Preparation Of PVP-Stabilized Amorphous Alloy Nanocatalysts For Hydrogen Production From Methanolysis Of Ammonia Borane

Ammonia borane(NH3BH3,AB),as a solid hydrogen storage material,has drawn considerable attention for its excellent hydrogen storage capacity and stability.Studies have shown that ammonia borane can completely produce hydrogen in the presence of a suitable metal catalyst at room temperature or even low temperature.Therefore,developing suitable metal catalysts has become a hot topic.This paper selected nonnoble metals Cu,Co,Ni as the active components,and at the same time used polyvinylpyrrolidone(PVP)as the stabilizer and dispersant to prepare amorphous alloy nanocatalysts to achieve efficient hydrogen generation from methanolysis of ammonia borane.The main research work includes the following two parts:Firstly,a series of magnetically recyclable Co1-xNix(x=0,0.1,0.3,0.5,0.7,1)alloy catalysts were prepared by a simple liquid phase reduction method.The asprepared Co1-xNix/PVP nanocatalyst was performed by XRD,XPS,FT-IR,TEM and the results showed that the amorphous CoNi alloy catalysts were successfully synthesized.The synthesized catalysts were applied to the ammonia borane methanolysis,and the catalytic performance of the catalyst under optimal condition was explored.Experiments showed that when the molar ratio of PVP to catalyst was 5:1,and the molar ratio of Co to Ni was 7:3,the Co0.7Ni0.3/PVP catalyst had the highest catalytic activity with a TOF value of 35.3 molH2/(molcatalyst·min),the activation energy was 23.60 kJ/mol,and the catalyst can still maintain 91.2%initial catalytic activity after 8 cycles.Secondly,adopting the same liquid phase reduction method and introducing Cu metal to prepare CuCoNi/PVP alloy catalysts,XRD,XPS,TEM and other instrumental techniques were tested.The results proved that the synthetic method can prepare amorphous CuCoNi ternary alloy catalyst quickly.In the test of catalytic activity for AB methanolysis,compared with bimetallic catalysts,ternary CuCoNi catalyst exhibited more excellent catalytic activity.The effects of different metal molar ratios on the catalytic activity of catalysts were explored.The results showed that PVPstabilized Cu0.4Co0.4Ni0.2 nanocatalysts had the highest catalytic activity at room temperature,and the TOF value can reach 46.1 molH2/(molcatalyst·min),The activation energy was 29.4 kJ/mol,and the catalyst maintained 93.6%initial catalytic activity after using 8 times.