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

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1434
Author(s):  
Indri Badria Adilina ◽  
Robert Ronal Widjaya ◽  
Luthfiana Nurul Hidayati ◽  
Edi Supriadi ◽  
Muhammad Safaat ◽  
...  

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.

CrystEngComm ◽  
2019 ◽  
Vol 21 (43) ◽  
pp. 6523-6535 ◽  
Author(s):  
Oliver Erhart ◽  
Peter A. Georgiev ◽  
Harald Krautscheid

Structural changes and the unusual H2 adsorption behaviour of a Cu2+-based MOF were studied by X-ray diffraction in combination with DFT modelling and by inelastic neutron scattering.


1962 ◽  
Vol 40 (1) ◽  
pp. 74-90 ◽  
Author(s):  
S. Ganesan ◽  
R. Srinivasan

The reported violation of the Lyddane, Sachs, Teller formula in calcium fluoride has been shown to arise from an error due to the non-application of a symmetry operation in the second neighbor fluorine–fluorine interaction in Cribier's work. By correct deduction of the force constants, the diffuse X-ray scattering measurements are shown to be in accord with the Lyddane, Sachs, Teller formula, but the specific heat calculation on this model is in disagreement with the experimental data.Reflection measurements in the infrared and dispersion of refractive index are shown to be consistent with the principal infrared absorption frequency near 40 μ and not near 51 μ as assumed in the previous model. The calculation of the specific heat using this new infrared frequency agreed with the measurements only at very low and very high temperatures.The two curves are brought into agreement by assuming that the non-Coulomb cross interaction force constant β1 between first neighbor calcium and fluorine decrease with the wave vector. The diffuse X-ray scattering was recalculated on the model, which explained the specific heat data, and was again found to be in agreement with the Lyddane, Sachs, Teller formula. It is suggested that detailed infrared and inelastic neutron scattering studies be made on this crystal.


2006 ◽  
Vol 327 (2-3) ◽  
pp. 311-318 ◽  
Author(s):  
A. Pawlukojć ◽  
W. Sawka-Dobrowolska ◽  
G. Bator ◽  
L. Sobczyk ◽  
E. Grech ◽  
...  

2021 ◽  
Author(s):  
Longfei Lin ◽  
Xue Han ◽  
Buxing Han ◽  
Sihai Yang

This review analyses the reaction mechanisms for the conversion of biomass and derivatives studied by inelastic neutron scattering, synchrotron X-ray diffraction, X-ray absorption spectroscopy, NMR, isotope-labelling and computational techniques.


MRS Bulletin ◽  
2010 ◽  
Vol 35 (11) ◽  
pp. 889-895 ◽  
Author(s):  
R. Caciuffo ◽  
E. C. Buck ◽  
D. L. Clark ◽  
G. van der Laan

Advanced spectroscopic techniques provide new and unique tools for unraveling the nature of the electronic structure of actinide materials. Inelastic neutron scattering experiments, which address temporal aspects of lattice and magnetic fluctuations, probe electromagnetic multipole interactions and the coupling between electronic and vibrational degrees of freedom. Nuclear magnetic resonance clearly demonstrates different magnetic ground states at low temperature. Photoemission spectroscopy provides information on the occupied part of the electronic density of states and has been used to investigate the momentum-resolved electronic structure and the topology of the Fermi surface in a variety of actinide compounds. Furthermore, x-ray absorption and electron energy-loss spectroscopy have been used to probe the relativistic nature, occupation number, and degree of localization of 5f electrons across the actinide series. More recently, element- and edge-specific resonant and non-resonant inelastic x-ray scattering experiments have provided the opportunity of measuring elementary electronic excitations with higher resolution than traditional absorption techniques. Here, we will discuss results from these spectroscopic techniques and what they tell us of the electronic and magnetic properties of selected actinide materials.


Sign in / Sign up

Export Citation Format

Share Document