The synergistic effect of upconversion and built-in electric field in Tm3+ doped In-porphyrin (Zn) enhances light absorption and charge migration for highly efficient photocatalytic hydrogen evolution

Preparation of upconversion efficient In-TCPP(Zn) via an " internally-empowered " Strategy • Synergistic enhancement of light absorption and charge carrier migration via the upconversion effect and IEF • The IZT has highly efficient photocatalytic production capacity of H 2 . In recent years, most current studies on upconversion photocatalysts mainly focus on improving light harvesting, while their deeper role in regulating charge carrier dynamics remains insufficiently explored. Herein, high-photosensitivity Zn-porphyrin (ZnTCPP) was used as a ligand to synthesize In-TCPP(Zn) (IZT-X%, X represents the content of doped metal salts) doped with upconversion elements (Tm 3+ ). Among the series of synthesized materials, IZT-3% exhibited the most outstanding photocatalytic performance (1775 μmol·g −1 ·h −1 ), which is 8.07 times that of pristine In-TCPP(Zn). In-situ X-ray photoelectron spectroscopy ( in-situ XPS), time-resolved photoluminescence (TRPL), upconversion photoluminescence (UCPL) and DFT analyses reveal that the incorporation of Tm 3+ improves the charge distribution and enhances the built-in electric field (IEF) in In-TCPP(Zn), thereby accelerating charge carrier migration. Simultaneously, Tm 3+ can upconvert low-energy near-infrared (NIR) light to visible light that can be absorbed by In-TCPP(Zn), thereby significantly enhancing its photocatalytic performance. This study highlights the key role of upconversion doping in modulating charge carrier dynamics and provides new insights into the synergistic effect of upconversion and the IEF for improving photocatalytic hydrogen evolution efficiency, thereby broadening the utilization of near-infrared light. Download: Download high-res image (205KB) Download: Download full-size image