Pd(II), Pt(II) metallosupramolecular complexes as Single-Site Co-Catalyst for photocatalytic H2 evolution

In artificial photocatalysis, sluggish kinetics of surface redox reactions and high charge recombination have been the barriers to photocatalytic conversion efficiency. Herein, metallosupramolecular complexes PYTA-Pd(II) and PYTA-Pt(II) were constructed by 1,2,3-triazopyridine derivatives (PYTA) coordinated Pt(II) and Pd(II). Originating from their planar conjugate structure and metal active center, PYTA-Pd(II) and PYTA-Pt(II) worked as molecular co-catalysts that can not only reduce the energy barrier of hydrogen evolution but also promote charge transfer. When g-C3N4 (CN) is loaded with PYTA-Pd(II) or PYTA-Pt(II), its photocatalytic H2 evolution reaction activity increased by 264 and 303 times, respectively. Moreover, the turnover frequency (TOF) of the Pd(II) in the CN/PYTA-Pd(II) is 25.94-fold than that of the Pd metal in the CN/Pd photocatalyst. And the TOF of Pt(II) in the CN/PYTA-Pt(II) photocatalyst is 9.37-fold than that of the Pt metal in the CN/Pt photocatalyst. These metallosupramolecular co-catalysts represent a new and highly effective approach to boost photocatalytic H2 evolution and have provided fertile new ground for creating high-efficiency photosynthesis systems, increasing the utilization efficiency of noble-metal.