Three amine derivative/graphene oxide van der Waals heterostructures for the photocatalytic detoxification of As(III)

Abstract

Although van der Waals heterostructures (vdWHs) have suggested the considerable advantages in engineering photoelectronic properties, it remains the limited understanding for the roles of typical nitrogen configurations in vdWHs. Herein, pyrrolic N, pyridinic N, and graphitic N, are introduced into the vdWHs via assembling indole, quinoline, and indolizine with graphene oxide (GO). Pyrrolic N prefers to adhere to the hydroxyls on GO surface, pyridinic N is apt to be immobilized by the carboxyls, and graphitic N shows poor affinitive selectivity. Both pyrrolic and pyridinic N introduce new π→π* orbitals into the resulted vdWHs, while, graphitic N leads to an obvious decay of n→π* transition. All amine derivatives in the vdWHs inject electrons into the conduction band of GO to provide n-type doping, which leads to decreased bandgaps. The decreasing conductivities are observed in all vdWHs, which is temporarily ascribed to the unfavorable electronic correlations at the van der Waals interfaces. By contrast, pyrrolic N contributes more electrons to GO, which enables In-GO to exhibit stronger photocurrent response (almost 7 times as much as the other heterostructures and GO) and higher photocatalytic activity for oxidating As(III) (6.8, 3.6, and 2.0 times than Qu-GO, GO and Iz-GO, respectively).