HYDROGEN STORAGE IN POROUS CARBON MATERIALS OBTAINED BASED ON KAZAKHSTAN COALS

The study is devoted to the investigation of hydrogen sorption properties of activated carbon adsorbents made of coals from the Kazakhstan deposits "Shubarkol" and "Shoptykol". To activate the samples, KOH treatment in a ratio of 1:0.5 was used, followed by thermal activation at a temperature of 900 °C. The specific surface area of ​​the samples was determined using the BET method, and their ability to absorb hydrogen at different temperature conditions was assessed. The study showed that the largest specific surface area (926.67 m²/g) and maximum hydrogen sorption capacity (1.48 wt.%) at a temperature of 77 K are demonstrated by the powdered adsorbent "Shoptykol;KOH" (ratio 1:0.5, treatment temperature 900 °C). Adsorption-desorption isotherms of these materials classify them as type I and type II, which indicates the mesoporous structure of extruded adsorbents and the more developed microporous texture of powder analogs. Temperature studies have revealed that lowering the temperature increases both the specific surface area and the adsorption capacity for hydrogen, reaching a peak of sorption at cryogenic temperatures. In this regard, powdered "Shoptykol:KOH" (1:0.5, 900°C) is recognized as the optimal material for storing hydrogen due to its high specific surface area, developed microporous structure and exceptional ability to absorb hydrogen.