Enhanced Hydrogen Production from Methanol Photolysis on a Formate-Modified Rutile-TiO₂(110) Surface

We have investigated deuterium (D₂) formation from the photolysis of fully deuterated methanol (CD₃OD) on the clean and formate (DCOO^–) modified rutile (R)-TiO₂(110) surfaces at 266 nm using temperature-programmed desorption (TPD) and density functional theory (DFT) methods. Products, D₂O and D₂, have been detected on both surfaces during the TPD process. About 18.5% of the dissociated D atoms from CD₃OD photolysis contribute to D₂ formation on the DCOO^–-modified R-TiO₂(110) surfaces. The value is much higher than that on the clean R-TiO₂(110) surfaces, suggesting that surface DCOO^– can enhance D₂ production from CD₃OD photolysis on R-TiO₂(110). Further DFT calculation suggests that the BBO-CH-O-Ti_5c structure of HCOO^– on the surface can largely enhance the BBOv-mediated H₂ formation by lowering the barrier of recombinative H₂ desorption, leading to efficient H₂ production.