Photochemical water splitting performance of fluorescein, rhodamine B, and chlorophyll-Cu supported on ZrO2 nanoparticles layer anode

• Enhance the efficiency of solar hydrogen cells by ZrO2 absorbed dye molecules.
• Fluorescein and rhodamine B convert blue light and green light into red light.
• Sodium copper chlorophyll generated photoelectron onto ZrO2.
• Photon down-conversion mechanism increases solar light absorbance.
• Highest efficiency of hydrogen generation was 0.058 ml/cm2-h.

In this study, we tried to enhance the efficiency of solar hydrogen cells by using fluorescein, rhodamine B, and a combination of fluorescein with rhodamine B to coat an anode made by ZrO2 absorbed sodium copper chlorophyll molecules. Fluorescein and rhodamine B are utilized to convert blue light and green light into red light, which is in turn absorbed by sodium copper chlorophyll, causing photoelectrons to be generated onto ZrO2. This photon down-conversion mechanism increases the spectrum of solar light absorbance. According to the photon down-conversion mechanism, the efficiency of solar hydrogen production can be enhanced by absorbing more photons with different wavelengths in the visible light regime. The highest efficiency of hydrogen generation under air mass 1.5 global (AM 1.5 G) illumination (solar simulator) was 0.058 ml/cm2-h when a ZrO2 nanoparticles layer was coated with sodium copper chlorophyll and rhodamine B.