Abstract
Pd/C nanocatalyst with high turnover frequency (TOF) for hydrogen generation from the formic acid (FA)–sodium formate (SF) mixtures was prepared via an ex situ reduction of PdCl2 used formate in the presence of citric acid. The morphology and property of the Pd/C catalyst before and after decomposition of FA–SF mixture were characterised using transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, X-ray diffractometer and Fourier transform infrared spectrometer. Over this Pd/C catalyst, a TOF of 228.3 h−1 was observed for a FA–SF mixture with a FA/SF ratio of 1:9. The observed TOF was the highest ever reported for heterogeneous Pd/C catalysts. The deactivation of the Pd/C catalyst was attributed to desorption of citric acid, reduction of PdII content and adsorption of CO. Washing and drying could partially recover the activity of the Pd/C catalyst.
The formic acid (FA)–sodium formate (SF) mixture with a FA/SF ratio of 1/9 gives a turnover frequency of 228.3 h−1 over a Pd/C catalyst prepared via an ex situ liquid phase reduction in presence of citric acid. [Display omitted]
•A new strategy for preparing highly active Pd/C catalyst was established.•The highest turnover frequency of 228.3 h−1 was obtained over this Pd/C catalyst.•The optimal formic acid/formate ratio with highest activity was 1/9.•Desorption of citric acid, adsorption of CO and reduction of PdII/Pd0 ratio deactivated the Pd/C catalyst.•Washing and drying partially recovered the activity of the Pd/C catalyst.