Synthesis Of Supported Non-noble Metal Catalysts And Their Catalytic Performance For Dehydrogenation Of Ammonia Borane

In the 21th century,energy shortage has become a serious issue.To find a clean and sustainable energy system has become the best way to solve these problems.Hydrogen is regarded as an ideal energy carrier for its abundant resources,high energy density and zero emission.Although the content of hydrogen is extremely high on the earth,most of them are in the form of compounds which are unavailable.They need to be converted into hydrogen gas to be used.Therefore,the preparation of hydrogen gas has become one of the key factors to solve the practical use of hydrogen.Ammonia borane(NH3 ·BH3,AB)is an ideal hydrogen carrier for its high hydrogen content of 19.6 wt.%,and good chemical stability.By adding a proper catalyst,AB can release H2 by hydrolysis or methanolysis.Finding a suitable low-cost catalyst has become the key of the practical application of AB.This research mainly works in hydrolysis and reversible methanolysis of AB.Firstly,we successfully immobilized non-noble trimetallic Cu-Ni-Co nanoparticles into the pores of MIL-101 using a simple solvent evaporation method to obtain Cu-Ni-Co@MIL-101 nanocatalysts.Then we varied the metal molar ratios to improve their catalytic activity on AB hydrolysis.Secondly,we use nitrogen-doped carbon(NC)as substrate to support trimetallic Cu-Ni-Co nanofilm and obtained a 2D nanosheet structure for the Cu-Ni-Co/NC nanocatalyst.From the varieties of the metal molar ratios and supports,the Cu-Ni-Co/NC possess excellent catalytic performance for AB methanolysis.The non-noble trimetallic Cu-Ni-Co@MIL-101 catalyst for AB hydrolysis is studied.We confine the Cu,Ni or Co nanoparticles into the structure by solvent evaporation method,and the obtained catalyst possess high catalytic activity.When Cu:Ni:Co = 8:1:1,the catalyst Cu0.8Ni0.1Co0.1@MIL-101 exhibits superior catalytic activity with turnover frequency(TOF)value of 72.1 molH2 molcat-1 min-1,and no significant decline after 8 cycles.The 2D Cu-Ni-Co/NC nanocatalyst for AB methanolysis is also studied.By changing the metal ratios and substrates,when the molar ratios of Cu:Ni:Co = 8:1:1,and the precursor is urea,the catalyst Cu0.8Ni0.1Co0.1/NC(urea)shows the highest catalytic activity with turnover frequency(TOF)of 70.2 min-1 and no significant decline after 5 cycles.