A mini review for hydrogen production routes toward carbon neutrality

Hydrogen energy is essential to establishing a sustainable and reliable energy system. The continuously growing demand for hydrogen is driven by the challenges associated with greenhouse gas emissions and resource depletion. This paper investigates and summarizes some intriguing hydrogen production processes that have evolved from laboratory stages to mature commercial applications. The analysis of techno-economic, environmental effects and investment trends of these processes are included. Currently, hydrogen is dominantly produced by methods with fossil fuels as feed. These technology processes are relatively mature and account for the majority of the world's hydrogen production, around 99%. However, these results in significant carbon emissions. Around 1400 million tons of carbon dioxide are emitted into the atmosphere. To achieve carbon neutral strategy, the hydrogen production from hydrocarbon fuels needs to become clean. Equipping carbon capture, utilization, and storage system is a promising way to reduce carbon emissions. In addition, hydrogen production schemes with zero carbon emissions like electrolytic and photocatalysis are attracting increasing attention. The survey results suggest that the price of hydrogen production associated with the addition of carbon capture equipment ranges from 1.47 to 6.04 USD/kg, which is higher than the value for the price without the additional facility (1.03–2.08 USD/kg). The introduction of carbon tax is expected to narrow the cost gap between the two. Besides, the cost of electrolysis remains expensive (6.25–12.2 USD/kg), depending on the energy source and electrolytic cell equipment. The high-pressure autothermal reforming technique coupled with carbon capture and electrolytic technique powered by renewable energy are favored by global commercial investment. Finally, key challenges and opportunities for clean hydrogen production are discussed in this paper. More attention should be paid to catalyst blockage or deactivation and the cost of carbon capture equipment for fossil fuel hydrogen production. For the new zero-carbon hydrogen production method, designing efficient, economical catalysts and electrolysis materials is essential for its large-scale application.