e_g Occupancy as a Predictive Descriptor for Spinel Oxide Nanozymes

Abstract

Functional nanomaterials offer an attractive strategy to mimic the catalysis of natural enzymes, which are collectively called nanozymes. Although the development of nanozymes shows a trend of diversification of materials with enzyme-like activity, most nanozymes have been discovered via trial-and-error methods, largely due to the lack of predictive descriptors. To fill this gap, this work identified e g occupancy as an effective descriptor for spinel oxides with peroxidaselike activity and successfully predicted that the e g value of spinel oxide nanozymes with the highest activity is close to 0.6. The LiCo 2 O 4 with the highest activity, which is finally predicted, has achieved more than an order of magnitude improvement in activity. Density functional theory provides a rationale for the reaction path. This work contributes to the rational design of high performance nanozymes by using activity descriptors and provides a methodology to identify other descriptors for nanozymes.

Rational Design Strategies for Nanozymes

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“…In addition, they plotted volcano maps of the specific activity of nanozymes and the occupancy of the e g orbitals and successfully predicted the highest POD-like activity of the spinel oxide LiCo 2 O 4 (Figure 3F), which exhibited more than 1 order of magnitude increase in the catalytic activity compared to the highest POD-like activity of ZnCo 2 O 4 in the spinel ZnB 2 O 4 series. 43 The above studies have demonstrated the ability of e g to accurately predict the POD-like activity of spinels and chalcogenides. As a material electronic structure descriptor, e g has a high potential for the prediction of other types of materials.…”

Exploring Cu-Doped Co3O4 Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

“…In addition, studies have revealed that the catalytic activity of spinel oxides for the oxygen reduction reaction (ORR) strongly relies on the occupancy of the e g orbitals of the transition metal cations at the octahedral (O h ) sites. − The transition metal e g orbitals exhibit significant overlap with the O 2p orbitals of the oxygen-related adsorbates. By achieving a moderate e g ≈ 1.0 configuration at the O h sites, the ORR/OER activity can be optimized by balancing the binding strength of oxygen intermediates involved in various rate-determining steps. , This modification facilitates the adsorption of O 2 and the dissociation of OH – , leading to enhanced ORR activity.…”

Mineral-Enhanced Manganese Ferrite with Multiple Enzyme-Mimicking Activities for Visual Detection of Disease Markers

“…Among enzyme mimics, spinel oxides (AB 2 O 4 ) have a well-defined but tunable crystal structure with two sites, octahedral (Oh) and tetrahedral (Td) sites, and the distribution of cations in two sites determines its catalytic efficiency. − In general, the Oh sites play a primary role during the catalytic reaction because they are preferentially exposed on the near-surface, and a shorter distance between Oh–Oh sites accelerates the reaction kinetics. − Currently, most studies were primarily focused on modulating Oh metal ion species and valence states to enhance their catalytic efficiency. For example, modulating the Oh site cations could regulate the peroxidase-mimicking activity of ZnB 2 O 4 (B = Cr, Mn, Fe, and Co) . The highest catalytic activity was observed when the Co cations occupied the Oh site.…”

“…For example, modulating the Oh site cations could regulate the peroxidase-mimicking activity of ZnB 2 O 4 (B = Cr, Mn, Fe, and Co). 21 The highest catalytic activity was observed when the Co cations occupied the Oh site. Using ZnMn 2 O 4 as a model material, the effect of Mn valence at Oh sites on its multiple antioxidant activities was explored.…”