Effect Of Noble Metal Compounds/CoB Mixed Catalyst On The Hydrogen Release Property Of NaBH₄

Sodium borohydride has become the focus of many hydrogen energy researchers because it has high hydrogen storage density,high stability and its catalytic hydrolysis reaction is simple and easy to control.Cobalt boride is one of the most promising catalysts in the hydrolysis of sodium borohydride.However,the biggest drawback of cobalt boride is the irreversibility of the hydrolysis reaction.In addition,the reaction will produce too much heat and the rate will be too rapid so that the reaction can not be controled when the cobalt boride is used independently.Therefore,the aim of this paper is adding other materials into cobalt boride to form a new catalyst to improve its catalytic performance.This experiment mainly introduced five precious metal compounds,Ce?SO₄?₂?4H₂O,Ce Cl3?7H₂O,Ag2SO4,La Cl3?7H₂O and Sr CO3,were mixed respectively with Cobalt boride in different proportions to form five catalysts.The influence of catalyst on the properties of hydrolysis of sodium borohydride was studied by controlling the catalyst content from 3 wt% to 5 wt%.At the same time,the amount of hydrogen release and the rate of hydrogen release of sodium borohydride in each catalyst system were compared and analyzed.Water replacement method was carried out in this experiment in order to explore the hydrohysis behavior of Sodium borohydride.The experimental results show that the doping concent of noble metal compounds has a significant influence on the properties of hydrolysis of sodium borohydride.Uunder the same conditions,the amount of hydrogen release of sodium borohydride increases firstly,and then decreases with the decreases of noble metal content of the mixed catalyst.And the rate of hydrogen release of sodium borohydride increases gradually with the decreases of noble metal content of the mixed catalyst.In all the systems studied,the maximum amount of hydrogen release of sodium borohydride is 2450ml/g when the catalyst content is 5wt% and doping ratio is 3:7 in the Sr CO3/CoB system.The maximum the rate of hydrogen release of sodium borohydride is 3529.41ml/g?min when the catalyst content is 5wt% and doping ratio is 3:7 in the Ce Cl3?7H₂O/CoB system.