The effective separation of the electron and hole (e-h) pairs plays a key role in enhancing the photo catalytic performance of the semiconductors. The density of electrons participating in the reduction reaction also determines photocatalytic performance. We report here a rational design of a photocatalyst assembly composed of n-type semiconducting two-dimensional g-C3N4 nanosheets (2D-C3N4), carbon nanotubes (CNTs), and plasmonic Ag nanocubes, which exhibits enhanced density of electrons and controlled unidirectional change flow to promote the photocatalytic hydrogen evolution reaction. Plasmonic Ag nanocubes inject the hot-electrons into conduction band of 2D-C3N4 to increase the density of electrons while the CNTs act as a power pump of the electrons to steer electron flow from the conduction band of 2D-C3N4 to reactants. The photocatalytic performance of Agi2D-C3N4/CNTs assembly was dramatically enhanced for the H-2 evolution from water. The enhanced photocatalytic activity is due to the efficient unidirectional transfer of the electrons with high density and efficient separation of the e-h pairs. (C) 2016 Elsevier B.V. All rights reserved.