Low-temperature plasma-assisted preparation of graphene supported palladium nanoparticles with high hydrodesulfurization activity

In this work, a novel strategy to obtain the graphene-supported palladium catalyst for the hydrodesulfurization of carbonyl sulfide (COS) in coal gas is presented. By employing the low temperature dielectric barrier discharge (DBD) plasma, well-dispersed Pd nanoparticles with particle size of about 2 nm supported on graphene sheets (PL-Pd/GS) have been synthesized through a facile one-step route, in which the graphite oxides and PdCl2 were simultaneously reduced in hydrogen plasma. The as-prepared PL-Pd/GS catalyst shows higher catalytic efficiency in the COS hydrogenation, compared to a traditional Pd/C catalyst, as well as Pd/GS reduced by hydrogen at high temperature or by ethylene glycol reduction in liquid phase. Characterizations using XRD, FT-IR, Raman, and HRTEM techniques reveal that the improved performance of PL-Pd/GS for COS conversion is attributed to small size and uniform dispersion of Pd nanoparticles on graphene sheets resulting from the efficient low temperature treatment in DBD plasma. This finding inspires the in situ preparation of various metal-graphene sheets catalysts by taking advantage of plasma, and paves a new avenue to make use of graphene sheets as a support material to improve catalytic activity.