Enhancement of high entropy oxide (La0.2Nd0.2Sm0.2Gd0.2Y0.2)2Zr2O7 mechanical and photocatalytic properties via Eu doping

High entropy oxides are novel materials with diverse compositions that have received significant interest for their mechanical and photocatalytic properties. In this study, we enhanced the mechanical and photocatalytic performance of solid state fabricated high entropy oxide (La 0.2 Nd 0.2 Sm 0.2 Gd 0.2 Y 0.2 ) 2 Zr 2 O 7 through Eu doping. Samples doped with different Eu ion concentrations demonstrated good thermal stability under high temperature without phase transformation after sintering at 1500 °C. We performed high pressure X -ray diffraction measurements and found that bulk modulus and critical pressure were improved by approximately 30 GPa and 5 GPa, respectively. This significant compression difference confirmed that Eu doping enhanced structural stability under high pressure. (La 0.2 Nd 0.2 Sm 0.2 Gd 0.2 Y 0.2 ) 1.98 Eu 0.02 Zr 2 O 7 demonstrated the best photocatalytic performance, with a kinetic constant about 1.5 times that of undoped samples. The appropriate doping concentration, smaller grain size and wider light absorption range contribute to the better photocatalytic performance irradiated under UV light. This work provides valuable insights for the design and improvement of high entropy oxide mechanical and photocatalytic performance. Graphical abstract