Plasma is a simple and effective method to prepare N-doped carbon materials and supported metal catalysts. In this work, Pd/C-C(NH3) and Pd/C-P(NH3) catalysts are prepared by heat treatment and cold plasma methods using Ar and NH3 as the working gas. The activity and stability of obtained catalysts are tested by formic acid dehydrogenation reaction. The results show that TOFinitial of Pd/C-P(NH3) is 527.1 h(-1) at 50 degrees C, and the HCOOH decomposition rate is about 89.2% at 4 h. The hydrogen production of Pd/C-P(NH3) when used in first and third cycle are 1.14 and 1.14 times than that of Pd/C-C(NH3), and 1.24 and 13.24 times than that of commercial Pd/C. Various characterization techniques are used to characterize the structure of the prepared Pd/C catalysts. The results indicate that NH3 plasma is milder than NH3 thermal treatment. The high activity and stability of Pd/C-P(NH3) are mainly due to the NH3 cold plasma effectively achieving N-doping of the carbon support, and Pd nanoparticles with a small size and high dispersion. Atmospheric pressure NH3 cold plasma provides an effective method to prepare high-performance Pd/C catalysts for HCOOH dehydrogenation and plays a guiding role in the preparation of high- performance carbon-supported noble metal catalysts. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.