Controllable interface engineering of g-C3N4/CuS nanocomposite photocatalysts

Abstract

The rational fabrication of an efficient photocatalyst with optimal interface engineering remains a huge challenge for the enhancement of photocatalytic perpformance. Herein, a sequence of multidimensional nanocomposites with different spatial interfaces, including point, and line or face-contact surface are controllable designed by horizontal growing diverse dimensional (0D, 1D,2D and 3D) copper sulfide (CuS) on 2D graphitic-carbon nitride (g-C 3 N 4 ) nanosheets. Physical and photochemical measurements demonstrate that the formation of an extraordinary 2D/2D face-to-face contact interface can not only enhance the specific surface area, visible light utilization, and photo-excited charge separation efficiency, but also elevate the density and lifetime of photo-generated carriers. The results of ultraviolet photoemission spectroscopy (UPS) and density functional theory (DFT) calculation also confirm that charge transfer tends to occur in face-to-face contact. Among the types of nanocomposites considered, 2D/2D g-C 3 N 4 /CuS has the smallest electron transfer barrier (Ф Be ) between active species, thereby displaying the maximum photocatalytic apparent rate constant, which is about 12 times larger than that of pristine g-C 3 N 4 . Most importantly, this work systematically investigates the relationship between microscopic interface structure and photocatalytic activity from the perspective of the optical, and electrical and energy levels, providing a new insight on the rational design of desired interface engineering towards efficient photocatalysts. • 2D/xD g-C3N4/CuS nanocomposites with different spatial interfaces were fabricated. • 2D/2D g-C3N4/CuS nanocomposite displays the optimal photocatalytic performance. • The concentration, lifetime and separation-efficiency of photogenerated carriers were tested. • The energy barrier between active species and catalysts was analyzed by UPS and DFT. • The photocatalytic mechanism of 2D/2D g-C3N4/CuS nanocomposites is proposed.