# A reflection on ‘A hydrazone-based covalent organic framework for photocatalytic hydrogen production’: teaching sponges new tricks

## TL;DR

This paper reflects on a pioneering study that introduced a hydrazone-based covalent organic framework for photocatalytic hydrogen production and discusses its impact and future directions.

## Contribution

The paper provides a critical reflection on a seminal COF photocatalyst and outlines advances and future opportunities in COF-based solar energy conversion.

## Key findings

- The hydrazone-linked COF demonstrated visible light-driven hydrogen production from water.
- The study inspired significant progress in COF photocatalysis over the past decade.
- Emerging challenges and opportunities in COF-based solar energy conversion are identified.

## Abstract

Covalent organic frameworks (COFs) are a unique class of porous materials built entirely from organic building blocks. As such, COFs unite the tunability of molecules with the robustness and optoelectronic functionality of extended solids—key requisites for (photo)catalysis. This LEGO®-like design of crystalline “molecular sponges” has captivated the imagination of chemists and inspired the first COF photocatalyst: a hydrazone-linked COF capable of harnessing visible light to drive the evolution of hydrogen from water. This commentary revisits that seminal contribution, published 11 years ago in Chemical Science (L. Stegbauer, K. Schwinghammer, B. V. Lotsch, Chem. Sci., 2014, 5, 2789–2793, https://doi.org/10.1039/C4SC00016A), and reflects on its lasting impact. We survey the major advances that have shaped COF photocatalysis over the past decade and outline emerging opportunities and challenges, offering a forward-looking perspective on the role of COFs in solar energy conversion.

In celebration of our 15th anniversary and some of our most popular articles, Bettina Lotsch reflects on the area of catalysis with covalent organic frameworks, building on a seminal paper published in Chemical Science on this topic (Chem. Sci., 2014, https://doi.org/10.1039/C4SC00016A).