2D photosensitive porphyrin-based MOFs integrated with a Pd cocatalyst with fast charge transfer for efficient photocatalytic hydrogen evolution

Abstract

To improve the charge carrier transport efficiency via reducing the transmission distance, a series of 2D MOF nanosheets with several transition metal clusters as metal nodes are prepared by a simple hydrothermal method for photocatalytic hydrogen production, in which PdTCPP integrates a photosensitive porphyrin with cocatalysts so as to realize fast charge carrier transport. The experimental results show that Co–TCPP(Pd) has the most outstanding hydrogen evolution activity (4.40 mmol g⁻¹ h⁻¹), which could be the reason that the noble metal Pd anchored in the porphyrin center plays a significant role in the electron transfer process, that is, the photogenerated electrons generated by the multivalent Co-oxo cluster excited by illumination are transferred from its own LUMO energy level to the self-photosensitized porphyrin ring through –COO–, and then together transferred to the active site of the precious metal Pd in the porphyrin center to achieve effective hydrogen evolution. The results provide us a feasible strategy to integrate the individual photosensitive porphyrin center with the cocatalysts into sole metalloporphyrins so as to shorten the charge carrier transmission distance for ultimately further improving the photocatalytic performance.