Comparison of Combustion and Pyrolysis Behavior of the Peanut Shells in Air and N2: Kinetics, Thermodynamics and Gas Emissions

The influences of four heating rates on the combustion and pyrolysis behavior in the N2 and air atmosphere were investigated by the Fourier transform infrared spectrometry (FTIR) and thermogravimetric (TG) analysis. the distributed activation energy model (DEAM) and Flynn-Wall-Ozawa (FWO) were used to estimate Ea and A, ΔH, ΔG and ΔS. Experimental results showed that the similar thermal behavior emerged, but the temperatures in the air and N2 atmospheres representing the end of the reaction were about 500 °C and 550 °C, respectively. The results of FTIR showed the peak positions were basically the same, but the concentrations of aromatics, aldehydes and ketones produced by pyrolysis in the N2 atmosphere were higher. When the heating rate was 20 K/min, the comprehensive combustion parameters were 56.442 and 6.871 × 10−7%2/(min2• K3) in the air and N2 atmospheres, respectively, indicating that the peanut shells had great potential to become bioenergy

Diving into the interface-mediated Mars-van Krevelen (M−vK) characteristic of CuOx-supported CeO2 catalysts

The unique interface synergistic catalytic properties for metal oxide-supported catalysts have long been explored in several critical heterogeneous catalytic processes (e.g., CO oxidation reactions). However, interfacial synergistic catalysis is still a hitherto undescribed mechanism due to the lack of direct evidence at the atomic level. Thereinto, the CuOx-supported CeO2 (CuOx/CeO2) catalyst is a typical case. Herein, a combination study including representative theoretical calculations, in situ DRIFTS spectra and tailored molecular probe experiments supports a new carbonate-interface mediated Mars-van Krevelen (M−vK) mechanism for CO oxidation, i.e., CO molecules form carbonate intermediate species directly between spatial proximity (2.99 Å) double lattice oxygen sites with low oxygen vacancies formation energy (EformOv = 0.82 eV/0.83 eV) at the copper−ceria interface. The reaction energy barrier of this process is 0.32 eV, much lower than the 1.23 eV of the conventional M−vK mechanism. Besides, the spatial effect of double oxygen vacancies (Ov) generated by the depletion of intermediate carbonate species promotes the sustained and dynamic activation of O2, hence facilitating the efficient operation of the M−vK mechanism at low temperatures