Efficiency of Ni Nanoparticles Supported on Hierarchical Porous Nitrogen-Doped Carbon for Hydrogenolysis of Kraft Lignin in Flow and Batch Systems

Abstract

Ni nanoparticles supported on nitrogen-doped carbon (NDC) prepared via salt-melt synthesis with a hierarchical porosity were successfully applied as the catalyst for the degradation of Kraft lignin. It is shown that Ni-NDC is more efficient when compared to Ni nanoparticles deposited on an N-free carbon support, prepared with similar porosity features (Ni–C) and to Ni nanoparticles deposited on a commercial carbon (Ni-Cref). The efficiency of these materials was compared for reactions performed both in batch and flow reactors, highlighting the effect of the reactor setup on the stability of the recovered catalysts.

Modification of Salt‐Templated Carbon Surface Chemistry for Efficient Oxidation of Glucose with Supported Gold Catalysts

“…The porous carbon supports were prepared by salt‐melt templating followed by carbonisation as described previously . An eutectic salt mixture of KCl and ZnCl 2 (450 mg, 1:2 mass ratio) was mixed in a mortar with glucose (150 g) as the carbon precursor for the synthesis of the nitrogen‐free C Glucose support.…”

“…Owing to the high electric conductivity of such metal‐free catalysts, metal‐free catalysis is particularly important in the field of electrocatalysis . On the other hand, nanocarbon can act as a stabilizing agent or support for catalytically active sites (in most cases metallic or other inorganic nanoparticles) . Nanocarbon materials are attractive catalyst supports because of their high chemical and thermal stability as well as their weak chemical interaction with the metal particles facilitating the formation of active species .…”

“…Before gold deposition, the surface structure of the as‐made C Glucose was modified with a higher density of oxygen‐containing surface groups (C Glucose ‐O) by treatment under air atmosphere, or large parts of the oxygen surface groups were replaced under hydrogen atmosphere at high temperature (C Glucose ‐H). Furthermore, a nitrogen‐doped sample (C Glucosamine ) with similar porosity to that of C Glucose was prepared by using glucosamine instead of glucose as the carbon precursor.…”

Lignin Valorizations with Ni Catalysts for Renewable Chemicals and Fuels Productions

“…The carbon support can also be modified to increase the catalytic activity of hydrogenolysis [98,99]. Doping the carbon support with electron donor atoms such as nitrogen should lead to (1) reduced work function of the support; (2) enhanced partial electron transfer between Ni and the support; (3) increased chemically active sites; (4) increased Ni particle dispersion.…”

“…Doping the carbon support with electron donor atoms such as nitrogen should lead to (1) reduced work function of the support; (2) enhanced partial electron transfer between Ni and the support; (3) increased chemically active sites; (4) increased Ni particle dispersion. Thus, it has been shown that Ni-NDC (nitrogen doped carbon) enhanced the catalytic hydrogenolysis of lignin compared with undoped carbon supports [98]. Using NiMgAl layered double hydroxides and lignosulfonate to prepare the Ni metal catalyst supported on MgAl modified carbon support, the 3d electron distribution of surface layer Ni can be altered to promote highly selective C-O bond cleavage [99], while the Ni/C catalysts only showed high conversion but lower monomer selectivity and the mixed oxide Ni/MgAlO showed little or no activity.…”