Theoretical and Experimental Study of Doping BaTiO ₃ with Cu and Fe to Boost Piezocatalytic Activity

This article explores the enhancement of piezocatalytic performance in barium titanate (BaTiO ₃ ) through doping with iron (Fe) and copper (Cu). Density functional theory calculations using the Spanish Initiative for Electronic Simulations with Thousands of Atoms method are conducted to evaluate formation energies for interstitial and substitutional doping. In the interstitial case, a single Fe or Cu atom is inserted into a BaTiO ₃ matrix of 135 molecules, while substitutional doping involved replacing barium (Ba) or titanium (Ti) atoms, yielding Ba ₀ . ₉₇ Fe ₀ . ₀₃ TiO ₃ , BaTi ₀ . ₉₇ Fe ₀ . ₀₃ O ₃ , and the corresponding Cu analogs. Results showed that substitution at the Ba site is energetically most favorable. Hydrothermal synthesis, followed by X‐ray diffraction field emission scanning electron microscopy and X‐ray photoelectron spectroscopy confirmed successful Fe and Cu incorporation predominantly at the Ba site. Piezocatalytic performance is assessed by Congo red dye degradation, where doped samples demonstrated superior activity compared to pure BaTiO ₃ with Cu doping showing the highest efficiency. Scavenger experiments confirmed that degradation is mainly driven by piezocatalysis. The enhanced activity is attributed to increased charge carrier density and improved catalytic sites, highlighting the promise of Fe‐ and Cu‐doped BaTiO ₃ for environmental remediation applications.