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

Abstract

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.