Optimized activation of coffee-ground carbons for hydrogen storage

This study evaluates and compares physical, chemical, and dual activation methods for preparing activated carbons from spent coffee grounds to optimize their porosity for hydrogen storage. Activation processes, including both one-step and two-step chemical and physical methods, were investigated, incorporating a novel dual activation process that combines chemical and physical activation. The findings indicate that the two-step chemical activation yields superior results, producing activated carbons with a high specific surface area of 1680 m 2 /g and a micropore volume of 0.616 cm 3 /g. These characteristics lead to impressive hydrogen uptake capacities of 2.65 wt% and 3.66 wt% at 77 K under pressures of 1 and 70 bar, respectively. The study highlights the potential of spent coffee grounds as a cost-effective precursor for producing high-performance activated carbons. • Spent coffee grounds to produce efficient and low-cost activated carbons. • Preparation of activated carbons with highly tunable porosity features. • Double activation of spent coffee grounds-based activated carbons. • Correlation between activation methods and porosity formation.