Abstract
Single-atom catalysts were widely used to treat atmospheric pollution and alleviate energy crises through photocatalysis.However,how to prevent the aggregation of single atoms during the preparation and cat-alytic processes remained a great challenge.Herein,a novel ultrathin two-dimensional porphyrin-based single-atom photocatalyst Ti-MOF(abbreviated as TMPd)obtained through a simple hydrothermal syn-thesis strategy was used for photocatalytic hydrogen evolution and NO removal,in which the single-atom Pd tightly anchored in the center of porphyrin to ensure single-atom Pd stable existence.Com-pared with most reported MOFs-based photocatalysts,the TMPd showed an excellent hydrogen evolution rate(1.32 mmol g-1 h-1)and the NO removal efficiency(62％)under visible light irradiation.Aberration-corrected high-angle annular dark-field scanning transmission electron microscope(HAADF-STEM)and synchrotron-radiation-based X-ray absorption fine-structure spectroscopy(XAFS)proved that pd in TMPd existed in an isolated state,and the atomic force microscope(AFM)proved the ultrathin morphology of TMPd.DFT calculations had demonstrated that single-atom Pd could serve as the active center and more effectively achieve electron transfer,indicating that single-atom Pd played a vital role in photocatalytic hydrogen evolution.In addition,a possible photocatalytic pathway of NO removal was proposed based on ESR and in-situ infrared spectra,in which the catalysts anchored with single-atom Pd could produce more active substances and more effectively oxidize NO to NO2-or NO3-.The results suggested that coordi-nating single-atom metal species as the active site in the center of porphyrin could be a feasible strategy to obtain various ultrathin porphyrin-based single-atom photocatalysts to acquire excellent photocatalytic performance further.
维普
万方数据