Modulation of Brønsted and Lewis Acid Centers for Ni_xCo_3−xO₄ Spinel Catalysts: Towards Efficient Catalytic Conversion of Lignin

Abstract

Rational design and construction of catalysts with regulable activesites for selective cleavage of lignin to produce aromatic monomers remain challenging. Herein, the authors report a new strategy for tuning the active sites of tetrahedral centers (Lewis acid sites) and octahedral centers (Brønsted acid sites) in Ni x Co 3−x O 4 through tailoring the nonstoichiometric ratio of Ni and Co. The ratio of Ni and Co is experimentally optimized for the optimal acidic activity of catalytic cracking of lignin when x = 0.2. The Ni 0.2 Co 2.8 O 4 catalysts achieve an outstanding catalytic conversion (up to 81 wt%) for the lignin cleavage and excellent selective cleavage into aromatic monomers (up to 90.30 wt%), which is mainly attributed to the optimized electron rearrangement, adjustable active sites, and synergistic effect between these two active sites. This work provides a new concept to rationally design solid acid catalysts for the efficient conversion of lignin.

In situconstruction of FeCo alloy nanoparticles embedded in nitrogen-doped bamboo-like carbon nanotubes as a bifunctional electrocatalyst for Zn–air batteries

“…The high-resolution C 1s XPS spectrum can be deconvoluted into four peaks including CC (284.0 eV), C-C (284.8 eV), C-N/C-O (286.0 eV) and O-CO (288.4 eV). 5,19,30 The high-resolution N 1s XPS spectrum (Fig. 3b) can be fitted by four individual peaks located at 398.7, 400.2, 401.3, and 404.1 eV, which are ascribed to pyridinic-N, pyrrolic-N, graphitic-N, and oxidized-N, respectively.…”

“…Moreover, it can provide rich valence state changes, which are significant for the ORR and OER processes. 19,20 However, alloy nanoparticles are still facing the problems of poor stability and serious self-aggregation, especially in harsh electrochemical environments when they are subjected to ORR and OER, resulting in a sharp decline in activity and stability. 15,21 To make highly active and stable catalysts, one promising strategy is to confine the FeCo particles into stable conductive carbon supports.…”

γ‐Valerolactone/H2O‐ Derived Facile Preparation of Lignin‐Based AgNPs to Full Utilization of Lignocellulosic Biomass

“…[1] At present, lignocellulose refining is mainly focused on carbohydrate-derived sugar monomers, [2,3] while most lignin is used as a low-grade fuel. [1,4,5] As a natural aromatic polymer, researchers are dedicated to explore value-added applications of lignin to improve the economy of biorefining process, [1,4] including liquid fuel, [6][7][8] aromatic chemicals, [9,10] functional materials, [11][12][13][14][15] et al. Therein, lignin-based liquid fuel and aromatic chemicals were always transformed by depolymerization.…”

Fully Lignocellulosic Biomass‐Based Double‐Layered Porous Hydrogel for Efficient Solar Steam Generation

“…Lignin, one of the three major components in plant cell walls, is a natural aromatic polymer formed from three phe nylpropane units linked through carbon-oxygen and carboncarbon bonds. [16] Lignin enables strong π-π stacking owing to its rich aromatic ring structures, aliphatic and aromatic hydroxyl groups, and quinone groups, [17] can promote non radiative migration and triggers photothermal conversion. [18] The hydroxyl functional groups of lignin can interact with water molecules through noncovalent interactions to tune the…”