Controlling metal-support interaction is critical when constructing a highly efficient catalytic system. Herein, different Cu–CeOx interactions are realized by preparing a sequence of CuO/MnCeOx catalysts with varying Mn content. The...

Waste Activated Carbon (WAC), as a typical solid waste, can be utilized by Chemical-Looping Gasification (CLG) technology with an iron-based Oxygen Carrier (OC) to produce valuable synthesis gas. A series of experiments on WAC of the CLG process has been performed in a fixed-bed reactor. The operation parameters and cyclic performance of the iron-based OC have been investigated during CLG reactions. Fresh and cyclic reaction OC samples have been analyzed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). To obtain high-quality syngas with high carbon conversion, the optimal OC/WAC mole ratio, steam flow rate and reaction temperature are 0.1, 0.10 mL/min, and 950 °C, respectively. The iron-based OC exhibits a stable cyclic performance during multiple tests, following the reaction path of Fe2O3 to Fe0.98O in the individual reduction process. Moreover, the iron-based OC is oxidized to almost its initial state after 10 redox tests without obvious sintering and agglomeration phenomena. The WAC of CLG provides a new approach to the comprehensive usage of solid waste, especially with low volatile feedstock.

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The chemical looping oxidative dehydrogenation of propane to propylene (CL-ODHP) replaces molecular oxygen with lattice oxygen (Olatt) in oxygen carriers. This method boosts propylene selectivity by avoiding the deep oxidation of propane. Herein, a series of 10V-XCe/Al oxygen carriers with different Ce contents were prepared to realize different VOx-CeOy interactions. The effect of the Ce content in 10V-XCe/Al oxygen carriers on the CL-ODHP reaction was studied and the optimal Ce content was determined. CeO2 prevents the outward diffusion and evolution of Olatt in VOx carriers to the adsorbed electrophilic oxygen species (Oelec), effectively inhibiting the loss of Olatt, improving the selectivity of propylene, and extending the lifetime and activity of the oxygen carriers. After characterizing and analyzing the oxygen carriers, it was found that 10V-3Ce/Al has the highest specific surface area, highest oxygen capacity, and lowest reducibility. The 10V-3Ce/Al also delivers the highest oxidative dehydrogenation performance. At 550 °C, the average propylene and COx selectivity values of 10V-3Ce/Al were 81.87% and 7.28%, respectively (vs. 62.79% and 25.64% respectively, for 10V/Al). It is demonstrated that 10V-3Ce/Al exhibits good cycle stability with no significant decrease in catalytic performance after 15 cycles. In situ diffuse-reflectance infrared Fourier-transform spectroscopy indicates that CL-ODHP on 10V-3Ce/Al undergoes the Mars-van Krevelen mechanism. The migration and evolution of Olatt in oxygen carriers is controlled by reasonably modifying the metal oxide interactions to improve propylene yield. This work will thus guide the subsequent development of novel and efficient CL-ODHP oxygen carriers.