Enhanced catalytic hydrogenation of aqueous bromate over Pd/mesoporous carbon nitride

• Pd/mesoporous carbon nitride (Pd/MCN) was synthesized for bromate reduction.
• Pd/MCN exhibited high catalytic activity toward bromate hydrogenation.
• Bromate adsorption and Pd size had a major impact on catalytic reduction.
• Solution pH and coexisting anions influenced bromate reduction on Pd/MCN.

Pd catalysts supported on mesoporous carbon nitride (MCN) were synthesized and the liquid phase catalytic hydrogenation of bromate was investigated. Characterization results showed that the Pd/MCN catalysts had large BET surface area, high isoelectric point (IEP), ordered mesoporous structure and well dispersed Pd particles in the pores of MCN. Compared with Pd/active carbon (Pd/AC) and Pd/ordered mesoporous carbon (Pd/CMK-3), Pd/MCN displayed higher catalytic activity for bromate reduction, due to its mesoporous structure and high IEP. The bromate hydrogenation process over Pd/MCN followed the Langmuir–Hinshelwood model, reflecting an adsorption controlling reaction mechanism. The pH-catalytic activity linked relationship was related to the adsorption ability of catalysts. Turn over frequencies (TOFs) of the surface Pd sites were found to be dependent on Pd particle size. The coexisting anions suppressed the reduction of bromate. The present results demonstrated that Pd/MCN could be a promising catalyst for the application on bromate hydrogenation.