Development of multimetallic nanocatalyst and for hydrogen production from ammonia borane in liquid phase

In this study, activated carbon (AC) supported palladium, cobalt and silver nanoparticle (PdCoAg/AC) catalysts were prepared by in situ reduction of sodium borohydride (NaBH4) and characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX), Transmissionelectronmicroscopy (TEM) and X-ray PhotoelectronSpectroscopy (XPS). The PdCoAg/AC catalyst is active in the hydrolysis of ammonia-borane (AB) even at low temperatures. Compared with mono- (Pd) and bi-metallic (PdCo) nanoparticles, this trimetallic (PdCoAg) structure showed greatly increased catalytic activity for AB hydrolysis. In the experiment carried out at 25 ºC, 2 mmol AB and 50 mg PdCoAg / AC catalyst, the hydrogen production rate (HG) was determined to be 4666.66 mL min-1g-1. The activation parameters (Ea, ∆H and ∆S) in the catalytic hydrolysis of AB were obtained 26.84 kJmol-1, 29.42 kJmol-1 and -108.42 Jmol-1K-1, respectively. In addition, the study showed that Pd0.6Co0.2CAg0.2/AC (Pd:Co:Ag atomic ratio=6:2:2) showed the total turnover frequency (TOF) value of 6624 h-1. In this study, additionally the optimization of hydrogen (H2) production by AB over PdCoAg/AC was investigated using response surface methodology (RSM).