# Engineering Iridium–Ruthenium Dual‐Atomic Active Sites on Redox‐Active Covalent Organic Frameworks for Boosted Overall Water Splitting

## TL;DR

This paper introduces a new electrocatalyst with dual-atom sites that improves water splitting efficiency in alkaline conditions.

## Contribution

A pyrolysis-free electrocatalyst with IrRu dual-atomic sites on redox-active COFs is developed for enhanced water splitting.

## Key findings

- IrRu DAS/AT-COF shows robust bifunctional activity and stability for HER and OER in 1 M KOH.
- The MASE effect enhances catalytic performance by balancing and accelerating key reaction steps.
- Operando spectroscopy and DFT calculations reveal the active site separation mechanism.

## Abstract

The achievement of conductive bifunctional covalent organic frameworks (COFs) for overall water splitting remains challenging due to the lack of multifunctional active sites. Herein, the atomically dispersed electroactive iridium‐ruthenium dual‐active sites are anchored on donor‐acceptor‐based redox‐active COF (Ace and TAPT, IrRu DAS/AT‐COF) as a pyrolysis‐free electrocatalyst for alkaline water electrolysis application. The as‐synthesized IrRu DAS/AT‐COF exhibits robust bifunctional activities and stability for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 m KOH, surpassing the benchmarks and most recent noble‐metal‐based catalysts. Operando spectroscopy and theoretical calculations unveil the multiple active sites separation mechanism on IrRu DAS/AT‐COF, where the giant multifunctional active‐site synergistic enhancement (MASE) effect was triggered by the intramolecular compensating electronic modulations between the IrSA and RuSA sites. This setting can balance the competitive effects of the following elementary steps and simultaneously accelerate them into the local environment of catalytic units, including (i) the improved conductivity and H2O adsorption, (ii) decreased H2O dissociation energy barrier, (iii) optimal adsorption of H/O intermediates. This work provides new insights into the design of multi‐site catalytic local environments in bifunctional COFs electrocatalysts for water electrolysis.

Atomically dispersed IrRu dual‐atomic sites are anchored on donor‐acceptor‐based redox‐active COF for overall water electrolysis, and the active sites separation mechanism induced by giant multifunctional active‐site synergistic enhancement (MASE) effect was explored by the operando spectroscopy and DFT calculations.