Optimization of catalyst for electrolysis and sono-electrolysis process for hydrogen production

This study explores hydrogen production and energy efficiency optimization in electrolysis and sono-electrocatalysis using ZnO, Cu 2 O, and graphene catalysts, where an ultrasonic bath, operating at 110W and a constant frequency of 40 kHz, was used as the ultrasound source. For electrolysis and sonoelectrolysis, a total of 26 experimental runs were conducted, including 13 runs for electrolysis and 13 for sonoelectrocatalysis, each lasting 5 min. The research indicates that sono-electrolysis can boost hydrogen production by 10–20 %. However, energy efficiency must be monitored due to the increased current and ultrasonic energy requirements. The study also evaluates the impact of different catalysts and their concentrations on maximizing hydrogen production and energy efficiency. Employing the Design of Experiments (DOE) approach, Response Surface Methodology (RSM), and Analysis of Variance (ANOVA), the study optimized both the sono-electrocatalysis and electrocatalysis processes. Optimal condition for electrocatalysis was found with a ZnO catalyst concentration of 2.668 g/L, achieving a hydrogen production rate of 57.6 cm 3 /h and an energy efficiency of 7.85 %. The predictions made by the model closely aligned with the experimental results, confirming the model's accuracy. In sono-electrocatalysis, the use of 0.1 g/L of graphene led to a hydrogen production rate of 66.4 cm 3 /h and an energy efficiency of 2.43 %, with minimal experimental errors observed. These findings highlight the potential of these optimized processes for practical applications in sustainable energy solutions. • Hydrogen produced via electrolysis and sonoelectrocatalysis using three catalysts. • Sonoelectrocatalysis boosted H 2 yield by up to 20 %, with graphene as the best catalyst. • ZnO showed optimal electrocatalytic output at 57.6 cm 3 /h and 7.85 % efficiency. • Ultrasound improved H 2 production but increased energy consumption. • Results support future work on hydrogen purity and catalyst stability for scaling.