Composites g-C₃N₄/Hydrochar/Black Mass Obtained from Spent Li-Ion Batteries for Enhanced Photoreforming of Organics to Obtain Hydrogen

This study presents a sustainable strategy for hydrogen production via photoreforming of organics [1], integrating circular economy principles through the valorisation of spent lithium-ion batteries (s-LIBs) and agro waste. Graphitic carbon nitride (g-C₃N₄) [2] was enriched with reduced black mass (BM-red) extracted from s LIBs [3] and hybridized with hydrochar (HC) derived from orange peel waste. The obtained HC underwent various activation treatments, namely, in acidic (Ha) or basic (Hb) conditions, as well as a physical activation (Hp) in order to improve its physico-chemical features and hence the photocatalytic performance. Composites containing g-C₃N₄ and black mass were synthesized by ball milling followed by a thermal treatment and then impregnated with the activated HC. Photoreforming experiments were carried out under UV or simulated solar irradiation, revealing the ability of some of the composites to obtain H2 in significative higher amount than the pristine g-C₃N₄. The influence of the organics (ethanol, glycerol, triethanolamine) which play the role of hole scavengers in the photocatalytic reaction carried out under nitrogen atmosphere was also assessedThe synergistic role of activated HC and the black mass as co-catalysts of the semiconductor g-C₃N₄ photocatalyst was confirmed. This work proposes a promising route for upcycling electronic and organic wastes into efficient photocatalysts for green hydrogen generation.