Comparative hydrogen storage performance assessment of organic waste materials for sustainable energy applications

This paper investigates the electrochemical hydrogen storage performance of activated carbons derived from tea waste (TW), coffee ground (CG), maple leaves (ML), and pinecone (PC). The samples undergo magnetic activation with FeSO 4 .7H 2 O followed by carbonization. Their performance is evaluated using linear sweep voltammetry (LSV), cyclic voltammetry (CV), and galvanostatic charge-discharge (GCD). LSV shows that all samples promote hydrogen evolution with increasing current density in the negative potential region. CV demonstrates that pinecone and tea-derived carbons exhibit higher reversibility and capacitive behavior. GCD results indicate that commercial activated carbon delivers 5.79 μAh/g (0.0214 wt.%), while pinecone and tea carbons reach 3.89 μAh/g (0.0144 wt.%) and 3.25 μAh/g (0.012 wt.%). At 0 °C and 4 kPa, pinecone carbon records 0.389 wt.% compared to 0.0214 wt.% for CAC. SEM and EDS confirm that porosity and Fe dispersion support this performance. The study concludes that waste-derived carbon represents sustainable, low-cost hydrogen storage materials. • Magnetically activated carbons were derived from four organic waste materials. • Electrochemical tests showed promising hydrogen storage capacities at room temp. • Pinecone and tea waste carbons showed superior stability and reversibility in CV. • SEM-EDS results revealed porous morphology correlating with electrochemical output. • Study promotes eco-friendly, low-cost biochar use for hydrogen energy storage.