Efficient dehydrogenation of a formic acid-ammonium formate mixture over AuPd catalyst.

A series of AuPd/C catalysts were prepared and tested for the first time for active and stable dehydrogenation of a formic acid-ammonium formate (FA-AF) mixture. The catalysts with different Au-to-Pd molar ratios were prepared using a facile simultaneous reduction method and characterized using transmission electron microscopy (TEM), high-resolution TEM, energy dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. It was found that the catalytic activity and stability of the AuPd/C catalyst was the best. The initial turnover frequency for the dehydrogenation of the FA-AF mixture over the AuPd/C catalyst can reach 407.5 h at 365 K. The reaction order with respect to FA and AF is 0.25 and 0.55, respectively. The apparent activation energy of dehydrogenation is 23.3 ± 1.3 kJ mol. The catalytic activity of the AuPd/C catalyst remains 88.0% after 4 runs, which is much better than the single Pd/C catalyst. The mechanism for the dehydrogenation is also discussed.