Selective photocatalytic decomposition of formic acid over AuPd nanoparticle-decorated TiO₂ nanofibers toward high-yield hydrogen production

We present high-yield hydrogen production through selective photocatalytic decomposition of formic acid by using electrospun TiO₂ nanofibers decorated with AuPd bimetallic alloy nanoparticles under simulated sunlight irradiation. By using only 5mg of the AuPd/TiO₂ nanofibers containing the 0.75% Au and 0.25% Pd, we could achieve an optimal H₂ generation rate of 88.5μmolh^-1 with an apparent quantum yield at 365nm as 15.6%, which is higher than that of the Pd/TiO₂ and Au/TiO₂ nanofibers by a factor of 1.6 and 4.5, respectively. The enhanced photocatalytic decomposition of formic acid for H₂ generation could be attributed to the stronger electron-sink effect of AuPd alloy nanoparticles, the high selectivity of Pd for the dehydrogenation of formic acid, and the surface plasmon resonance effect of Au. More importantly, we demonstrate that the photocatalytic processes enable re-activation of the AuPd nanoparticles that were poisoned by CO during thermal decomposition of formic acid. As such, the presented AuPd/TiO₂ nanofibers are promising materials for re-generation of H₂ under mild conditions from liquid storage carrier of hydrogen.