# V-doped KNbO3 perovskite for enhanced photocatalytic hydrogen production from first-principles calculations

## TL;DR

This paper explores how adding vanadium to a material called KNbO3 improves its ability to produce hydrogen using sunlight.

## Contribution

The study introduces vanadium doping in KNbO3 and demonstrates its effectiveness in enhancing visible-light-driven hydrogen production through first-principles calculations.

## Key findings

- V doping reduces the bandgap of KNbO3, improving visible-light absorption.
- Mulliken electronegativity confirms the material's suitability for water splitting.
- XRD analysis confirms structural stability after V doping.

## Abstract

Photocatalytic water splitting represents a promising route for sustainable hydrogen production using solar energy. In this study, Density Functional Theory (DFT) is applied to investigate the influence of vanadium (V) doping on the electronic and optical properties of cubic KNbO3 (KNO). Simulations on KNb1−xVxO3(KNVO), with x = 0.11, were performed using the CASTEP module under both GGA-PBE and mGGA-RSCAN functionals to reach better computational reliability. The mGGA-RSCAN functional exhibits better accuracy in reproducing the experimental bandgap values. 11.11% V substitution at the Nb site significantly reduces the bandgap from 1.82 eV to 1.53 eV (PBE) and from 2.30 eV to 1.86 eV (RSCAN), enhancing visible-light absorption. Optical and conductivity analyses reveal improved absorption and charge transport properties in V-doped systems. XRD analysis confirms the cubic structural stability. The valence and conduction band edge potentials obtained from Mulliken electronegativity satisfy the redox potential criteria for water splitting. These findings suggest V-doped KNbO3 as a viable photocatalyst for visible-light-driven hydrogen production.

Photocatalytic water splitting represents a promising route for sustainable hydrogen production using solar energy.