Phyto-mechanochemical synthesis of Ag@GO/CNT catalyst: Enhanced hydrogen production via continuous flow system

Abstract

Because of its high energy capacity and lack of emissions, hydrogen is a promising alternative energy source. For sustainable development, hydrogen production from non-fossil sources is essential. Hydrolysis of sodium borohydride allows for rapid hydrogen production on demand, especially with a catalyst. Thus, developing efficient and cost-effective catalysts for this process is essential. Herein, a phyto-mechanochemical approach is utilized to obtain material containing silver (Ag), reduced graphene oxide (rGO), and multi-walled carbon nanotubes (CNT) to use as a high-performance H2 production catalyst at room temperature via the water displacement method. All the samples (Ag NPs, Ag@rGO, and Ag@rGO/CNT) were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The morphological analysis confirmed the presence of mechanochemical Ag NPs uniformly dispersed on rGO and CNT. The results revealed that Ag@rGO/CNT exhibited superior particle distribution and porosity characteristics, achieving a high hydrogen generation rate of 4243 mL/min.gcatThe activation energy for the sodium borohydride hydrolysis reaction on the Ag@rGO/CNT catalyst was 7.08 kJ/mol using the Arrhenius equation and the zero-order reaction calculation. The catalyst's superior performance is confirmed by its low activation energy compared to Ag NPs and Ag@rGO catalysts. The results of the recycling experiments also showed that, for four repetitive cycles, the catalyst's performance gradually declined after each cycle. The Ag@rGO/CNT catalyst's previously listed characteristics make it an effective catalyst for the hydrolysis of NaBH4 to produce hydrogen.