An innovative hybrid hydrogen generator using photoelectrochemical and electrolysis processes: Experimental study

• A novel hybrid PEC-conventional cell produces hydrogen continuously. • Cu 2 O Coating the photocathode improves catalysis and hydrogen generation. • The photocurrent production was determined to be 1.1 mA/cm 2 . • The energy and exergy efficiencies attained were 3.27% and 3.44%, respectively. Hydrogen is widely recognized as a clean and sustainable energy carrier in response to the growing demand for sustainable energy sources. Photoelectrochemical (PEC) water splitting offers a promising method for directly generating water from solar energy with minimal environmental impact. The present study introduces a newly designed hybrid version of PEC-conventional electrolysis system which uniquely manages the most beneficial features of both PEC and conventional electrolysis technologies, thereby offering an improved operational performance. The ability to continuously generate hydrogen, regardless of solar irradiation, is a significant benefit. The experimental examination of a hybrid hydrogen reactor for producing clean hydrogen is described. The experimental testing is conducted on two processes at three operating temperatures (25 °C, 40 °C, and 55 °C). Processes 1 and 2 are evaluated under two distinct illumination conditions: low (400 W/m 2 ) and high (800 W/m 2 ). The photocurrent production was determined to be 1.1 mA/cm 2 under 800 W/m 2 after conducting electrochemical experiments. The active electrode area of 49.2 cm 2 of the hybrid system demonstrated an exergy efficiency of 3.74 % and an energy efficiency of 3.58 % at an operating temperature of 55 °C, respectively. The Cu 2 O photocathode achieved 0.78 % solar-to-hydrogen (STH) efficiency at 800 W/m 2 and 55 °C, maintaining stability for 88 % of an hour.