Light-storing assisted photocatalytic composite g-C3N4/Sr2MgSi2O7:(Eu,Dy) with sustained activity

[Display omitted] •The light-storing assisted photocatalytic composite g-C3N4/Sr2MgSi2O7:(Eu,Dy) is prepared by one-step calcination.•g-C3N4/Sr2MgSi2O7:(Eu,Dy) has the ability to remove NO under illumination and dark.•For the first time, the concept of cumulative pollutant degradation concentration(SC) is defined which is used as an quantitative index to evaluate the photocatalytic performance under illumination and dark. The dependency of photocatalyst on light limits the large-scale application of photocatalysis technology. Thus, it was explored that the feasibility of the blue long afterglow phosphor and g-C3N4 for constructing a light-storing assisted photocatalytic composite with sustained activity in this study. The g-C3N4/Sr2MgSi2O7:(Eu,Dy) composite was prepared by a simple thermal polymerization method and the photocatalytic removal of NO under illumination and dark was studied. The experimental phenomena were explained from the aspects of optical properties, afterglow brightness and photoelectrochemical results. For the first time, the concept of cumulative pollutant degradation concentration(SC) was defined, which could be used as a quantitative index to evaluate the photocatalytic effect under illumination and dark. The results revealed that g-C3N4/Sr2MgSi2O7:(Eu,Dy) exhibited an enhanced photocatalytic activity under illumination due to the reduced recombination rate of carriers and the improved light absorption capacity. The existence of Sr2MgSi2O7:(Eu,Dy) as an internal light source endowed the composite with the ability to degrade pollutants continuously in the dark. The duration of photocatalysis in the dark was related to the brightness of afterglow and the photocatalytic activity. This study is helpful to promote the development of photocatalytic system with sustained activity.