The photocatalytic performance of graphite carbon nitride (g-C₃N₄) is controlled by its microstructure, and the study of the relationship between precursor types and g-C₃N₄ microstructure will be an interesting problem. In this paper, the thermal decomposition kinetics were applied to search the reaction process of the two g-C₃N₄ catalysts coming from two precursors of melamine (MA) and dicyandiamide (DCDA). It can be found that unlike the transition process of DCDA to g-C₃N₄, the reaction of MA is less hindered, and it readily undergoes thermal decomposition, resulting in MA-g-C₃N₄ catalyst having fewer amino groups. This further causes a decrease in electron cloud density in its conjugate structure, increasing the adsorption of the positive charged methylene blue, ultimately resulting in a degradation efficiency of MAg- C₃N₄ being 1.5 times that of DCDA- g-C₃N₄.

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NEPE propellant has high energy and good mechanical properties. However, due to the lack of detailed research on its microscopic pyrolysis mechanism, the combustion rate and energy release rate are still difficult to control, which limits the further development of NEPE propellant. Based on this, quantum chemistry is used to study the pyrolysis mechanism of key components of NEPE propellant, including oxidants HMX and AP, binders PEG, NG and BTTN. The pyrolysis reaction path, rate-determining steps and main pyrolysis products of each component were calculated, and the pyrolysis kinetic parameters are calculated based on the transition state theory. The results show that HMX, BTTN and NG are all transformed into cyclic nitrogen compounds or chain carbon oxides by NO₂ or NO₃ shedding, and then gradually decomposed, while PEG is the gradual pyrolysis of long chain molecules. The main pyrolysis products are nitrogen oxides and various small fuel molecules containing C/H/N. The order of reaction rate constants of NEPE components is NG＞ AP＞ HMX＞ BTTN＞ PEG at 1500-2000 K. Among them, PEG and BTTN reaction rate constants are sensitive to temperature, and the reaction rate will rise rapidly with the increase of temperature. This study will provide an important theoretical reference for the regulation of NEPE high-energy catalyst pyrolysis behavior.

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Compared with hydrazine propellant, energetic ammonium dinitramide (ADN)-based liquid monopropellant has the advantages of high specific impulse, nontoxic, pollution-free, and easy storage. Moreover, ADN-based space engine has been applied in orbit, indicating a good application prospect. However, due to the use of a catalyst and catalyst preheating, it is impossible to realize the long life time of a thruster and the cold start of an engine in emergency. In this study, a new resistive ignition method was used to ignite ADN-based liquid propellant without a catalyst, and the electric ignition characteristics of ADN-based liquid propellant in nitrous oxide environment were studied. The results show that the resistive ignition method could be used to ignite ADN-based liquid propellant in nitrous oxide environment. The increase in voltage affected the decrease of ignition delay time, but slightly affected the combustion duration. With the increase in ambient pressure, the ignition duration of droplet gradually decreased. Voltage and ambient pressure slightly affected the energy consumption in nitrous oxide environment. Moreover, because the ignition delay time was much longer than the combustion duration, the ignition energy accounted for a high proportion of the energy consumed in the entire reaction process.

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