Solar-driven overall water splitting over a S-scheme semiconductor heterojunction of 2D g-C3N4/1D LaNbON2

g-C3N4 usually acts as the oxidation counterpart for overall water splitting reactions in semiconductor heterojunctions. Due to the poor water oxidation ability of g-C3N4, it is difficult to achieve efficient photocatalytic overall water splitting over g-C3N4-based heterojunctions. In this work, one-dimensional (1D) LaNbON2 with strong water oxidation ability is prepared for the first time, and combined with two-dimensional (2D) g-C3N4 to form semiconductor heterojunction by electrostatic self-assembly. The results of surface states, theoretical calculations, band structures and chemical probes indicate that the 2D g-C3N4 and the 1D LaNbON2 are tightly bonded through the electrostatic attraction and form a S-scheme type semiconductor heterojunction. In the heterojunction, the 1D LaNbON2 and the 2D g-C3N4 work as oxidation and reduction counterpart, respectively. The built-in electric field at their heterointerfaces effectively accelerates carrier separation. Thereby the solar-driven photocatalytic overall water splitting rate of the optimal 2D g-C3N4/1D LaNbON2 heterojunction is ∼ 3.3 times as much as that of the 2D g-C3N4.