Study On The Catalysts Of Formic Acid Electro-Oxidation And Decomposition For Hydrogen Generation

This thesis mainly studies both the catalysts of formic acid electro-oxidation and the catalysts for formic acid decomposition,including the catalyst designing,catalyst preparation and catalyst characterization.Herein,we developed a novel and facile strategy for the synthesis of nitrogen-doped carbon black supported Pd nanoparticles with superior electrocatalytic activity by hydrothermal treatment of oxidized carbon with ammonia.Pd nanoparticles supported on nitrogen doped carbon black(Vulcan XC-72R)with two different levels of doping were prepared by microwave-assisted ethylene glycol reduction process and used as catalyst for the formic acid electro-oxidation(FAEO).Compared to the palladium on carbon(Pd/C-H)catalyst(41.3m2 g-1),both the Pd/N-C(high)with higher N content and the Pd/N-C(low)with lower N content catalysts showed larger electrochemically active surface area(49.9m2g-1and 41.5 m2g-1),which endowed the nitrogen-doped catalysts excellent electrocatalytic activity for formic acid electro-oxidation.The peak current density of the Pd/N-C(high)and the Pd/N-C(low)catalysts were 1294 and 1019 m A mg-1Pd,which was about 1.31 and 0.82 times higher than the Pd/C-H catalyst(560 mA mg-1Pd),respectively.Results indicate that the different nitrogen doping contents in Pd/N-C catalyst affect the performance of FAEO significantly.A higher N content facilitates the uniform dispersion of Pd nanoparticles on carbon black with narrow particle size distribution.Furthermore,the electrochemical results shows the catalysts with higher N-doping content possesses higher catalytic activity and long-term stability for FAEO.We also studied the catalysts for the decomposition of formic acid.Pd-Pt/C and Pd/C were prepared by microwave-assisted ethylene glycol reduction process and used as catalyst for the formic acid decomposition.In order to characterize the properties of the prepared Pd-Pt/C and Pd/C,X-ray diffraction(XRD)and X-ray photoelectron spectrum(XPS)were carried out to characterize the surface properties,particles dispersion and particles size of the catalysts.0.1wt%Pt has been proved doping successfully by Inductively coupled plasma mass spectrometry(ICP-MS).Through the analysis of formicacid decomposition tests,we found that Pd-Pt/C showed a better catalyst activity than Pd/C in the same range of particle size for the formic acid decomposition.At last,We also build a calculating formula of TOF used in the characterization of catalyst activity for the formic acid decomposition.