Designing efficient organic photocatalysts requires integrating strong light harvesting, efficient charge separation, and rapid mass transport within a material. Natural leaves provide inspiration for this challenge through their hierarchical “stem-mesophyll” organization, where structural compartmentalization enables synergistic functionality. Covalent organic frameworks (COFs), featuring crystalline porous networks and tunable dimensionality, offer opportunities to integrate distinct functions through structural design. However, developing COF architectures that draw inspiration from hierarchical natural designs while integrating multiple photocatalytic functions within a single system remains challenging.

In a study published in Nature Synthesis (DOI: 10.1038/s44160-026-01077-6) on May 22, 2026, led by Prof. ZHAO Xin, researchers from the Shanghai Institute of Organic Chemistry (SIOC), Southeast University, Shanghai Synchrotron Radiation Facility, and Wuhan University, reported an in situ one-pot synthetic strategy that constructs both one-dimensional (1D) and three-dimensional (3D) COFs from the same binary monomers within a single reaction system, yielding a hierarchically integrated, leaf-inspired COF heterostructure (1D@3DCOF-2).

In this strategy, the chain-like 1DCOF-CN and the porous 3DCOF-CN grow simultaneously within a single co-assembly process, integrating spatially to form an S-Scheme heterojunction. A built-in electric field established at the interface that promotes directional charge separation and migration between the two components. The hydrophilic 1DCOF-CN, enriched with amino groups and imine bonds, efficiently anchors and disperses Pt nanoparticles that serve as catalytic sites for proton reduction, while the porous 3DCOF-CN provides interconnected channels that facilitate light absorption, mass transport, and hole consumption.

With Pt as a co-catalyst, 1D@3DCOF-2 achieved a hydrogen evolution rate of 45.7 mmol g^-1 h^-1 under visible-light irradiation, outperforming 3DCOF-CN (31.1 mmol g^-1 h^-1) alone, whereas 1DCOF-CN showed negligible photocatalytic activity. The photocatalytic hydrogen evolution rate of the heterostructure further reached 337.8 mmol g^-1 h^-1 in pure water at a low catalyst loading of 0.2 mg and maintained a hydrogen evolution rate of 50.8 mmol g^-1 h^-1 in seawater, highlighting its potential for practical solar-to-hydrogen conversion. Combined experimental and computational studies revealed that the spatial integration of the 1D and 3D components is essential for preserving the efficient interfacial charge separation.

This work establishes a versatile one-pot synthetic strategy for constructing seamlessly integrated hierarchical COF@COF heterostructures and provides new insight into how dimensional integration in organic frameworks can be harnessed to mimic the structural integration of natural leaves for high-performance photocatalysis.

Schematic diagram of 1DCOF-CN, 3DCOF-CN and the integrated leaf-inspired 1D@3DCOF-2 heterostructure assembled from the same monomers. Inspired by the hierarchical organization of leaves, the heterostructure integrates mass-transport and catalytic functions within an architecture. AA: Ascorbic acid, OX: Oxidation product. (Image by SIOC)

Abstract

Key words: ; ; ; photocatalytic hydrogen evolution.

Prof. Dr. Xin Zhao

Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences

Lingl Ling Road 345 Shanghai 200032 China

Tel: 0086-21-54925023

Email: xzhao@sioc.ac.cn