Acid-Modified Natural Bauxite Mineral as a Cost-Effective and High-Efficient Catalyst Support for Slurry-Phase Hydrocracking of High-Temperature Coal Tar

In this paper, we present a novel kind of supported Mo catalyst for hydrocracking high-temperature coal tar (HTCT), a byproduct of coal carbonization/gasification that has an abundant supply and is considered as a potential feedstock to refineries in the future. The catalysts are featured by their supports derived from a natural bauxite that has a low price and abundant reserves in the earth. The natural bauxite was modified via acid treatments with different acids (i.e., HCl, H₂C₂O₄, H₃PO₄, HNO₃, and H₃BO₃), and different supports were obtained. The physicochemical properties of the supports were systematically characterized, and the slurry-phase hydrocracking performance of the corresponding catalysts was assessed in a batch autoclave reactor. The results show that the modifications of the calcined natural bauxite with both HCl and H₂C₂O₄ yield two supports with an enlarged specific surface area and pore volume and enhanced acidity as a result of the leaching of Fe₂O₃ and the enrichment of Al₂O₃. Such characteristics are responsible for the outstanding catalytic performance of the derived catalysts. Moreover, the bauxite-derived support can reduce the total catalyst cost by 50–60% compared to a conventional γ-Al₂O₃ support. Our success provides an economic and effective catalyst for refiners to convert unconventional heavy feedstocks to value-added products

Sacrificial Adsorbate Strategy Achieved Strong Metal–Support Interaction of Stable Cu Nanocatalysts

A new adsorbate-mediated strategy was developed to enhance the metal–support interaction of Cu/CeO₂, aiming to improve its catalytic activity and sintering resistance in the water–gas shift (WGS) reaction. By treating Cu/CeO₂ in a 20CO₂/2H₂ gas mixture for the formation of surface HCO_<i>n</i> (<i>n</i> = 2, 3), there was significant enhancement of the interaction between CeO₂ and Cu. The HCO<i>_n</i> adsorbate was removed through calcination in an O₂/Ar atmosphere at 400 °C for 6 h. The as-obtained Cu/CeO₂ catalyst was compared with the untreated counterpart in the WGS reaction. It was observed that CO conversion at 350 °C was 86% and 47%, respectively, over the two catalysts. The superiority of the former is attributed to the enhanced interaction between Cu and CeO₂. In a run of 15 h at 400 °C, the treated catalyst showed no obvious sign of deactivation

Effects of Doping Rare Earth Elements (Y, La, and Ce) on Catalytic Performances of CoMo/MgAlM for Water Gas Shift Reaction

Rare earth element (La, Y, and Ce) modified MgAl-hydrotalcites of MgAlM were synthesized from coprecipitation and calcination, and further loaded with CoMo active species to give CoMo/MgAlM catalysts. X-ray powder diffraction, inductively coupled plasma, and N₂ adsorption isotherms indicate that MgAlM possess large BET surface areas (58–91 m²/g), and rare earth elements were successfully introduced into samples. CO₂-TPD (temperature-programmed desorption), NH₃-TPD, H₂-TPR (temperature-programmed reduction), H₂S-TPS (temperature-programmed sulfidation), and Raman spectra indicate the presence of unique interactions between rare earth elements and Mo active species, which strongly affect the reduction and sulfidation behaviors of these catalysts. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis suggest that the addition of rare earth elements decreases the slab length and stacking numbers of MoS₂ and promotes the sulfidation degree of Mo oxides. The above characteristics make CoMo/MgAlM act as highly active catalysts for the water gas shift reaction (WGSR). This work develops a facile and cost-effective method for rational design of efficient catalysts for WGSR in industrial processes