Water Vapor Photoelectrolysis in a Solid-State Photoelectrochemical Cell with TiO₂ Nanotubes Loaded with CdS and CdSe Nanoparticles

In this study, polyol-made CdS and CdSe crystalline nanoparticles (NPs) are loaded by impregnation on TiO2 nanotube arrays (TNTAs) for solar-simulated light-driven photoelectrochemical (PEC) water vapor splitting. For the first time, we introduce a safe way to utilize toxic, yet efficient photocatalysts integration in solid-state PEC (SSPEC) cells. The enabling features of SSPEC cells surface protonic conduction mechanism use polymeric electrolytes, such as Nafion instead liquid ones, operation with gaseous reactants, like from ambient humidity. Herein, studied effects both operating conditions atmospheres modifications TNTAs-based photoanodes well-crystallized NPs. We showed 3.6 2.5 times increase photocurrent density defective TNTAs modified CdSe, respectively, compared pristine TNTAs. Electrochemical impedance spectroscopy structural characterizations attributed improved performance higher conductivity induced intrinsic defects well enhanced electron/hole separation at TiO2/CdS heterojunction under conditions. were evaluated cycling between high relative humidity (RH) (80%) low RH levels (40%), providing direct evidence effect and, turn, adsorbed water, cell performance. Online mass spectrometry indicated corresponding difference H2 production rate. addition, complete restoration was also achieved. presented system can be employed off-grid, depleted, air-polluted areas hydrogen renewable energy provides solution photocatalysts.