Entropy-stabilized oxides with d10 and s0p0 cations as heterostructured photocatalysts with high work function: Experiments and first-principles calculations

Elements from the right side of the periodic table, including cations with d¹⁰ and s⁰p⁰ configurations, have been shown to improve photocatalytic activity in various photocatalysts either as dopants or principal elements. This study introduces the first medium- and high-entropy oxide photocatalysts accommodating only d¹⁰ and s⁰p⁰ cations. The designated oxides, AlZnGaO₄ and AlZnGaSnBiO_7.5 (dual-phase heterostructure of AlZnGaO₄ and 1/2Sn₂Bi₂O₇), demonstrate good optical properties and promising photocatalytic activity for water conversion to hydrogen and CO₂ conversion to methane compared to entropy-stabilized cations containing only d⁰ or d⁰+d¹⁰ configurations. The good activity of these oxides was ascribed to their high work function, which was supported by experimental analysis and first-principles calculations. Moreover, AlZnGaSnBiO_7.5 exhibited enhanced activity compared to AlZnGaO₄ due to the creation of type II heterojunctions and resultant higher charge carrier separation and lifetime. This study introduces the significance of d¹⁰+s⁰p⁰ cationic configuration, high work function, and inherent heterojunctions on the design of advanced high-entropy photocatalysts with high photocatalytic activity.