Understanding the Surface Characteristics of Biochar and Its Catalytic Activity for the Hydrodeoxygenation of Guaiacol

Abstract

Biochar (BCR) was obtained from the pyrolysis of a palm-oil-empty fruit bunch at 773 K for 2 h and used as a catalyst for the hydrodeoxygenation (HDO) of guaiacol (GUA) as a bio-oil model compound. Brunauer–Emmet–Teller surface area analysis, NH3 and CO2-temperature-programmed desorption, scanning electron microscope–dispersive X-ray spectroscopy, CHN analysis and X-ray fluorescence spectroscopy suggested that macroporous and mesoporous structures were formed in BCR with a co-presence of hydrophilic and hydrophobic sites and acid–base behavior. A combination of infrared, Raman and inelastic neutron scattering (INS) was carried out to achieve a complete vibrational assignment of BCR. The CH–OH ratio in BCR is ~5, showing that the hydroxyl functional groups are a minority species. There was no evidence for any aromatic C–H stretch modes in the infrared, but they are clearly seen in the INS and are the majority species, with a ratio of sp3–CH:sp2–CH of 1:1.3. The hydrogen bound to sp2–C is largely present as isolated C–H bonds, rather than adjacent C–H bonds. The Raman spectrum shows the characteristic G band (ideal graphitic lattice) and three D bands (disordered graphitic lattice, amorphous carbon, and defective graphitic lattice) of sp2 carbons. Adsorbed water in BCR is present as disordered layers on the surface rather than trapped in voids in the material and could be removed easily by drying prior to catalysis. Catalytic testing demonstrated that BCR was able to catalyze the HDO of GUA, yielding phenol and cresols as the major products. Phenol was produced both from the direct demethoxylation of GUA, as well as through the demethylation pathway via the formation of catechol as the intermediate followed by deoxygenation.

Effect of natural aging on biochar physicochemical property and mobility of Cd (II)

“…In AB, the vibration absorption peak of Si-O-Si near 466 cm -1 was significantly enhanced, indicating more pronounced stretching vibration after adsorption of Cd 2+ . The -OH vibration band could be attributed to the hydroxyl groups formed upon water adsorption on biochar (Adilina et al, 2021). The intensity of the -OH vibration band increased after adsorption of Cd 2+ .…”

Activation of Nitrogen-Doped Carbon Materials on the C–N Bond and C–O Bond: Modeling Study Toward Enhanced Pyrolysis Products

“…Nitrogen-doped carbon materials have been shown to catalyze bond breaking and hydrogen activation of aryl ethers and NCCs. , In addition, the carbon catalyst will not perform excessive hydrogenation on aromatic groups due to its moderate reactivity, thereby improving the efficiency of hydrogenation. , Chen et al using bamboo to obtain N-doped carbon material of which catalytic deoxygenation for phenol production was confirmed . Adilina et al also tested the HDO performance of biochar on guaiacol by experimental methods . Thus, the carbon catalyst is a low-cost, acid- and alkali-resistant, and environmentally friendly catalyst material.…”

“…48 Adilina et al also tested the HDO performance of biochar on guaiacol by experimental methods. 50 Thus, the carbon catalyst is a low-cost, acid-and alkali-resistant, and environmentally friendly catalyst material. However, the existing literature rarely discusses the hydrogenation activity of carbon materials and the microscopic mechanisms of C−O bond and C−N activation.…”