Anchoring metalloporphyrin nanobelts on MXene nanosheets for efficient photocatalytic CO 2 reduction

Abstract

Abstract Metalloporphyrins featuring structurally tunable aromatic macrocycles and versatile metal coordination sites are widely recognized as promising molecular catalysts for photocatalytic carbon dioxide reduction. However, their catalytic performances are constrained by rapid recombination of photogenerated charge carriers, insufficient charge transfer efficiency, and structural instability caused by molecular aggregation. Anchoring metalloporphyrins onto conductive substrates, in particular ultrathin two‐dimensional (2D) nanostructures, can effectively accelerate interfacial charge transport efficiency, thereby improving photocatalytic activity toward CO 2 reduction. In this work, a novel 2D/2D heterojunction was designed and synthesized, which can serve as a highly efficient molecular catalyst for visible‐light‐driven CO 2 reduction. The abundant Co centers and N‐sites in the assembled cobalt‐coordinated porphyrin nanobelts can greatly enhance the adsorption and conversion of CO 2 . Meanwhile, the presence of few‐layer Ti 3 C 2 MXene nanosheets enables the accelerated interfacial charge transport from photoexcited metalloporphyrin to Ti 3 C 2 MXene. Rapid electron transfer is verified by Kelvin probe force microscopy (KPFM), in situ attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR), and irradiated X‐ray photonelectron spectroscopy (XPS). As expected, compared to pristine porphyrin, the metalloporphyrin/Ti 3 C 2 MXene heterojunction shows a 12.5‐fold increase in the photocatalytic activity for CO 2 reduction to CO.