Synthesis of Co-Cr(0) and Co-Cr-B catalysts from bean pods extract by the green synthesis method and their application in sodium borohydride hydrolysis

In this study, the effect of Co-Cr(0) and Co-Cr-B nanocatalysts on sodium borohydride hydrolysis was investigated. The extract obtained from the pods of the bean plant was produced using the environmentally friendly green synthesis method, along with the chemical reduction method as the production procedure for the catalysts. The analyses used to study the structure and surface morphology of catalysts are SEM, TEM, EDX, XRD, FTIR, and XPS. From the SEM and TEM pictures, the shape of the catalysts comprises of tiny spheres and has a porous nanostructure, and the particle size is 35–40 nm. The XRD investigation revealed that the catalysts had an amorphous structure. The catalysts’ structure has been confirmed to include the components Co, Cr, and B using EDX and XPS analyses. It was examined how different amounts of catalyst, different NaBH₄/NaOH concentrations, and different solution temperatures affected the hydrolysis of sodium borohydride. The n-th order kinetic model was utilized to determine the activation energies of Co-Cr(0) and Co-Cr-B nanocatalysts, which were found to be 24.39 kJ/mol and 43.09 kJ/mol, respectively. Also, the turnover frequency (TOF) values of synthesized nanocatalysts Co-Cr(0) and Co-Cr-B at 60 °C were calculated as 19,210 mLmin^{− 1}g^{− 1} and 12,410 mLmin^{− 1}g^{− 1}, respectively. The repeatability of catalysts in NaBH₄ hydrolysis showed high activity even after the fifth use.