Preparation Of Ternary Cobalt-Based Nanomaterials And Their Catalytic Performance For Hydrogen Production

In recent decades,with the continuous consumption of fossil energy such as coal,oil and natural gas,and the serious damage to the ecological environment,people's desire for green energy has become stronger and stronger.Hydrogen energy occupies an important position in new energy with its unique advantages such as cleanliness and renewable energy.Ammonia borane?NH₃BH₃?is one of the more promising hydrogen storage materials due to its higher hydrogen storage content?19.6 wt%?,high stability and non-toxicity.NH₃BH₃ can release hydrogen by means of hydrolysis,but in this process,it must have the participation of a catalyst to achieve a controlled preparation of hydrogen.Previously,the most widely studied materials were precious metal catalysts,but their high cost and limited reserves limited their wide application.Therefore,non-precious metal catalyst materials have attracted much attention due to their low cost and abundant reserves.In this essay,the electroless plating method was used to successfully prepare ternary cobalt-based nano-catalyst materials with good catalytic activity on different substrates,and the catalytic hydrogen boron hydrolysis performance of ammonia borane was studied.The prepared materials were characterized by scanning electron microscope?SEM?,atomic force microscope?AFM?,transmission electron microscope?TEM?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,inductively coupled plasma mass spectrometry?ICP-MS?and inductively coupled plasma emission spectroscopy?ICP-OES?.The main research contents and results are as follows:1.The ternary Co-Mo-B nano-materials were successfully prepared on the copper substrate by electroless plating,and their catalytic performance for hydrogen production from NH₃BH₃hydrolysis was studied.By optimizing the process conditions of electroless plating,the following conclusions were reached:When the pH of the plating solution was adjusted to 11.0,the ternary Co-Mo-B nanomaterials prepared had the smallest particle size of 4.3 nm,which catalyzed the liberation of NH₃BH₃.The hydrogen rate was 5818.0 mL·min^-1·g^-1_cat and the activation energy was 55.2 kJ·mol^-1.2.The ternary Co-Mo-B nano-materials were successfully prepared on the foamed Ni substrate by electroless plating method,and the catalytic performance of NH3BH3 for hydrogen production was studied.By optimizing the process conditions of electroless plating,the following conclusions are drawn:When the ratio of Co²⁺to MoO₄^2-in the plating solution is adjusted to 1:1,the particle size of the ternary Co-Mo-B nanomaterials prepared is the smallest,which is at 37 nm,the rate of hydrogen liberation from NH₃BH₃ water is 5331.0 mL·min^-1·g^-1_cat,and the activation energy is 45.5 kJ·mol^-1.3.The ternary Co-W-B nano-materials were successfully prepared on the foam sponge substrate by electroless plating,and their catalytic performance for NH₃BH₃ hydrolysis to produce hydrogen was studied.By optimizing the process conditions of electroless plating,the following conclusions were reached:When the pH of the plating solution was adjusted to 12.5,the particle size of the ternary Co-WB nanomaterials prepared was the smallest at 67.3 nm,which catalyzed the hydrogen liberation rate of NH₃BH₃.It is 3327.7 mL·min^-1·g^-1_cat and the activation energy is 32.2 kJ·mol^-1.After 5 cycles of testing,its hydrogen release rate declined,but still maintained 78.4%of its initial value.This shows that the catalytic material has better cycle stability and reusability.