Two‐Dimensional‐on‐Three‐Dimensional Metal‐Organic Frameworks for Photocatalytic H2 Production

Abstract A MOF‐on‐MOF heterostructure is attractive in material science because of its potential combined effects in catalysis. However, precisely controlling the growth pattern at the metal–organic framework (MOF) nucleation stage to manipulate the metallic composition and structure dimensionality remain a challenge. Herein, we introduce a polyvinylpyrrolidone‐assist kinetic‐control strategy to achieve the “anti‐epitaxial growth” pattern of a foreign MOF nucleus on the (111) facets of UiO‐66‐NH 2 octahedron seeds, and construct diverse two‐dimensional‐on‐three‐dimensional (2D‐on‐3D) MOF heterostructures (2D‐on‐3D Cu, Zn, Cd, Co, and Ni). Notably, the 2D‐on‐3D Cu exhibits a unique “dimensionality‐hybrid” effect in photocatalysis which led to a significant photoactivity enhancement over those of the traditional “dimensionality‐identical” 2D, 3D and 3D‐on‐3D MOF structures.