Synthesis of nanoporous PdAg nanoalloy for hydrogen generation from formic acid at room temperature

Abstract A new one pot, surfactant-free, room temperature synthetic route based on coreduction of Pd 2+ and Ag + salt by ascorbic acid has been developed for the synthesis of Pd x Ag 1−x nanoparticles (NPs). The nanoporous structure of the Pd x Ag 1−x nanoalloy having spherical ligaments is confirmed by XRD, FESEM, EDX, TEM, HRTEM, SAED and XPS studies. The nitrogen adsorption–desorption isotherm (BET) of Pd x Ag 1−x NPs can be classified as type V which is characteristic of a solid with mesopores. Some of the Pd x Ag 1−x nanoporous nanoalloy catalyst thus prepared exhibit high activity towards H 2 generation with an extremely high selectivity and stability in formic acid (FA) dehydrogenation. The catalytic activity towards H 2 generation from FA followed the trend of Pd 0.5 Ag 0.5  > Pd 0.6 Ag 0.4  > Pd 0.67 Ag 0.33  > Pd 0.75 Ag 0.25  ≈ Pd. Rate of FA decomposition closely follow the first order kinetics. The recycle test results of the Pd 0.5 Ag 0.5 nanocatalyst show no significant decrease in catalytic activity over five cycles. The catalysts can be regenerated by simply rinsing with water followed by drying at room temperature. It is believed that this low cost, selective and efficient CO-free H 2 generation system at room temperature will promote its application in different devices like FA driven fuel cells.