Improvement of Visible-Light H-2 Evolution Activity of Pb2Ti2O5.4F1.2 Photocatalyst by Coloading of Rh and Pd Cocatalysts

Pb2Ti2O5.4F1.2 modified with various metal cocatalysts was studied as a photocatalyst for visible-light H-2 evolution. Although unmodified Pb2Ti2O5.4F1.2 showed negligible activity, modification of its surface with Rh led to the best observed promotional effect among the Pb2Ti2O5.4F1.2 samples modified with a single metal cocatalyst. The H-2 evolution activity was further enhanced by coloading with Pd; the Rh-Pd/Pb2Ti2O5.4F1.2 photocatalyst showed 3.2 times greater activity than the previously reported Pt/Pb2Ti2O5.4F1.2. X-ray absorption fine-structure spectroscopy, photoelectrochemical, and transient absorption spectroscopy measurements indicated that the coloaded Rh and Pd species, which were partially alloyed on the Pb2Ti2O5.4F1.2 surface, improved the electron-capturing ability, thereby explaining the high activity of the coloaded Rh-Pd/Pb2Ti2O5.4F1.2 catalyst toward H-2 evolution.