Green Synthesis of Co-based Nanoparticles from Bean Shell Extract and Determination of the Effect of Their Activity on Sodium Borohydride Hydrolysis

The study investigated the effect of Co(0) and Co-B NPs catalysts synthesized using the method of green synthesis on the NaBH 4 hydrolysis process. The investigation of the structure and surface morphology of the catalysts was evaluated using XRD, SEM-EDX, TEM, FTIR, and XPS analyses. The effect of catalysts on NaBH 4 was examined at different catalyst amounts, different NaBH 4 /NaOH concentrations, and different temperature values. At 30 °C solution temperature, the highest HGR and TOF values for Co(0) NPs catalyst were determined as 7326 mL.min -1 .g -1 cat and 8572 mL.min -1 .g -1 cat , respectively. Under the same conditions, HGR and TOF values for Co-B NPs catalyst were determined as 12524 mL.min -1 .g -1 cat and 15189 mL.min -1 .g -1 cat , respectively. The calculated activation energies for Co(0) and Co-B NPs catalysts are 37.68 kJmol -1 and 21.28 kJmol -1 , respectively. Enthalpy and entropy values were calculated as 4.43 kJmol -1 and 44 Jmol -1 K -1 for Co(0) and 23.16 kJmol -1 and 98 Jmol -1 K -1 for Co-B NPs, using Eyring's equation, respectively. The catalysts showed a small decrease in activity over five cycles, indicating that they have potential for reusability.