# Perspectives of Hydrogen Generation in Cavitation-Jet Hydrodynamic Reactor
## 1 Introduction  
The pursuit of affordable, renewable, and eco-friendly energy sources is motivated by growing concerns over the scarcity of fossil fuels and the effects of global warming. Hydrogen emerges as a viable alternative energy source with the potential to significantly influence specialized sectors, including fuel cells, combustion engines, and gas turbines [1; 2; 3]. Low-carbon hydrogen has the capacity to substitute natural gas in heating buildings, industrial operations, and backup power generation and can serve as a fuel or raw material for energy-demanding industries [4]. Energy and environmental safety are key advantages of hydrogen, along with its high efficiency. The significance of hydrogen in processing various types and in decarbonizing current production continues to grow. Future energy supply systems will likely feature multiple instances of generating both electricity and other energy forms from natural gas at the same location. This includes utilizing shared infrastructure for natural gas supply, connections to the electricity grid, transportation, and geological CO\({}_{2}\) storage in carbon capture, utilization, and storage (CCUS) industrial clusters. Comparing current industrial technologies for hydrogen production shows that the steam-methane reforming processis more efficient than water electrolysis and methane pyrolysis [5; 6]. Furthermore, the development of hydrogen distribution networks is anticipated, provided that sufficient quantities of hydrogen can be produced at competitive prices [7]. All current large-scale methods for producing organic chemical products from natural gas, primarily methane, rely on a two-stage process. Initially, natural gas is transformed into synthesis gas, a mix of carbon monoxide and hydrogen, at temperatures around 1000 \({}^{\circ}\)C [8; 9]. This process's complexity stems from its significant energy and capital demands, which constitute 70% of the overall costs of the final product. The subsequent stage is the generation of organic compounds from synthesis gas (via the Fischer-Tropsch process), necessitating high temperatures (300-350 \({}^{\circ}\)C) and pressures (2-3 MPa) with the use of Fe-Co catalysts [10; 11; 12; 13; 14]. The advancement of technology should aim to streamline and enhance the efficiency of converting natural gas into synthetic gas. This could be realized through various methods, including multi-channel reactor processes, catalyst-assisted methane oxidation at millisecond contact times, combustion-based filtration, matrix conversion of hydrocarbons, and plasmochemical techniques. Current technologies fall short of this purpose, necessitating the development of simpler, more cost-effective, and smaller-scale technologies. Such technologies would employ easily dismantled equipment and be transferable to a new location once the original site's resources are exhausted [15]. The application of plasma technology, particularly atmospheric-pressure non-thermal plasma, is increasingly favored for hydrogen production through methane activation. Non-thermal plasma produces a variety of highly reactive species, such as energetic electrons, radicals, and excited species, which facilitate chemical reactions. This allows for the elimination of expensive and impurity-prone catalysts while keeping energy costs low due to their relatively low gas temperature and high chemical selectivity [16]. Nonthermal plasma systems boast a high reaction rate, quick attainment of steady state, and high specific productivity, ensuring swift start-up and shutdown of the plasma process [17; 18]. Such systems can be flexibly integrated into small-scale hydrogen production systems. Moreover, the ability of nonthermal plasma systems to harness electricity from intermittent renewable sources like solar and wind offers a remedy for the mismatch between energy production and consumption from renewables [19; 20].