Photoinduced dry and bireforming of methane to fuels over la-modified tio2 in fixed-bed and monolith reactors

Abstract

A systematic investigation on the performance of fixed-bed and monolithic reactors for dynamic photoinduced CO2 reduction with CH4 via dry and bi-reforming of methane over La-modified TiO2 nanocatalyst under UV light is conducted. La/TiO2 is synthesized using a modified sol–gel method, and the monolithic-coated catalyst is synthesized using a dip-coating method. The performance of La/TiO2 is tested for different reforming systems in both types of photoreactors. The results reveal 5 wt% La/TiO2 effectively promotes CO2 and CH4 conversion to CO, H2, and C2H6, whereas catalyst performance is greatly enhanced in the presence of H2O in both types of reactors via bireforming of methane (BRM). Lower temperature is favorable for CO production, whereas H2 and C2H6 yields are enhanced at higher temperature. Notably, the monolith photoreactor is favorable for enhanced CO and H2 yields. More interestingly, quantum yield (QY) for H2 in BRM using monolith photoreactor is 1.402%—an increment of almost 4.99-fold than dry reforming of methane (DRM). This can be attributed to enhanced CO2 adsorption with hindered charge recombination by La, appropriate redox potentials, larger illuminated surface area, and higher photon flux. The prolonged La/TiO2 activity in a monolith photoreactor for enhanced CO and H2 production signifies its potential for CO2 conversion applications.