Preparation Of Supported Ni-based Bimetallic Catalysts By Electroless Plating And Their Catalytic Performance For Hydrogen Production

In the 21st century,the global energy field is facing great challenges.Energy consuming way mainly by fossil fuels has led to environmental and ecological destruction Therefore,it is very urgent to find other clean energy.Hydrogen,as a renewable energy source or energy carrier,has some advantages such as non-toxic,bountiful in supply,producing highly thermal efficiency,none greenhouse gases emissions,etc.Large-scale development of hydrogen energy has a close relationship with the clean and efficient method of hydrogen production.Hydrogen iodide decomposition and sodium borohydride hydrolysis are two highly characteristic hydrogen production reactions.The former is the hydrogen production step in the iodine-sulfur thermochemical water-splitting cycle.The other one,NaBH4 itself has a hydrogen storage of 10.8 wt%.Reacting with water,the amount of hydrogen produced is twice than its own storage.Catalyst is the key to the occurrence of these two hydrogen production reactions.In this paper,these two reactions are used as probe reactions to evaluate the catalytic performance of the supported nickel-based catalysts prepared by the electroless plating methodIn this paper,nickel-based bimetallic catalysts(Ni-Mo-P、Ni-Mo-B)with a homogeneous metal distribution and excellent corrosion resistance were synthesized through electroless plating method.Effects of the preparation factors(such as,kinds of activating metals,kinds of reductants,contents of the second metal Mo,plating time)on the structure and catalytic property of the supported Ni-Mo bimetallic catalysts were deeply studied.And then,the preparation rules of ideal catalysts were obtained.Specific experimental procedures are as follows:firstly,the carrier(activated carbon)was activated by the impregnation-reduction method.Pd and Ir were respectively selected as the active metal to activate the carrier.And then the activated carrier was added into the bimetallic Ni-Mo plating bath,using potassium borohydride or sodium hypophosphite as the reducing agent.Effects of the Mo contents and the plating time on the plating results were investigated.Secondly,the physical-chemical properties of the catalysts were characterized by the methods of XRD,TEM etc.And the catalytic performances were tested by two different hydrogen generation reactions,the decomposition of HI and the hydrolysis of sodium borohydride respectively.Finally,we had the optimal preparation conditions of the catalysts,through which the highly stable,active and recyclable nickel-based bimetallic catalysts were obtained.The results of XRD and TEM characterization show that the active metal is highly dispersed on the activated carbon carrier.After the reactions,although the supported metal particles have become larger,the sizes are still much smaller than the supported particles of the pure Ni catalysts,indicating that the addition of Mo increases the stability of the catalysts.After thoes two hydrogen production reactions,the optimum catalyst composition was found to be 10%Nil.0%Mo/AC.The above research results provide experimental reference for the further development of high-activity catalysts by electroless plating method.