Pd Nanoparticles Loaded on CoAlCe Layered Double Oxide Nanosheets for Phenol Hydrogenation

Abstract

The catalytic upgrading of phenolic derivatives is vital for the efficient utilization of biomass resources. Herein, we construct a reductive layered double oxide material (CoAlCe-LDO) with the Ce−Co interface and abundant oxygen vacancy (V O ) via heat-treating layered double hydroxide (LDH) precursors. The support spontaneous in situ redox method is employed to prepare the supported catalyst using CoAlCe-LDO as a support and reductant. Interestingly, highly dispersed Pd nanoparticles prefer to distribute at the contact edge of the Ce− Co interface. Pd 2+ is successfully reduced to Pd 0 by the reductive Co/Ce sites. Due to the redox reaction between the support and Pd species, a strong metal−support interaction is introduced. The Pd/CoAlCe-LDO catalyst shows high activity for phenol hydrogenation under mild conditions and a low molar ratio of Pd to phenol. The kinetic study suggests that the highly dispersed Pd sites could preferably activate H 2 molecules, thereby boosting the rapid phenol hydrogenation.

Liquid-Phase Hydrogenation of Phenol in an Advanced Gas–Liquid Concurrent Upflow Fixed-Bed Reactor with Membrane Dispersion

“…Table lists the experimental results of this work and literature under their respective optimal operation conditions. ,,− Compared with the results reported in the literature, the phenol conversion and cyclohexanone selectivity of the advanced fixed-bed reactor in this work are both at a higher level. Although the improved reactor is lower than some experimental results in the autoclave, , it avoids the problem of separation between the ultrafine catalysts and liquid products and can realize long-term continuous operation, which is conducive to the large-scale amplification of liquid-phase phenol hydrogenation.…”

Hydrogenolysis of furfuryl alcohol over CuCeMgAl mixed metal oxide catalysts derived from layered double hydroxides

“…When Ce loading reached 0.2 wt%, the diffraction peak for fluorite CeO 2 at 28.4° was observed, demonstrating the formation of CeO 2 phases. 23…”

“…When Ce loading reached 0.2 wt%, the diffraction peak for fluorite CeO 2 at 28.4°was observed, demonstrating the formation of CeO 2 phases. 23 Elemental analysis of calcined and reduced MMO catalysts was performed using ICP-OES, and results are shown in Table 1. The actual loadings and metal molar ratios of the samples were a bit different from the designed values.…”

Increased Hydrogenation Rates in Pd/La-Al2O3 Catalysts by Hydrogen Transfer O(-La) Sites Adjacent to Pd Nanoparticles

“…However, because of the high chemisorption energies, competitive adsorption of reactants and hydrogen occurs on the Pd surface . To promote the efficient conversion of the reactant, the partial pressure of hydrogen is often much higher than the stoichiometric ratio and sometimes is extremely high, , causing excess hydrogen surface coverage, which inhibits the adsorption of the reactant . Spillover, which is more likely to occur on reducible supports, − is one way to solve this problem.…”

“…The phenol hydrogenation was carried out at 90 °C with 25 mg of catalyst, and the other processes were the same as those in the literature. 16 For this, 15 mL of cyclohexane (solvent), 0.04 g of phenol (substrate), and 300 μL of n-dodecane (internal standard) were reacted in 0.4 MPa hydrogen. The nitrobenzene hydrogenation is similar to that of phenol.…”