Synthesis and characterization of cobalt boride catalysts supported on al-cr pillared bentonite for hydrogen generation from the hydrolysis of sodium borohydride

In today's world, where fossil fuel sources are depleting, hydrogen plays a crucial role as it is a clean and environmentally friendly energy source. Chemical hydrides, such as sodium borohydride, which have a high storage capacity, are used as hydrogen sources. Economically viable and effective catalysts are needed to produce hydrogen from sodium borohydride rapidly and efficiently. In this study, Al-Cr pillared sodium bentonite supported CoB catalysts were synthesized using impregnation and reduction methods at different Al and Cr ratios for hydrogen production from the hydrolysis of sodium borohydride. XRD, BET, SEM-EDS, ICP-MS, XPS, and FTIR analyses were performed to determine the characteristic and structural properties of the synthesized catalysts. Subsequently, their effectiveness in hydrogen generation from the hydrolysis of NaBH4 was investigated. In catalytic hydrolysis experiments with the synthesized catalysts, the effects of Cr content (by weight %), catalyst amount, NaOH concentration, NaBH4 concentration, and temperature on hydrogen generation rate were studied, and the reusability of the most effective catalyst was examined. Among the prepared catalysts, the one with 3% Cr content, labeled CoB@AlCr3/Na-bentonite, produced hydrogen at a rate of 2854 mL/min.gcat at 50°C with 10% NaOH and 5% NaBH4 concentrations. The reaction with this catalyst lasted approximately 4.7 minutes, and the activation energy was found to be 55.98 kJ/mol. When considering the percentage efficiencies of the catalytic tests over cycles, the efficiency started at 89.6% in the first cycle and remained around 86% from the second to the fifth cycle. In conclusion, when compared with catalysts reported in the literature, the CoB@AlCr3/Na-bentonite catalyst was identified as an effective and economical alternative for hydrogen production from NaBH4.