Tuning electronic structure of palladium from wheat flour-derived N-doped mesoporous carbon for efficient selective hydrogenation of acetylene

Designing efficient and sustainable catalysts for semi-hydrogenation of acetylene is of critical importance, but challenging. A novel and easily scaled-up strategy is described in this work for a well-performing Pd-based catalyst (Pd@NMC) fabrication by using a cheap and widely available biomass, wheat flour, as support precursor. The optimized catalyst exhibits superior performance for purification of crude ethylene stream compared with the commercial counterparts, providing an outstanding selectivity of exceeding 81% irrespective of conversion level. Moreover, the Pd@NMC catalyst has remarkable long-term stability during a 200-hours test, which would enable promising industrial applications. Comprehensive characterizations and DFT calculation reveal that the selectivity of Pd@NMC catalysts are primarily governed by the N configuration of the N-doped carbon support, which are strongly sensitive to the catalyst thermal treatment temperatures. Graphitic nitrogen is shown to tailor the electronic properties of Pd sites to promote the desorption of ethylene intermediate from the catalyst, endowing the modified Pd surface with high catalytic selectivity. These results indicate that the quantitative regulation of catalytic performance by tuning the local environment and electronic properties of Pd sites is a promising method, providing a solid foundation for designing chemoselective and long-lived Pd-based hydrogenation catalysts.

Automated summary

Efficient and sustainable catalysts for semi-hydrogenation of acetylene are crucial but difficult to design. This work presents a novel strategy using wheat flour as a support precursor to fabricate a well-performing Pd-based catalyst (Pd@NMC) with superior selectivity exceeding 81% for ethylene purification. The catalyst also exhibits remarkable long-term stability during a 200-hour test, showing promise for industrial applications.