Construction of High-Density Fe Clusters Embedded in a Porous Carbon Nitride Catalyst with Effectively Selective Transformation of Benzene

Abstract

An Fe-based heterogeneous catalyst is an attractive Fenton-like catalyst for phenol synthesis due to many advantages. Nevertheless, it is challenging to control the particle size in various high-loading Fe-based materials, which limits its activity and selectivity. In this work, ultra-small Fe clusters embedded in a 3D porous interconnected open-framework g-C3N4 (denoted FeN x /CCN) were successfully fabricated by the combination of a mechanochemical reaction with one-step pyrolysis. Various characterization results showed that ultra-small Fe clusters with a high loading of 32% were uniformly distributed in the hierarchical porous carbon nitride, which offered an access for faster transportation of charge carriers. Fe sites were probably coordinated with carbon nitride by Fe2+–C N–Fe3+ and Fe–N x bonding. High-density Fe clusters could provide abundant active sites and improve the light absorption and the activating ability of H2O2. By taking advantage of semiconductor functions in combination with a rich porous structure and high-density active sites, the novel Fe cluster catalyst exhibited high activity and stability in phenol synthesis, with a maximum phenol yield of 28.1% in visible light. Combining the experimental results with Fenton chemistry, we proposed a possible photocatalytic reaction mechanism. Our work will give valuable information on the development of active metal cluster nanocatalysts for organic synthesis.

Boosting Solvent-Free Aerobic Oxidation of Benzylic Compounds into Ketones over Au-Pd Nanoparticles Supported by Porous Carbon

“…Typical type-IV isotherms were observed in both MC and Au-Pd/MC [41]. The presence of hysteresis loops at a relative pressure of 0.2-0.8 implied a mesoporous character in both samples [34]. Both Au-Pd/MC and MC displayed considerable N2 adsorption at a low pressure lower than 0.1, indicating rich microporosity.…”

“…Then, the obtained hydrochars were further pyrolyzed at 550 • C under an N 2 atmosphere to improve the graphitization degree and retain plentiful oxygen-containing functional groups [32,33]. Moreover, a large number of small molecular gases (e.g., CO, CO 2 , and H 2 O) were released to generate many pores during this carbonization process [34]. Therefore, spherical carbon with a porous structure and rich porosity was obtained.…”

Copper-containing POM-based hybrid P2Mo22V4Cu4 nanocluster as heterogeneous catalyst for the light-driven hydroxylation of benzene to phenol

“…Among them, the homogeneous catalyst will be dissolved in the reaction solution and cannot be easily recycled, while the active components of the supported catalysts will inevitably be lost in the reaction. 2,10,[21][22][23][24][25][26] Consequently, the preparation of a favorable and stable photocatalyst for one-step oxidation of benzene to phenol is still a challenging direction. 27 Heteropolyacids are oxygen-containing polyacids whose structure consists of a small number of heteroatoms and polyatoms forming polyhedra {MO X } with oxygen atoms, which are later assembled by co-edge and co-angle forms.…”

Counter-current chromatography for lignin monomer–monomer and monomer–oligomer separations from reductive catalytic fractionation oil

“…1. We first measured the partition coefficients of common aromatic monomers in lignin oils from hardwood, softwood, and herbaceous feedstocks 27,28 using the HEMWat (hexane, ethyl acetate, methanol, and water) solvent system (Table S1 †). 24 Based on the measured partition coefficients, we used the selected solvent system for CCC to separate lignin oils from poplar, pine, and corn stover, demonstrating in all cases both monomer-monomer and monomer-oligomer separations.…”