Abstract
This paper reviews modern approaches to developing manganese nanocatalysts as a promising alternative to expensive noble metals for photocatalytic hydrogen production. The main advantages and disadvantages of traditional hydrogen production methods from fossil fuels and green hydrogen from renewable energy sources are analyzed. The influence of morphology, nanostructure, specific surface area, crystal planes, and concentration of structural defects of manganese oxides and nanocomposite systems MnO₂-AC, CeO₂-MnO₂, and MnO₂-g-C₃N₄ on their catalytic efficiency and ability to mimic the natural water-oxidation complex of photosynthesis is investigated in detail.