Contributed by: Zhiqiang Mao, Ismaila Dabo, Raymond Schaak
J. Am. Chem. Soc. (2023), 145, 6753−6761, https://doi.org/10.1021/jacs.2c12887
A high-entropy ceramic with five different cations (Fe0.2Co0.2Ni0.2Cu0.2Zn0.2)Al2O4 was fabricated by a MRSEC team using powder processing. These cations span a range of electronegativities and local structural distortions. The diversity in elemental electronegativity and orbital interactions enables the material’s bandgap to be reduced below those of any of the parent phases, affording the possibility to maximize solar absorption and electrocatalytic performance.
This new high-entropy ceramic discovered by the MRSEC team can promote electrochemical water splitting at higher rate than state-of-the-art IrO2 electrocatalysts at comparable overpotential and potentially lower production cost.
What Has Been Achieved: A new family of ceramics that offer strong catalytic activity, even stronger than some benchmark high performance materials like IrO2. This is important because many of the good catalysts are based on expensive and rare noble metals. Everything in the present composition is abundant and inexpensive.
Importance of the Achievement: High performance and abundant catalysts are an important component of clean energy technologies.
How is the achievement related to the IRG, and how does it help it achieve its goals? This IRG endeavors to demonstrate that configurational entropy, through cation formulation (i.e., many cations in one crystal) can be exploited to engineer properties in new materials in new ways. This discovery makes a strong case via catalysis that the MRSEC’s entropy-value hypothesis is indeed correct. In simpler terms, this enhanced catalytic activity is possible because of the high-entropy host.