Production of Aryl Oxygen-Containing Compounds by the Pyrolysis of Bagasse Alkali Lignin Catalyzed by LaM_0.2Fe_0.8O₃ (M = Fe, Cu, Al, Ti)

Abstract

A series of LaM0.2Fe0.8O3 (M = Fe, Cu, Al, Ti) samples synthesized by the sol–gel method were used to catalyze the pyrolysis of bagasse alkali lignin (BAL) to produce aryl oxygen-containing compounds. The effects of doping metal ions in the B-site of LaFeO3 were investigated by X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller, and X-ray photoelectron spectrometer. Furthermore, the catalytic pyrolysis performances of the perovskites were evaluated by thermogravimetric analysis and the fixed-bed microreactor, and the gaseous and liquid pyrolysis products were analyzed by GC and gas chromatography/mass spectrometry (GC/MS), respectively. The results indicated that the perovskites have a cubic crystal phase, porous structure, and large specific surface area. After doping Cu, Al, and Ti ions in the B-site of perovskites, the grain sizes were refined, the performance of catalyzing BAL pyrolysis was improved, and the yields of liquid pyrolysis products increased by 24.1–39.1%. The selectivities of CO2 and CO in gaseous products decreased by 5.8–16.3 and 26.0–34.8%, respectively, which resulted from the inhibition of decarboxylation and decarbonylation. The total selectivities of target products, i.e., aryl oxygen-containing compounds (including phenolics, guaiacols, syringols, and phenylates) obtained from BAL pyrolysis catalyzed using perovskites were all greater than 74 wt %, which was higher than that obtained from the pyrolysis of pure BAL (62 wt %) in the absence of catalyst. After 5 cycles of redox reaction, the perovskite still showed a well-maintained structural and catalytic stability.

Green and Efficient Al-Doped LaFexAl1–xO3 Perovskite Oxide for Enhanced Phosphate Adsorption with Creation of Oxygen Vacancies

“…The lattice spacing of 0.272–0.274 nm (Figure f) for LFO material corresponds to the crystal planes of LaFeO 3 (110) (PDF no. 97-002-9234) . The different lattice spacings of 0.284, 0.335, and 0.452 nm were interconnected in LFAO-3 (Figure g), which indicated that Al doping caused lattice distortion …”

“…The generation of the concomitant peak splitting and the change in electron binding energy reflect the ability of the O 2p electron to afford La, i.e., they reflect the covalent nature of La–O. With the increasing Al-doped content, the electron binding energy of La 3d tends to increase (0.3–0.8 eV), which indicates that when the covalent nature of La–O decreases, lattice oxygen may participate in phosphate adsorption. , With increasing Al-doped content, the electron binding energies of Al 2p (Figure c) and Fe 2p (Figure d) tend to increase and decrease, respectively; Al doping may cause a change in the Fe valence state . The XPS spectra of the Fe 2p region can be fitted into peaks at ∼708.7–710.5 and 723–724 eV belonging to Fe 2+ and at 710.5–712.6 and 724.8–725.9 eV belonging to Fe 3+ (Figure d). ,, After doping with Al, the ratio of Fe 2+ /Fe 3+ tends to increase, indicating that additional Fe 3+ is converted to Fe 2+ (Table S2), which may generate oxygen vacancies and adsorb oxygen on the surface because of charge compensation.…”

“…221) and were in agreement with the PDF card (no. 97-002-9234), 40 indicating that the phase structure of LFO was kept after Al doping (Figure 1a,b). The XRD peaks including (110) of LaFe 1−x Al x O 3 were found to shift toward a higher angle as the Al concentration increased, indicating the preferred orientation of the crystal plane distortion.…”

“…97-002-9234). 40 The different lattice spacings of 0.284, 0.335, and 0.452 nm were interconnected in LFAO-3 (Figure 2g), which indicated that Al doping caused lattice distortion. 46 The profile of perovskite LFO seems to follow a type-II curve, whereas the Al-doped LaFe 1−x Al x O 3 perovskite follows a type-IV curve and a typical H4 hysteresis loop.…”

ReaxFF Study on the Effect of CaO on Cellulose Pyrolysis

“…Rapid pyrolysis of biomass is one of the most promising methods to convert abundant biomass into bio-oil. − Bio-oil has a high oxygen content, low calorific value, poor stability, and high corrosiveness, which means that it cannot directly replace petroleum products. − Therefore, various catalysts and additives have been tested during biomass pyrolysis, in order to improve the quality of the bio-oil products through a series of deoxygenation reactions. , …”