Spectrum of innovation: Analysis of twelve hydrogen production pathways in the age of artificial intelligence

This review examines the entire range of hydrogen generation technologies focused on four main aspects, recent advances, underlying reaction mechanisms, novel catalysts, and the role of artificial intelligence in the hydrogen production process. The survey features twelve separate production paths categorized by a color-coding system, where each color represents a specific combination of feedstock, energy input, and environmental impact for example, green (renewables). It presents a timely and comprehensive examination of conventional procedures (gray, black, and brown hydrogen), novel approaches (blue, turquoise, and green hydrogen), nuclear-derived processes (pink, red, and purple hydrogen), and cutting-edge technologies (white, yellow, and gold hydrogen). Each production process is assessed considering recent technological advancements, with particular emphasis on the incorporation of artificial intelligence, machine learning, and advanced materials science. The review explores detailed reaction processes and catalytic advancements for each manufacturing technique, emphasizing significant improvements in non-precious metal catalysts, smart materials, and hybrid systems. Key performance indicators such as efficiency (50–70 %), CO₂ emissions (near-zero to 20 kg CO₂/kg H₂), and production cost ($1–10/kg) are comparatively summarized to facilitate critical evaluation. Artificial intelligence contributions are critically discussed with a prime focus on catalyst discovery, process optimization, predictive maintenance, and smart system integration across different hydrogen routes. A special focus is placed on potential for cross-technology integration where the combination of diverse production methodologies and enabling technologies has resulted in innovative hybrid systems with improved performance attributes. The environmental impact estimates indicate CO₂ emissions ranging from 18 to 20 kg CO₂ per kg of black and brown hydrogen. In contrast, green hydrogen pathways exhibit near-zero emissions. The review concludes by determining the critical challenges and future study methods. The review also highlights the significance of artificial intelligence in integrated multi-color hydrogen production systems in realizing large scale sustainable hydrogen production operations.