Boron-Doped PdNanoparticles with a Regulated <i>d</i>‑BandCenter for Hydrogenation of Benzoic Acid

Selective hydrogenation of benzoic acid (BA) is regarded as a sustainable and environmentally friendly strategy to produce highly valued cyclohexanecarboxylic acid (CCA). However, the activation of the benzene ring with a conjugated structure in BA molecules requires high resonance energy, making effective hydrogenation challengeable. Herein, the boron-doped Pd nanoparticles supported on Al₂O₃ (B_<i>x</i>Pd/Al₂O₃) were synthesized using NaBH₄ as both a reducing agent and boron source, enabling efficient hydrogenation of BA to CCA under mild reaction conditions. By adjusting the initial amount of NaBH₄, the B-doped Pd nanoparticles with an optimized B content of 1.3 <i>wt</i>.% exhibited a pronounced reduced electronic density, resulting in an upshift of the <i>d</i>-band center and enhanced reactant adsorption while maintaining unaffected product adsorption. Consequently, both the activity and stability of the B_1.3Pd/Al₂O₃ catalysts for BA hydrogenation were significantly improved compared to that of the Pd/Al₂O₃ catalysts. These findings present a valuable strategy for regulating the <i>d</i>-band center of metal nanoparticles through B element doping, offering significant implications in terms of academic and practical applications.