Identifying the active photocatalytic H2-production sites on TiO2-supported Pt nanoparticles by the in-situ infrared spectrum of CO

Identifying the active catalytic centers on catalyst surface is significant for exploring the catalytic reaction mechanism and further guiding the synthesis of high-performance catalysts. However, it remains a challange in developing the site-specific technology for the identification of the active catalytic centers. Herein, in-situ infrared spectroscopy of adsorbed CO, photo-catalytic hydrogen evolution reaction (HER) test and theoretical simulation were used to distinguish and quantify the different surface sites and their H2-production catalytic activity on TiO2-supported Pt nanoparticles (PtNPs). Two different types of surface Pt sites, tip Pt (Pttip) and edge/terrace Ptedge/terrace, on TiO2-supported Pt nanoparticles (PtNPs) were identified. The photocatalytic H2-production activity of TiO2-supported PtNPs shows a linear functional relationship with the number of Pttip sites. However, the number of Ptedge/terrace sites produced little effect on the activity of TiO2-supported PtNPs. First-principle simulations confirmed that H2-evolution at the Pttip sites owns a lower energy barrier than that at Ptedge/terrace. This findings would be helpful for the fabrication of high-performance Pt catalysts.