Catalytic Cleavage of the C–O Bond in Lignin and Lignin-Derived Aryl Ethers over Ni/AlP_yO_x Catalysts

Abstract

The conversion of lignin into value-added chemicals is one of the important ways for sustainable development. Herein, phytic acid, a biomass-derived chemical, was used as the phosphorus source and pore former to synthesize the AlP y O x support. After loading Ni, the Ni/AlP y O x catalysts were found to be highly active in the catalytic conversion of lignin model compounds to high-value-added chemicals under mild conditions. The benzyl phenyl ether (α-O-4 lignin model compound) could be completely converted into toluene and phenol with near-equivalent selectivity at 30 °C and 3 MPa H2. Diphenyl ether and 2-phenoxy-1-phenylethanol were also used as 4-O-5 and β-O-4 model compounds of lignin, respectively. The unique activity of Ni/AlP0.5O x could be attributed to metallic Ni that interacts with AlP0.5O x and the unique adsorption of substrates on the carrier. Lignin can also be degraded over Ni/AlP0.5O x via selective cleavage of the C–O bond, and 26.60 wt % yield of identified monomers was obtained.

Al-Doped Core–Shell-Structured Ni@Mesoporous Silica for Highly Selective Hydrodeoxygenation of Lignin-Derived Aldehydes

“…Compared to Ni@ mSiO 2 , all of the binding energy shifted to higher binding energy (+0.1 eV) in Ni@Al 3 -mSiO 2 , demonstrating the effect of Al doping on the electronic structure of Ni. Notably, the result was inconsistent with the XRD results (no signal was detected associated with nickel oxide species), which might be attributed to the exposure of catalysts to air during the measurement and the presence of a low percentage of nickel oxide species on the catalyst surface …”

“…Notably, the result was inconsistent with the XRD results (no signal was detected associated with nickel oxide species), which might be attributed to the exposure of catalysts to air during the measurement and the presence of a low percentage of nickel oxide species on the catalyst surface. 30 The Ni nanoparticles size (d Ni( 111) ) was determined using the Scherrer equation (eq 1, Supporting Information), and the values are shown in Table 1. The sizes of the Ni nanoparticles for Ni@Al x -mSiO 2 (8.1 nm Ni@Al 1 -mSiO 2 , 8.4 nm for Ni@ Al 3 -mSiO 2 , 7.8 nm for Ni@Al 5 -mSiO 2 ) were larger than that of Ni@mSiO 2 (5.0 nm), indicating that the incorporation of Al increased the size of Ni nanoparticles.…”

Removal of Cr(III) Ions from Water Using Magnetically Separable Graphene-Oxide-Decorated Nickel Ferrite Nanoparticles

“…The presence of ether functional group in the reduced GO makes sense, as it is well-known that this group is very difficult to be reduced at low temperatures and atmospheric pressures in the absence of a proper catalyst. 61 Finally, a comparison of the O 1s peaks revealed for the NiFe 2 O 4 and NiFe 2 O 4 /GO samples clearly evidence the presence of OH groups at the surface of NiFe 2 O 4 NPs (Figure 5g). It should be mentioned that the O 1s emission from OH groups present in GO of the nanocomposite also appears around 530.6 eV.…”

Photocatalytic transfer hydrogenolysis of aryl ethers

“…The 4-O-5 linkage is one of the basic and most inert linkages in lignin, and its cleavage has drawn considerable attention. [6][7][8][9][10][11] Well-designed molecular catalysts and heterogeneous catalysts have been developed to break the 4-O-5 linkage via hydrogenolysis under a H 2 atmosphere, [12][13][14][15][16][17][18][19] and in particular, much effort has been devoted to realizing this transformation under mild conditions, such as additivefree, low-pressure H 2 , and low-temperature conditions. [20][21][22][23][24][25][26][27][28] The transfer hydrogenation strategy utilizes biomass-derived alcohols, carboxylic acids, and even water as hydrogen donors, avoiding the use of hydrogen gas.…”