Atmospheric-pressure dielectric barrier discharge cold plasma for synthesizing high performance Pd/C formic acid dehydrogenation catalyst

HCOOH is a cheap, non-toxic, ease of storage and transportation, and abundant renewable source for generating hydrogen. Activated carbon supported palladium (Pd/C) catalysts have drawn increasing research interest due to their high performance toward HCOOH dehydrogenation and ease of recycle after deactivation. In this work, atmospheric-pressure (AP) dielectric barrier discharge (DBD) cold plasma has been employed to synthesize Pd/C-P catalyst by using PdCl2 as Pd precursor. For comparison, commercial Sigma-Aldrich Pd/C catalyst is adopted as the reference. Both cold plasma synthesized Pd/C-P and commercial Pd/C catalysts exhibit high performance for HCOOH dehydrogenation, and no CO is detected. The total volume of generated H-2 and CO2 over Pd/C-P is 317 ml, which is 1.12 times as that of commercial Pd/C (282 ml). The catalytic stability of Pd/C-P is much superior to the commercial Pd/C catalyst. Catalytic activity of Pd/C-P has been decreased to 59.6% and 50.2% after the second and third reaction cycle, respectively, in comparison with the first cycle. However, they have been decreased to 16.3% and 8.9%, respectively, for commercial Pd/C. Various characterization techniques have been adopted to discuss the influence mechanism. The high catalytic activity of Pd/C-P is mainly attributed to the small size of Pd nanoparticles. The high catalytic stability of Pd/C-P is ascribed to the strong metal-support interaction induced by cold plasma and HNO3 pre-oxidation treatment, which leads to less decrease in Pd/C atomic ratio, Pd leaching, and stabilizes the size of Pd nanoparticles. In conclusion, the Pd/C-P catalyst exhibits much higher catalytic activity and stability than the commercial Pd/C, which has theoretical significance and practical application value.