High-entropy oxide photocatalysts for green ammonia synthesis from nitrogen fixation in water

Ammonia, a critical chemical fertilizer and a potential hydrogen carrier can be sustainably synthesized from atmospheric nitrogen and water under ambient conditions through photocatalysis. In this study, high-entropy oxides with d⁰ and mixed d⁰+d¹⁰ cationic configurations are introduced as a new group of catalysts for nitrogen fixation and photocatalytic ammonia production. The oxides exhibit impressive efficiency in ammonia production compared to binary oxides, while the efficiency is improved by using a mixed cationic configuration. It was shown that the incorporation of d¹⁰ elements, such as gallium and zinc, boosts the photocatalytic reactions by improving light absorbance, charge separation and charge lifetime. These findings demonstrate the potential of high-entropy oxides as next-generation photocatalysts for green ammonia synthesis, offering an effective alternative to conventional catalytic systems.