Engineering approach to enhance photocatalytic water splitting for dynamic H2 production using La2O3/TiO2 nanocatalyst in a monolith photoreactor

Abstract

In this study, photocatalytic activity of La loaded TiO2 NPs was enhanced by engineering approach using monolithic honeycomb assisted photo-reactor system for dynamic hydrogen production. La/TiO2 NPs loaded over monolithic honeycomb support were characterized by XRD, XPS, FESEM, RAMAN, HRTEM, BET, UV–Vis and PL-spectroscopy. The photocatalytic activity of La/TiO2 NPs was enhanced by 1.8 folds higher than using pristine TiO2 in a slurry photoreactor system. This enactment was due to larger surface area, faster charge carrier separation and decreased surface recombination centers due to the presence of oxygen vacancies. Moreover, using monolithic honeycomb support loaded with La/TiO2, H2 generation rate of 165.5 ppm/h was obtained, 9.19 folds higher than using La/TiO2 in a slurry phase. Moreover, apparent quantum yield and space yield of monolith photoreactor was 1.4 and 4.5 folds higher than the slurry phase photoreactor, respectively. The superior efficiency of monolith photoreactor was due to adaptable arrangement of reactor which permits most utilization of illuminated surface area and processing volume with effective mass transport which is restricted in a slurry phase photoreactor. Also, stability comparison of slurry and monolith photoreactor for hydrogen production reveals, reusability of La/TiO2 loaded over monolithic support was 4.18% higher than the catalyst suspended in slurry phase photo-reactor. Therefore, enhanced efficiency of catalyst can be obtained using monolith photoreactor for photocatalytic H2 production compared to suspended slurry system and can be employed for other energy applications.