Photocatalytic hydrogen production from seawater under full solar spectrum without sacrificial reagents using TiO2 nanoparticles

Photocatalytic water splitting (PWS) has attracted widespread attention as a sustainable method for converting solar to green hydrogen energy. So far PWS research has mainly focused on the development of artificial photocatalytic hydrogen production systems for pure water. It is more practically attractive to create systems for seawater, i.e., to reduce the cost of hydrogen production and make better use of naturally occurring water resources. Herein, brookite, anatase, and rutile TiO2 nanoparticles are investigated as photocatalysts to explore the feasibility of such thought and have shown attractive hydrogen production performance under full solar spectrum without any sacrificial agent. It is worth noting that, brookite TiO2, has more suitable band gap position and excellent photoelectric properties compared with anatase and rutile TiO2, and has higher efficiency and stability in the process of hydrogen production. The photocatalytic hydrogen production rate of brookite TiO2 can reach up to 1,476 µmol/g/h, the highest value reported for TiO2-based systems and most other photocatalysts in seawater splitting under full spectrum. As the Cl− ions in seawater go through a cycle of oxidation and reduction, no Cl2 is detected in the solar hydrogen production from seawater.