Co/Zeolite Catalysts Derived from Waste Fly Ash for Efficient Hydrogen Production by Methanolysis of NaBH4

Developing new ways to convert waste into value-added products is essential to reduce pollution and ensure sustainability. The use of industrial waste fly ash as a catalyst support was investigated in this study. Zeolite A and Zeolite X, which were synthesized from waste fly ash (FA) using a hydrothermal process, were also used as catalyst supports. A novel CoB/FA catalyst was synthesized for H2 production from sodium borohydride (NaBH4) with three different catalyst supports (Zeolite A, Zeolite X, and waste FA). FA-based Co catalysts were prepared by wet impregnation and chemical reduction and used to accelerate the methanolysis reaction for hydrogen generation from NaBH4. It was observed that the methanolysis reaction is effectively accelerated using CoB/FA, CoB/ZXF, and CoB/ZAF catalysts. The hydrogen generation rates (HGR) of catalytic methanolysis of NaBH4 with the synthesized catalyst were 8683.1, 11867.7, and 13616.1 mL·min-1·gCo-1 for CoB/FA, CoB/ZXF, and CoB/ZAF, respectively, at 25°C. Scanning electron microscopy (SEM) and X-Ray diffraction (XRD) were used to determine the morphological properties and surface content of the catalysts. Under ideal conditions, the activation energy of the reaction was determined to be 39.45 kJ mol-1 in the presence of the CoB/ZAF catalyst, which also exhibits remarkable cycling performance for the methanolysis of NaBH4. In addition, a high reusable stability of the hydrolysis reactions was observed with the CoB/ZAF catalyst after the fifth cycle. The evaluation of zeolites synthesized from waste FA as support materials for methanolysis reactions of NaBH4 is promising.