Abstract
There is a growing interest in producing solar fuels from CO2 or H2O.[1] In recent years, metal-organic frameworks (MOFs) have emerged as promising photocatalysts.[2] MIL-125(Ti)-NH2 with the formula Ti8O8(OH)4-(O2CC6H5-CO2-NH2)6 is considered as a benchmark MOF-based photocatalyst for CO2 reduction and H2O decomposition. Regardless of the important achievements made in this field, using sacrificial agents such as triethanolamine or methanol for these two processes hampers practical application of these systems. It has been recently reported the possibility of using MOFs as heterogeneous photocatalysts to promote gaseous CO2 methanation by H2 [3] or H2O decomposition into H2 and O2 without sacrificial agents [4].
In this presentation, we discuss the influence of the presence of metal and metal oxide nanoparticles (NPs) like Pt, RuOx, and CoOx as co-catalysts within the structure of MIL-125(Ti)-NH2 for the photocatalytic overall water splitting (OWS) or gaseous CO2 methanation processes.[4] The most active photocatalyst prepared for the OWS contained Pt and RuOx NPs supported in MIL-125(Ti)-NH2, achieving a maximum hydrogen production of 218 ¿mol×g-1 and 0.32 % apparent quantum efficiency at 400 nm. In the case of the photocatalytic CO2 methanation by H2, using RuOx NPs supported MIL-125(Ti)-NH2 reached 52% CO2 conversion and 18.5 mmol×g-1 CH4 production after 22 h. This material has also proven stable, even under continuous flow operation (> 50 h) and visible light irradiation.[5]
