Preparation And Performance Study Of Hydrogen Generation Catalysts For Sodium Borohydride Methanolysis

Storage and transportation of hydrogen are still obstacles to the development of proton exchange membrane fuel cell(PEMFC).At present,the hydrogen supply system of vehicle fuel cell is mainly gas cylinders,and thus physical hydrogen storage method suffers from extreme processing conditions and entail sizable safety risks.Hence,to solve the problem,the concept of chemical hydrogen storage method has been proposed and attracted intense attentions.Sodium borohydride(NaBH4)has been considered as a potential candidate for hydrogen storage in the light of its high gravimetric density(10.8 wt%),environmentally friendliness,and potentially safe operation.Hydrogen generation from NaBH4 methanolysis is regarded as an emerging technology,which becomes a candidate of hydrogen sources for portable fuel cell.The preparation of efficient and stable catalyst is the key issue of developing NaBH4-CH3OH hydrogen generation system.In this paper,the preparation and performance of hydrogen generation catalysts for sodium borohydride methanolysis were studied.The main contents are as follows:(1)A series of carbon black supported bimetallic Ru-Co nanoparticles catalyst(Ru-Co/C)were synthesized via the chemical reduction of corresponding metal precursor in ethylene glycol,for H2 generation from NaBH4 methanolysis.The effects of catalyst components on the catalytic activity were studied in detail.Significantly,the highest H2 generation rate is observed in the case of Ru-Co/C catalyst with Ru/Co ratio of 5,achieving 9.36×103 mL min-1·g-1 at 25 ?.The kinetic behavior of the catalyst was investigated.The apparent activation energy of the catalyst was as low as 30.1 kJ mol-1.And its structure-activity relationship was explored.(2)Ni foam supported Co-P alloy catalysts were synthesized by electroless plating method.Effects of preparation conditions on morphology and performance of the catalysts were studied in detail.And the optimum conditions for the catalyst were studied.Co-P catalysts composed of nanoflowers are successfully obtained under optimized conditions.The as-prepared Co-P/Ni foam catalyst with hierarchical flower-like shape shows significantly enhanced catalytic activity during methanolysis of NaBH4,affording hydrogen release rate of 3.52×103 mL min-1·g-1 at 25 ?.(3)Firstly,CNTs/Ni foam support was synthesized by chemical vapor deposition method.Then,Co-P/CNTs/Ni foam catalysts were synthesized by electroless plating method.The morphology and structure of the novel nanomaterial are well characterized.The preparation of the support and catalyst were optimized.The highest H2 generation rate is observed under optimized conditions,achieving 2.3×103 mL·min-1·g-1,and the apparent activation energy of the catalyst was 47.74 kJ·mol-1.