Anchoring metalloporphyrin nanobelts on MXene nanosheets for efficient photocatalytic CO2 reduction
摘要
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 CO2 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 CO2 reduction. The abundant Co centers and N-sites in the assembled cobalt-coordinated porphyrin nanobelts can greatly enhance the adsorption and conversion of CO2. Meanwhile, the presence of few-layer Ti3C2 MXene nanosheets enables the accelerated interfacial charge transport from photoexcited metalloporphyrin to Ti3C2 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/Ti3C2 MXene heterojunction shows a 12.5-fold increase in the photocatalytic activity for CO2 reduction to CO.
Graphical abstract