Graphitic Carbon Nitride Supported Ultrafine Pd and Pd–Cu Catalysts: Enhanced Reactivity, Selectivity, and Longevity for Nitrite and Nitrate Hydrogenation

Novel Pd-based catalysts (i.e., Pd and Pd–Cu) supported on graphitic carbon nitride (g-C3N4) were prepared for nitrite and nitrate hydrogenation. The catalysts prepared by ethylene glycol reduction exhibited ultrafine Pd and Pd–Cu nanoparticles (∼2 nm), and they showed high reactivity, high selectivity toward nitrogen gas over byproduct ammonium, and excellent stability over multiple reaction cycles. The unique nitrogen-abundant surface, porous structure, and hydrophilic nature of g-C3N4 facilitates metal nanoparticle dispersion, mass transfer of reactants, and nitrogen coupling for nitrogen gas production to improve catalytic performance.