Preparation Of Nickel-Doped Rare Earth Oxide Nanoparticles And Study On Hydrogen Production Performance Of Decomposed Hydrazine Hydrate

At present,environmental and energy problems are becoming increasingly serious..Hydrogen energy received wide attention as a clean and efficient new energy.Hydrazine hydrate?N₂H₄ H₂O?is a liquid hydrogen storage materials,it contains high levels of hydrogen and is easy to store and transport.It was found that hydrazine hydrate can be selectively decomposed to produce N2 and H₂ under the action of catalyst,which is beneficial to the application and development of hydrogen energy.In this paper,several Ni-REO?rare earth oxide?catalysts for the catalytic decomposition of hydrazine hydrate were prepared by liquid-phase co-reduction.In this method,Ni1-x-?REO?x catalyst is obtained by co-reduction at room temperature with the salt of nickel and rare earth elements as the percursor and sodium borohydride as the reducing agent.And the prepared catalyst was subjected to hydrazine hydrate catalytic decomposition test.?1?At room temperature,Ni-Nd₂O₃ nanoparticles were prepared by liquid-phase co-reduction method.The morphology and composition of Ni-Nd₂O₃ particles were characterized by X-ray diffraction?XRD?,transmission electron microscopy?TEM?,energy dispersive spectroscopy?EDS?and X-ray photoelectron spectroscopy?XPS?.And the catalytic decomposition of hydrazine hydrate was investigated.The results show that Nd₂O₃ has an effect on the crystal structure and morphology of nickel,and improves the dispersion of the catalyst.Under the temperatre of 70?,Ni0.94-?Nd₂O₃?0.06 showed the best performance of hydrazine hydrate decomposition,the hydrogen selectivity was 99%,the conversion frequency TOF value was 52.17h^-1.The catalytic performance of the catalyst in the repeated experiments was almost the same,and the stability of the catalyst had excellent performance;?2?Ni-La₂O₃ nanoparticles were prepared by liquid-phase co-reduction method at room temperature.The morphology and composition of Ni-La₂O₃ particles were characterized by XRD,TEM,EDS and XPS,and the catalytic decomposition of hydrazine hydrate was investigated.It was found that La₂O₃ had an effect on the crystal structure and morphology of nickel,which could effectively reduce the particle size of nanoparticles.Under the condition of 70 ?,Ni_0.8-?La₂O₃?_0.2 nanometer catalyst has the best hydrazine hydrate decomposition performance,the hydrogen selectivity is 95%,the conversion frequency TOF value is 61.76h^-1.The results of seven repeated catalytic experiments show that the catalyst has high stability;?3?Alkaline environment can improve the selectivity of hydrazine hydrate decomposition reaction.The addition of different metal ions during the synthesis of the catalyst may also affect the composition and structure of the catalyst and cause changes in the catalytic performance.It was found that the addition of NaOH solution in the reaction system can improve the H₂ selectivity of hydrazine hydrate decomposition reaction,but it is not active when using NaOH alone to decompose hydrazine hydrate.The addition of another metal salt solution to the catalyst precursor solution resulted in the reduction of the catalyst,which had no significant effect on the reaction performance of hydrazine hydrate decomposition.