Engineering of Z-scheme 2D/3D architectures with Ni(OH)2 on 3D porous g-C3N4 for efficiently photocatalytic H2 evolution

The construction of Z-scheme system to achieve efficient photolysis of water to produce hydrogen is a promising approach in the field of photocatalysis. In this work, two dimensionally (2D) crystallized Ni(OH)(2) nanosheets are loaded upon the surfaces of three dimensionally macroporous g-C3N4 (3D g-C3N4) via the electrostatic method, synthesizing 2D/3D Ni(OH)(2)/g-C3N4 (Ni/DOMCN) Z-scheme system. The optimized photocatalysts exhibit apparent quantum efficiency (AQE) of 8.2% at 400 nm and an excellent H-2-production rate of (similar to)87.2 mu mol h(-1) under visible light (lambda > 400 nm), which is (similar to)76 times higher than unmodified 3D g-C3N4. The excellent cyclic performance of optimized photocatalyst can be attributed to the redox process between Ni2+/Ni-0/NiO during the photocatalytic reaction. The advantages of modified photocatalysts are attributed to the following aspects: (1) The Z-scheme system, accelerating the separation of photogenerated electron-hole pairs and leading to more efficient photocatalytic hydrogen production; (2) 2D/3D hollow structures, facilitating the diffusion of the solution and the light reflections; (3) tight contact, promoting the transfer and separation of photogenerated charge carrier; (4) larger surface area, providing more reactive sites. This work highlights the critical role of the Z-scheme system in solar photolysis and provides new insights into the development of 2D/3D photocatalysts.