The Preparation And Performance Of Ru-based Catalyst For Hydrogen Generation From Sodium Borohydride Methanolysis

Hydrogen is a safe,clean renewable energy source and it has been used in all aspects of industry,especially in proton exchange membrane fuel cells system(PEMFC).One of the key factors limiting the industrialization of fuel cells is a safe and efficient hydrogen storage system.At present,the hydrogen supply system for on-board fuel cells is compressed hydrogen storage.This hydrogen storage method has a very low hydrogen storage density and requires extremely high pressure,with certain risks.Therefore,it can not meet the demand of hydrogen for fuel cells vehicles.Sodium borohydride(NaBH4)is a substance with a high hydrogen storage mass density(10.8 wt.%)and is stable in alkaline solution.It can react with methanol for continuous hydrogen production at room temperature and appropriate catalyst conditions.Therefore,the study of high performance and controllable catalysts has become a key factor in the development for NaBH4 methanolysis.In this paper,the preparation and hydrogen generation test of Ru-based catalysts were studied.The main contents are as follows:(1)Ru-Fe bimetallic alloy nanoparticle catalyst(Ru-Fe/GO)was prepared by chemical reduction method on graphene oxide prepared using Hummers modified method.The effect of catalyst components on hydrogen generation rate for NaBH4 methanolysis was investigated.When Ru:Fe is 6:1,the catalytic activity is the highest,and the average rate is about 473 mL min-1·g-1.The effect of temperature on reaction rate is also discussed,and the activation energy is 59.33 kJ·mol-1 based on the data.(2)Ru-Ni/Ni foam catalysts with a spongy hollow structure were prepared by a combination of electroless plating and electroplating.The influence of Ru-Ni molar ratio on the morphology and activity of the catalysts was investigated.When the molar ratio of Ru:Ni was 3:1,the average reaction rate of catalytic methanolysis is the highest,about 360 mL·min-1·g-1.The activation energy is only 39.96 kJ·mol-1.After 5 cycles,the catalytic activity of the Ru-Ni/Ni foam catalysts still remains 75%of the original value,which indicates that Ru-Ni/Ni foam catalyst prepared by a combination of electroless plating and electroplating has a good stability.(3)NiO-Ni foam composite carrier was synthesized by hydrothermal method,and the Ru metal was supported by electroplating method to prepare Ru/NiO-Ni foam catalyst.The preparation conditions of Ru/NiO-Ni foam(RuC13,(NH3)2SO3 and current)were optimized on the morphology and catalytic activity of the catalyst.The kinetic results were further discussed,and the activation energy of NaBH4 methanolyasis catalyzed by Ru/NiO-Ni foam was calculated to be 42.33 kJ·mol-1.