Study On Co-based Oxide Composite Nano-catalysts For Hydrogen Generation From Sodium Borohydride Hydrolysis

Nowadays,with the rapid development of economic,energy consumption is increasingly enhancing,in contrast,environmental concerns are also facing a severe problem.The sustainable economic growth and environment pollution are two irreconcilable contradictions if we continue to use fossil fuels only.More and more scientists from various countries have tried to discover or creat an environment-friendly,high-efficiency and safe alternative method to solve this issue.Among all of the selected potential energies,hydrogen as the cleanest energy is widely concerned.Hydrogen can be directly used by PEM fuel cells directly,and the hydrogen could be easily transformed into electricity which could be widely met various energy dissipation device.However,there are still some problems that should be further expored,such as safety problem,hydrogen storage efficiency,and continuous and convenient hydrogen system.NaBH4 has many advantages,like it has a large capacity of the theory hydrogen storage,high energy density,safe and realiability,etc.Therefor NaBH4 becomes the central point of the study of creating H2 at home and around.At room temperature,the NaBH4 stored in the natural environment will undergo spontaneous hydrolysis reaction to produce a small amount of hydrogen.The focus of the research is to prepare a high efficiency,low cost,easy to recycle,recyclable catalyst for the hydrolysis of NaBH4 solution.Precious metals(such as Pt,Pd,Ru,Rh)act as catalysts for hydrolysis of NaBH4 has exhibited good performance,but due to the use of the high cost of the noble metal,limiting the application of hydrogen energy.Therefore,the research and development of NaBH4 hydrolysis catalyst which can be put into mass application becomes an urgent problem to be solved.Many scholars at home and abroad have found that the catalytic effect of Co is very significant,and the reaction process is highly efficient and controllable,and this element exists widely in the earth's crust.Therefore,this paper focuses on Co oxide based forms of preparation of nano-catalyst,and launched a series of research on the catalytic performance of NaBH4 hydrolysis,and characterized by means of microstructure of the catalyst for further analysis research.Specific research contents are as follows:1.In this paper,Pt derivative of PtO modified LaCoOx nano composite catalyst(PtO/LaCoOx)were prepared by a one-step in situ green reduction method.The catalyst for the amorphous catalysts.Due to the electronic interactions,composition of La and Co showed interesting properties.La plays a buffer role in the reduction of Pt ions,so as to form the PtO.PtO was regarded as a highly reactive center to enhance the catalytic activity.A series of different content of Pt catalysts was prepared,found that with the content of Pt at 7.5 wt%,the maximum average rate of hydrogen evolution at room temperature can reach 7091 mL min-1 g(catalyst)-1,and activation energy value Ea=57.50 kJ mol-1.Compared with the supported catalysts,the process of the preparation of PtO/LaCoOx is simple and in a short-period.The prepared catalyst was characterized by XRD,XPS,TEM,SEM,EDS and so on.2.Ultra-thin anatase TiO2 nanosheets were synthesied by a hydrothermal reaction.In no addition of stabilizer and surfactant,the Pt/CoO,-TiO2 nanoparticles catalyst was prepared using NaBH4 as a reducing agent at room temperature.The high dispersion and enrichment of Pt can improve the catalytic performance.Through the comparison of catalytic properties of pure metal Pt/CoOx nanoparticles,nano Pt/CoOx complex supported on TiO2 showed a strong performence,the highest average hydrogen evolution rate of up to 9138 mL min-1 g(catalyst)-1.At the same time,the TiO2 and the catalysts were characterized,and the catalytic durability and activation energy of NaBH4 hydrolysis were analyzed.3.First,the amino functionalized silica nanospheres were synthesized(f-SiO2).Second,based on the principle of electrostatic adsorption,the complex formed by the noble metal Ru and Co oxide was successfully loaded on the functionalized SiO2 nanospheres,then the Ru/CoOx-f-SiO2 nano-composite catalyst was obtained.Among them,Co oxide as an active component plays an important role in improving the performance of the catalyst.We tested the performance of different Ru mass fraction of catalysts,found that with only 2.5 wt%of quantum-sized Ru dots exhibit an extremely high catalytic activity and the average hydrogen generation can reached 6093 mL min-1 g(catalyst)-1 at room temperature,the low activation energy of Ea=38.29 kJ/mol.The f-SiO2 nano sphere provides a larger specific surface area,which plays a key role in the uniform dispersion of the active components of Ru/CoOx,so as to improve the stability of the catalyst.The synthetic functional groups,micro morphology,crystal structure,element valence and distribution as well as the actual metal content of catalysts were characterized and measured by FT-IR,TEM,XRD,XPS,EDS and ICP,respectively.