Highly active hydrogen production from hydrolysis of potassium borohydride by caffeine carbon quantum dot-supported cobalt catalyst in ethanol solvent by hydrothermal treatment

Abstract

Herein, the efficiency of the Co catalyst synthesized in caffeine-based carbon quantum dot-supported material using ethanol solvent was evaluated for H2 production from the hydrolysis of KBH4. The chemical compositions and morphology structures of these caffeine carbon dot-supported Co catalysts were carefully characterized by XRD, TEM, BET, EDS, FTIR, XPS, and ICP/OES analyses. XPS, FTIR and EDX analyses showed abundant oxygen atoms on the caffeine carbon dot-supported Co catalyst. It can be attributed to the prevention of aggregation of particles by reducing the average particle size with both caffeine and carbon quantum dots materials. The catalysts prepared in methanol and ethanol solvent by hydrothermal treatment compared to water have significant effects on H2 production from KBH4 hydrolysis. The H2 production rate obtained by Co@MOF-CQD (ethanol) at 30 °C was 17,081 ml min−1g−1. At the same time, the TOF value obtained with 4% KBH4 for the Co@MOF-CQD (ethanol) was found as 2765 h−1. The reusability of Co@CQD-MOF(ethanol) for the catalytic hydrolysis of KBH4 for H2 production was evaluated by six consecutive experiments.