Preparation Of Highly Active Cobalt-based Catalysts And Their Catalytic Properties For Hydrolysis Of Sodium Borohydride

Hydrolysis of sodium borohydride for hydrogen production requires highly active catalyst participation.The noble metal catalyst has high catalytic activity,but its economic cost is high and its resource reserves are few,which makes it very important to develop non-noble metal catalyst.Among many non-noble metal catalysts,cobalt based alloy catalysts are widely studied because of their advantages of high catalytic activity,abundant resources and low cost,but they have the disadvantages of poor stability and easy agglomeration.This paper starts from a highly stable support for loading cobalt-based catalysts to improve their catalytic performance.Three loaded cobalt-based materials,BC/Co-B,Co-B/MS and CeO₂/Co-B,were prepared using bacterial cellulose-derived carbon,melamine sponge carbon materials and rare earth metal oxide CeO₂as carriers.The main research contents are as follows:（1）The surface of bacterial cellulose has abundant functional groups.Bacterial cellulose was carbonized at high temperature（75℃）to produce bacterial cellulose-derived carbon（BC）.Obtained BC has high specific surface area and good adsorption on metal ions,which was used as a carbon carrier to reduce inorganic cobalt salt at room temperature using sodium borohydride to prepare BC/Co-B nanocomposite catalysts.The results showed that the high hydrogen production rate of 3887.1 m L·min^-1·g^-1was obtained at 30℃,and the activation energy was 56.37 k J·mol^-1,and the initial maintainable activity was 37.5%after 5 cycles.（2）The porous carbon doped with nitrogen has good hydrophilicity and is easy to be supported by metal catalyst.Co-B/MS composite material was obtained by chemical reduction using melamine sponge carbon material as carrier.Co-B/MS material contains a large number of mesopores and exhibits extremely high catalytic activity during the hydrolysis of sodium borohydride to produce hydrogen.The results showed that the activity of the BC/Co-B catalyst prepared with different carbon doping amount of melamine sponge carbon material（MS）was the best when the MS carrier loading was 0.05g,the hydrogen production rate was 4180.76 m L·min^-1·g^-1at 30℃,the activation energy was 63.85 k J·mol^-1,and the cycling performance was good.（3）Rare earth oxides can effectively improve the corrosion resistance of the catalyst.In this paper,CeO₂/Co-B nanocomposites with rod-like structure were prepared by using rare earth metal oxide CeO₂as carriers under low temperature ice bath conditions.As catalysts,this material has good activity during the hydrolysis of sodium borohydride.When the amount of substance ratio of inorganic cobalt salt to CeO₂carrier is 1,the CeO₂/Co-B catalyst has the highest activity,the hydrogen production rate is 2872 m L·min^-1·g^-1at 30℃,and it has very low activation energy(33.13 k J·mol^-1)and excellent cycling performance.