Solvent‐Free Selective Oxidation of Benzyl Alcohol at Atmospheric Pressure Catalyzed by Pd Nanoparticles Supported on g‐C₃N₄ Materials with Tunable Nitrogen Distributions

Abstract

Solvent‐free atmospheric selective oxidation of benzyl alcohol (BZA) by molecular oxygen is a promising and green process for the synthesis of benzaldehyde (BZL). Supported Pd nanoparticles have been widely reported in the catalytic selective oxidation of BZA. Wherein, the activity depends on the chemical valence and dispersion of the Pd nanoparticles. Herein, a series of thermally exfoliated g‐C3N4 (eg‐C3N4) have been synthesized under various gas conditions (air/N2) and then applied as catalyst supports to load Pd nanoparticles. The physicochemical properties of the prepared Pd/eg‐C3N4 materials have been characterized by N2 adsorption–desorption, XRD, FT‐IR, UV–vis, XPS, and TEM. Pd nanoparticles dispersed well on the supports, and the distributions of Pd and nitrogen species of the catalysts were related to the gas conditions of the supports. In the selective oxidation of BZA, 2.5Pd/eg‐C3N4‐AN catalyst afforded conversion of BZA and the selectivity to BZL of 88% and 92%, respectively. The metallic Pd0 species are considered the catalytic sites of Pd/eg‐C3N4 in the catalytic reaction and meanwhile, the basic Nb species of eg‐C3N4 were beneficial to the overall activity of the catalyst.

Ultrathin Sulfur‐Doped g‐C3N4 Nanosheets Controlled by Steam Activation for Enhanced Visible‐Light Photocatalytic Performance

“…Diffractograms determined via XRD are shown in Figure 3b, all the g‐C 3 N 4 samples exhibit two characteristic diffraction peaks at 14° and 27°. The characteristic diffraction peak at 14° corresponds to the (100) plane of g‐C 3 N 4 belonging to the in‐plane repeating unit of g‐C 3 N 4 [31] . The intense diffraction peak at 27° corresponds to the (002) plane of g‐C 3 N 4 , which is the repeating unit of the aromatic layered structure [32] .…”

“…The characteristic diffraction peak at 14°c orresponds to the (100) plane of g-C 3 N 4 belonging to the inplane repeating unit of g-C 3 N 4 . [31] The intense diffraction peak at 27°corresponds to the (002) plane of g-C 3 N 4 , which is the repeating unit of the aromatic layered structure. [32] The intensity of the (100) plane peak of CNÀ S-X decreases compared to that of CN and CNÀ S, indicating the presence of numerous structural defects in CNÀ S-X after steam activation treatment.…”