Magnetic N-doped partially graphitized carbon-loaded Pd-Co alloy nanoparticles for efficient hydrogen production

Abstract

Liquid organic hydrogen carriers (LOHCs) are generally recognized as an important form of hydrogen storage. The low hydrogen release rate and high hydrogen release temperature limit the application of LOHCs. The PdCo alloy nanoparticles (NPs) loaded on magnetic N-doped partially graphitized carbon (PdCo/NGC) were prepared in an environmentally friendly manner by N2 glow discharge plasma method. Porous support carbon is prepared by calcining Zeolitic Imidazolate Frameworks-67 (ZIF-67) at 800 °C, which is not only magnetic but also N-doped and partially graphitized. PdCo NPs are uniformly dispersed on NGC with an average particle size of 4.0 nm. The plasma reduction method can effectively prevent the agglomeration of PdCo alloy NPs, which is an important guarantee for the small particle size of PdCo NPs. The uniform dispersion effect and charge transfer effect produced by the alloy structure of PdCo NPs improve the catalytic activity. PdCo/NGC shows excellent catalytic performance for dodecahydro-N-ethylcarbazole (H12-NEC) dehydrogenation. The complete conversion of H12-NEC is achieved at 180 °C for 6 h, the selectivity of N-ethylcarbazole is 97.87% and the dehydrogenation efficiency is as high as 98.79%. PdCo/NGC catalysts with a saturation magnetization of 25 emug−1 at room temperature can be effectively recovered under the action of an external magnetic field. They show superior catalytic stability, in which the dehydrogenation efficiency can still reach 93.60% after six cycles.