Pyridinic nitrogen dominated doping on Pd/carbon catalysts for enhanced hydrogenation performance

Limin He; Yangdong Wang; Can Wang; Zhicheng Liu; Zaiku Xie

doi:10.3389/fchem.2022.1046058

Pyridinic nitrogen dominated doping on Pd/carbon catalysts for enhanced hydrogenation performance

Front Chem. 2022 Nov 2:10:1046058. doi: 10.3389/fchem.2022.1046058. eCollection 2022.

Authors

Limin He¹, Yangdong Wang¹, Can Wang¹, Zhicheng Liu¹, Zaiku Xie²

Affiliations

¹ State Key Laboratory of Green Chemical Engineering and Industrial Catalysis, Shanghai Research Institute of Petrochemical Technology, SINOPEC Corp, Shanghai, China.
² China Petrochemical Corporation (SINOPEC Group), Beijing, China.

Abstract

The hydrogenation of 4-carboxylbenzaldehyde over Pd catalysts is a crucial process during the production of pure terephthalic acid. Herein, ZIF-8 derived carbon materials (NC) with adjustable N types were synthesized and used as the supports of Pd catalysts. Pd supported on NC with 50.5% of pyridinic N exhibited best hydrogenation activity with a TOF value of 4.1 min^-1. The microstructures of NC support and electronic structures of Pd in Pd/NC were investigated by techniques such as XRD, N₂ physisorption, XPS, H₂-O₂ titration and TEM. The nitrogen species in CN surface not only can adjust chemical state and dispersion of Pd nanoparticles (NPs), but also promote the adsorption and activation capability of H₂ molecular. Besides, the ratio of Pd⁰/Pd²⁺ and Pd dispersion were closely correlated with pyridinic nitrogen content. The improvement in hydrogenation activity and stability of Pd/CN catalyst in relative to Pd/C were ascribed to the synergistic effect of pyridinic nitrogen and active site Pd⁰.

Keywords: carbon materials; hydrogenation; pallidium; pyridinic nitrogen; synergistic effect.