Promotional effect of nitrogen-doped and pore structure for the direct synthesis of hydrogen peroxide from hydrogen and oxygen by Pd/C catalyst at ambient pressure

Abstract

Nitrogen-doped porous carbon is potential support for directly synthesizing H2O2 from H2 and O2. Here, density functional theory (DFT) was used to study the effect of N-doped porous carbon on H2O2 directly synthesized. The theoretical calculation results showed that N-doped improved H2O2 productivity and H2 conversion by increasing the dispersion of Pd nanoparticles and the Pd0/Pd2+ ratio. However, N-doped decreased H2O2 selectivity by reducing oxygen's dissociation energies. The experimental results showed that adjusting the pore structure of N-doped porous carbon could improve the adverse effects of N-doping for H2O2 selectivity. The H2O2 productivity and selectivity of Pd/C catalyst with a macropore-mesoporous-microporous hierarchical porous structure were up to 328.4 molH2O2·kgcat-1·h−1 and 71.9 %, respectively, at ambient pressure. The macropore structure enhances the transfer and diffusion performance of the catalyst and effectively inhibits the effect of N-doping on OO bond dissociation, which improves H2O2 productivity and selectivity. This research provides a possible solution for designing a high-performance Pd/C catalyst to directly synthesize H2O2 from H2 and O2 at ambient pressure.