Hydrogen production from sodium borohydride by ZnCl2 treated defatted spent coffee ground catalyst

Abstract

In the current study, a novel Zinc (Zn) treated defatted spent coffee ground catalyst (DSCG) was developed and applied successfully for hydrogen production from sodium borohydride (NaBH4). In order to synthesise the Zn treated DSCG catalyst, different Zn metal concentrations (10–50%), impregnation temperatures (50–90 °C) and burning temperatures (400–1000 °C) were tested. It was found that 40 wt % ZnCl2, 75 °C impregnation temperature and 1000 °C burning temperature provide the superior catalyst performance. Once the optimal catalyst preparation conditions were determined, the effect of NaBH4 concentration (1–7.5% NaBH4), catalyst amount (0.05–0.2 g catalyst) and temperature (30 °C–60 °C) on alcoholises reaction of sodium borohydride was comprehensively examined. The maximum hydrogen production rates (HPRs) for the Zn treated DSCG (40 wt % Zn) catalyst at 30 °C and 60 °C were found to be 8510.1 and 12,364 mlmin−1gcat−1, respectively. A detailed characterization of the catalyst was performed through use of Brunauer-Emmett-Teller analyser (BET), Fourier Transform-Infrared Spectrometer (FTIR), Thermogravimetric Analyser (TG), Scanning Electron Microscope combined with Energy-dispersive X-ray spectroscopy (SEM-EDX) and X-ray photoelectron spectroscopy (XPS). The activation energy was determined to be 7.87 kJmol−1. Additionally, the reusability of Zn treated DSCG catalyst was examined five times under same operating conditions.