Pd@PdBOx heterostructure with strong electronic interaction to promote C─H bond activation for glycerol oxidation reaction

Glycerol oxidation reaction (GOR) represents an economical pathway for transforming renewable feedstock to value-added chemicals. However, the inertness of C(sp³)─H bonds of glycerol and intermediates results in the high energy barrier of the dehydrogenation step, relating to poor product selectivity at high glycerol conversion. Here, a carbon nanotube–supported PdBO_x@Pd heterostructure catalyst (PdBO_x@Pd/CNTs) was synthesized in which in situ–exsoluted PdBO_x clusters covalently covered Pd nanoparticles, thus yielding strong electronic interaction between Pd nanoparticles and PdBO_x clusters. The strong electronic interaction in PdBO_x@Pd/CNTs induces the hybridization between Pd(d), B(s, p), and O(s, p) atom orbits, optimizing the adsorption of reactants and intermediates, thus enhancing the activity for the GOR. The density functional theory calculation result reveals that the strong electronic interaction in PdBO_x@Pd/CNTs facilitates the hydrogen transfer in the primary C─H bond of the CH₂OHCHOHCH₂O* intermediate, thus reducing the energy barrier of the rate-determining step and improving glyceric acid selectivity toward the GOR.