Rapid hydrogen generation via NaBH4 methanolysis: The synergetic effect of Zn(OH)2/ZnO@sp2-C heterostructure tuned via biomass-derived carbon nanodots

Sodium borohydride (NaBH4) methanolysis is a promising approach for hydrogen production, however, requires costly noble-metal catalysts and a complicated synthesis route. This study introduces Zn(OH)2/ZnO@sp2-Cx (ZZ@sp2-Cx) nanocomposite as a new catalyst for rapid NaBH4 methanolysis. The catalyst is successfully synthesized via facile one-pot hydrothermal method using biomass-derived carbon nanodots (CNDs) and zinc chloride salt (ZnCl2) as a precursor. It is found that the ratio of CND to deionized water (1:3) is critical for supplying optimal sp2-C in tuning Zn(OH)2/ZnO ratio and excellent catalytic activity of ZZ@sp2-Cx nanocomposite. ZZ@sp2-C0.05 exhibited notably high catalytic hydrogen generation rate (HGR) of 81.89 L g- 1.min- 1 within 2.33 min, with low activation energy (Ea) of 14.5 kJ mol-1. Moreover, it maintained 94.6 % catalytic activity after seven consecutive cycles, comparable to noble metals, and outperformed state-of-the-art ZnO-based catalysts. Therefore, utilizing biomass-derived CNDs for tuning Zn(OH)2/ZnO heterostructure for efficient hydrogen generation via NaBH4 methanolysis is promising.