Synthesis of Copper/Sulfur Co-Doped TiO2-Carbon Nanofibers as Catalysts for H2 Production via NaBH4 Hydrolysis

Abstract

Copper/sulfur co-doped titanium dioxide-carbon nanofibers (Cu,S-codoped TiO2 NPs, decorated-CNFs) catalysts were synthesized using the electrospinning process to produce composite nanofibers (NFs). These composite NFs were utilized for the hydrolysis of sodium borohydride (SBH) to generate hydrogen gas (H2), taking advantage of their catalytic properties. The experimental results demonstrated that using 100 mg of composite NFs yielded the highest catalytic activity for H2 production, generating 79 mL of H2 gas within 6 min at 25 °C and 1000 revolutions per minute (rpm) using 1 mmol of SBH. As the catalyst dosage was reduced from 100 mg to 75, 50, and 25 mg, the reaction time increased by 9, 13, and 18 min, respectively. Kinetic studies revealed that the reaction rate followed a first-order reaction, indicating a direct proportionality between the rate of reaction and the catalyst amount. Additionally, it was observed that the concentration of SBH had no influence on the reaction rate, suggesting a zero-order reaction. Increasing the reaction temperature resulted in a reduced reaction time. The activation energy was determined to be 26.16 kJ mol−1. The composite NFs maintained their superior performance over five iterations. These findings suggest that composite nanofibers have the potential to serve as a cost-effective alternative to expensive catalysts in hydrogen production.