Herein, a series of supported Cu catalysts derived from Ni-based hydrotalcite (HT) were prepared and performed in the continuous catalytic conversion of ethanol into butanol. Among the prepared catalysts, Cu/NiAlOx shows the best performance in terms of butanol selectivity and catalyst stability, with a sustained ethanol conversion of ~35% and butanol selectivity of 25% in a time-on-stream (TOS) of 110 h at 280 °C. While for the Cu/NiFeOx and Cu/NiCoOx, obvious catalyst deactivation and/or low butanol selectivity were obtained. Extensive characterization studies of the fresh and spent catalysts, i.e., X-ray diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Hydrogen temperature-programmed reduction (H2-TPR), reveal that the catalysts' deactivation is mainly caused by the support deconstruction during catalysis, which is highly dependent on the reducibility. Additionally, an appropriate acid-base property is pivotal for enhancing the product selectivity, which is beneficial for the key process of aldol-condensation to produce butanol.

A highly stable and sensitive ethanol sensor based on Ru-decorated 1D WO3 nanowires

Decorating materials with noble metal catalysts is an effective method for optimizing the sensing performance of sensors based on tungsten trioxide (WO₃) nanowires. Ruthenium (Ru) exhibits excellent catalytic activity for oxygen adsorption/desorption and chemical reactions between gases and adsorbed oxygen. Herein, small Ru nanoparticles were uniformly distributed on the surface of one-dimensional WO₃ nanowires. The nanowires were prepared by the electrospinning method through an ultraviolet (UV) irradiation process, and decoration with Ru did not change their morphology. A sensor based on 4% Ru nanowires (NWs) shows the highest response (∼120) to 100 ppm ethanol, which was increased around 47 times, and the lowest ethanol detection limit (221 ppb) at a lower temperature (200 °C) displays outstanding repeatability and stability even after 45 days or in higher-humidity conditions. Moreover, it also has faster response–recovery features. The improvement in the sensing performance was attributed to the stable morphology of the nanowires, the sensitization effect of Ru, the catalytic effect of RuO₂ and the optimal atomic utilization efficiency. This work offers an effective and promising strategy for promoting the ethanol sensing performance of WO₃.

Decorating Ru does not effect the morphology of NWs, increased the oxygen vacancies, adsorbed oxygen. This strategy results in a better sensing performance (∼120 to 100 ppm ethanol was increased around 47 times at 200 °C) and humidity resistance.

The catalytic dehydrogenation of ethanol by heterogeneous catalysts

In this review, recent advances in the catalytic dehydrogenation of ethanol to acetaldehytde with the release of hydrogen catalyzed by a heterogeneous catalyst aresummerized and discussed.