Biomass-derived carbon quantum dot-regulated nickel catalyst for flexible hydrogen generation from multiple chemical hydrides

Abstract

Flexible hydrogen release from multiple chemical hydrides is highly desirable for portable and decentralized energy systems, yet most reported catalysts are optimized for only a single fuel. Here, we report a biomass-derived carbon quantum dot-regulated nickel catalyst (Ni@CQD-S) that enables efficient hydrogen generation from three chemical hydrides: sodium borohydride (NaBH4), potassium borohydride (KBH4), and ammonia borane (NH3BH3). The catalyst was synthesized through a hydrothermal route using sucrose as a renewable carbon precursor, producing oxygen-functionalized carbon quantum dots that stabilize ultrasmall nickel nano-domains and create electronically coupled Ni-CQD interfaces. Structural analyses reveal that the CQD framework promotes high Ni dispersion, suppresses aggregation, and modulates the surface electronic state of Ni active sites. As a result, Ni@CQD-S exhibits broad catalytic activity under mild conditions (303 K), delivering maximum hydrogen generation rates of 2400, 1956, and 1536 mL min-1 g-1 for NaBH4, KBH4, and NH3BH3, respectively. The corresponding activation energies of 42.18, 40.65, and 43.34 kJ mol-1 indicate favorable and substrate-adaptive catalytic pathways. The catalyst also retains substantial activity over six consecutive cycles in all systems. Beyond rate performance, a Hydrogen Potential Catalytic Activity (HPCA) analysis identifies KBH4 as the most efficient hydride when hydrogen content and catalytic productivity are simultaneously considered. This work establishes biomass-derived CQD-metal interfaces as a scalable platform for multifunctional hydrogen generation and adaptive chemical hydride catalysis.