КАТАЛІТИЧНА АКТИВНІСТЬ НАНОЧАСТИНОК НІКЕЛЮ В ПРОЦЕСІ ОТРИМАННЯ ВОДНЮ РОЗКЛАДОМ ГІДРАЗИНУ

Abstract

Catalytic systems based on nickel nanoparticles (NiNPs) can be used to reduce the nitroaromatic compounds with sodium borohydride, to obtain synthesis gas from reducing raw materials, etc. The mechanism of catalytic action of nickel in such processes is similar to the mechanism of action of Raney nickel, however, the nanosize of nickel particles makes it possible to create a much wider range of catalytic systems due to the use of various carriers. Research into the use of NiNPs in hydrogen generation processes deserves the special attention. In particular, it is known that the NiNPs are an effective catalyst for the decomposition of alkaline NaBH4 solutions. Another promising source of hydrogen is hydrazine hydrate, which has a high hydrogen capacity, solid reaction products are not formed during its decomposition, and it is also economically more profitable compared to NaBH4. Recently it was shown that in alkaline solutions of ethylene glycol in the presence of NiNPs, hydrazine is decomposed according to the reaction N2H4 -> N2 + 2H2, i. e., only nitrogen and hydrogen are reaction products. Therefore, the purpose of this work is to investigate the catalytic activity of NiNPs in the process of generating hydrogen by the decomposition of hydrazine. NiNPs were synthesized by the reduction of nickel acetate with hydrazine in an alkaline solution of ethylene glycol in the absence of surfactants. Using the SEM, EDX and XRD it was shown that the obtained NiNPs are spherical in shape with a size of 150-200 nm and do not contain nickel hydroxide residues. The catalytic activity of NiNPs in the process of hydrogen generation by decomposition of an alkaline solution of hydrazine in ethylene glycol was investigated using the volumetric method. It was shown that the rate of hydrogen evolution is 130 ml/min per 1 gram of catalyst, and the activation energy of the catalytic decomposition of hydrazine is 65 ± 2 kJ/mol.