Preparation Of N, Co Doped Carbon Materials And Their Catalytic Performance For Hydrogen Energy Efficient Utilization

The rapid consumption of fossil energy has caused humanity to face enormous environmental pollution and energy depletion.The development and use of clean sustainable energy is the fundamental way to solve energy and environmental problems.Solar energy and wind energy have the advantages of large scale and cleanness,but their discontinuity and instability limit their large-scale application.The use of fuel cells to store them is an effective method to solve their application bottlenecks,in which the cathode oxygen reduction reaction?ORR?is a key factor restricting its development.Hydrogen is also a clean energy carrier,but the effective and controlled release of hydrogen from hydrogen carriers is a problem that hydrogen utilization needs to solve.The availability of high efficiency catalysts is a key factor for ORR and hydrogen production reactions.The following two aspects of research have been conducted on the acquisition of high-efficiency catalysts.In the first part,the N-doped biomass carbon material MFBC filled with g-C₃N₄was obtained by the steps of hydrothermal,chemical activation and carbonization.The nanocarbon is used for catalyzing ORR with good effect.Under alkaline conditions,the initial potential is 0.95 V,the half-wave potential is 0.77 V,and the number of transferred electrons is 3.2.Compared with 10%Pt/C,the stability is good and the methanol tolerance is strong.The synthesis process includes dilute phosphoric acid assisted hydrothermal partial carbonization,KHCO₃ assisted high temperature pyrolysis carbonization,nitric acid soak surface activation,and melamine pyrolytic nitrogen doping.Finally,the nitrogen-filled g-C₃N₄nitrogen-doped biomass carbon material MFBC is obtained.The information of its morphology,pore structure,electronic structure and so on are purchased through atomic force microscopy?AFM?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,X-ray photoelectron spectroscopy?XPS?,Raman spectroscopy?Raman?,X-ray diffraction?XRD?.In the second part,a combination of one-pot boiling and pyrolysis was used to prepare a Co-modified N-doped nano-carbon composite PF5-I with a structure similar to pitaya pulp.The material is used to catalyze the hydrogen decomposition performance of sodium borohydride and ammonia borane.The hydrogenation rate of sodium borohydride and ammonia borane is 3998 and 4677 mL·min^-1·g_Co^-1respectively under self-stirring conditions at 25°C.The self-stirring using the magnetic properties of the material itself is more active than the magnetic stirring.The preparation process includes cobalt salt,citric acid and resorcinol,formaldehyde and other phenolic resin-coated Co coordination polymers?CPs?,which are pyrolyzed to obtain carbon-coated cobalt nanoparticles,in order to improve their catalytic activity.The material is oxidized in the air to form a Co-based nanocarbon composite in which Co and cobalt oxide coexist.The obtained materials were characterized by SEM,TEM,XPS,Raman,XRD and the like.In summary,the synthesis of nitrogen-doped nano-carbon materials and their catalytic properties for ORR and chemical hydrogen production provide new ideas and references for the design and preparation of such catalysts.