Constructing HNT-AC Supported CoNi Nanoparticles for Hydrogen Generation toward NaBH₄ Hydrolysis: Optimization with RSM-CCD

In this study, activated carbon (AC) obtained from waste hazelnut shell and halloysite nanotube (HNT) were used to prepare HNT-AC support material by hydrothermal method. CoNi/HNT-AC catalyst was synthesized by reducing Co and Ni on HNT-AC by chemical reduction method. CoNi/HNT-AC has been characterized using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N₂ adsorption–desorption, elemental mapping, and transmission electron microscopy (TEM) methods. The optimum reaction conditions for hydrogen generation through NaBH₄ hydrolysis on CoNi/HNT-AC catalyst were determined using response surface methodology (RSM). The proposed quadratic model for NaBH₄ hydrolysis on CoNi/HNT-AC was found to be statistically significant with a correlation coefficient of 0.96. Under the optimum reaction conditions of 40.76 mg catalyst, 0.18 M NaBH₄, and 8.64 wt% NaOH, the hydrogen generation rate (HGR) and activation energy (E_a) were obtained as 1114.16 mL/gcat. min. and 24.15 kj/mol, respectively.