High catalytic activity of cobalt nanoparticles synthesized by ultrasonic spray method in sodium borohydride hydrolysis

Abstract

Enhancing the hydrolysis reaction of NaBH4 for efficient hydrogen production requires the development of effective catalysts. In this study, the solution particles used for nanoparticles synthesized using the ultrasonic spray (US) method were produced for the first time in N2 at room temperature in the gas and liquid intermediate phases. It also brings a new approach to synthesizing low-cost and efficient catalysts using ultrasonic spray technology. The proposed method involves US the CoCl2 solution into the NaBH4 solution to reduce cobalt, producing catalysts for hydrogenation. This innovative approach pioneers a gas-liquid interface reaction for metal reduction. The resulting catalysts were characterized using SEM, XRD, XPS, TEM, BET and FT-IR analysis. The influence of NaOH/NaBH4 concentration, solution temperature, and catalyst amount on hydrogen production rate was investigated, and kinetic parameters were analyzed to understand the reaction kinetics better. The hydrogen production rates of US-Co and reduction method (RM) Co catalysts under the same conditions were calculated as 3995 mlH2/min.gcat and 1245 mlH2/min.gcat, respectively. The activation energy values calculated for the NaBH4 hydrolysis of the US-Co catalyst using the nth-order and Langmuir-Hinshelwood kinetic models are 46.75 kJ/mol and 46.87 kJ/mol, respectively. Therefore, it can be concluded that the LangmuirHinshelwood kinetic model is consistent with the nth-order kinetic model. Experimental results showed that the ultrasonic spray method is very effective in producing active metal catalysts, offering promising opportunities for catalytic advances.