Liquid‐phase and Solvent‐free Selective Oxidation of Benzyl Alcohol With Atmospheric O 2 Efficiently Catalyzed by Bimetallic Pd‒Au Nanoparticles Supported on Carbon Nitride

ABSTRACT The liquid‐phase selective oxidation of benzyl alcohol (BZA), particularly conducted under solvent‐free conditions using atmospheric O 2 as the oxidant, represents a sustainable approach for benzaldehyde (BZL) synthesis. Among numerous heterogenous catalysts developed, supported Pd nanoparticles have showed high activity and selectivity for this process. Herein, to further upgrade the activity of the Pd‐based catalysts, graphitic carbon nitride (g‐C 3 N 4 ) was employed as a support for Pd–Au bimetallic nanocatalysts (Pd x Au y /g‐C 3 N 4 ‐ T ). The supported Pd and Au formed alloy nanoparticles, with the introduction of Au reducing the particle size of the supported metals. Moreover, strong interaction between the nitrogen atoms in the g‐C 3 N 4 support and the supported metals was evidenced. In the liquid‐phase and solvent‐free selective oxidation of BZA with O 2 , the bimetallic catalysts exhibited higher catalytic activity than their monometallic counterparts. Under mild reaction conditions (90°C and 6 h), merely 20 mg of 1Pd 3 Au 1 /g‐C 3 N 4 ‐350 catalyst achieved a high BZL yield of 62.7%. Furthermore, the catalyst can be reused at least six times without any loss of activity and meanwhile exhibited activity toward other aromatic alcohols.