# Single-Atom Ru in CoFe-LDH Drives Efficient Charge Separation on BiVO4 for Solar Water Splitting

## TL;DR

Single Ru atoms in a CoFe-LDH catalyst improve charge separation on BiVO4, boosting solar water splitting efficiency.

## Contribution

A new method using single Ru atoms in CoFe-LDH cocatalysts to enhance BiVO4's performance in solar water splitting.

## Key findings

- The Ru0.51-CoFe-LDH/BiVO4 photoanode has a 3.1 times higher photocurrent density than bare BiVO4.
- The system achieves 100% charge collection efficiency and a 2:1 hydrogen-to-oxygen production ratio.
- Single Ru atoms optimize interfacial energetics and electron rearrangement in the catalyst.

## Abstract

The single Ru atoms trigger the electron rearrangement of Ru0.51-CoFe-LDH to engineer active sites and optimize interfacial energetics.The negative shift of Ru0.51-CoFe-LDH band edge gives rise to more conspicuous band bending of the n-n junction formed with BiVO4.The Ru0.51-CoFe-LDH/BiVO4 photoanode film displays a 3.1 times higher photocurrent density than bare BiVO4 and commendable charge collection efficiency (100%).

The single Ru atoms trigger the electron rearrangement of Ru0.51-CoFe-LDH to engineer active sites and optimize interfacial energetics.

The negative shift of Ru0.51-CoFe-LDH band edge gives rise to more conspicuous band bending of the n-n junction formed with BiVO4.

The Ru0.51-CoFe-LDH/BiVO4 photoanode film displays a 3.1 times higher photocurrent density than bare BiVO4 and commendable charge collection efficiency (100%).

The online version contains supplementary material available at 10.1007/s40820-025-02062-y.

Bismuth vanadate (BiVO4) is regarded as a promising photoanode for photoelectrochemical (PEC) water splitting. Despite its advantage in band gap and visible-light response, the BiVO4 exhibits an unsatisfactory achieving water splitting due to severe charge recombination. Herein, we elucidate an innovative approach involving the incorporation of single Ru atom with a CoFe-LDH cocatalyst (Ru0.51-CoFe-LDH) and integrating it onto the BiVO4 semiconductor substrate. The resulting Ru0.51-CoFe-LDH/BiVO4 photoanode film demonstrates commendable charge injection efficiency (76%) and charge collection efficiency (100%). Interestingly, the yield of hydrogen and oxygen increases linearly at a stoichiometric ratio of about 2:1, reaching 158.6 and 67.4 μmol after 140 min of irradiation, respectively. According to experimental characterization and density functional theory calculation, this remarkable performance results from single Ru atoms triggering the electron rearrangement of Ru0.51-CoFe-LDH to engineer active sites and optimize interfacial energetics. Additionally, the negative shift of Ru0.51-CoFe-LDH band edge gives rise to more conspicuous band bending of the n–n junction formed with BiVO4, expediting the separation and transfer of photogenerated electron–hole pairs at the interface. This work furnishes a new preparation perspective for PEC water splitting systems to construct single atoms in the semiconductor substrate.

The online version contains supplementary material available at 10.1007/s40820-025-02062-y.