Spin-Polarized Total-Energy Calculations on Designing Magnetic Single-Atom Catalysts on the ZnO(0001) Surface with Pt and Pd

Magnetic single-atom catalysts (MSACs) are the key to developing efficient catalysts. Zinc oxide (ZnO) is a cheap and versatile platform for its construction. Several efforts have been put into studying doped ZnO with transition metals to module its band gap, to modify its optical properties, or to improve its magnetic and electronic properties for spintronic, optoelectronic, photocatalytic, and gas-sensing nanoscale devices. However, effort must be directed toward enhancing its excellent catalytic properties with transition-metal atoms. Here we demonstrated, by an atomic-scale analysis, that single-atom Pd- and Pt-ZnO generate spin-polarized catalysts. The main result is that, even when Pd and Pt are not magnetic, the O vacancies and surface effects induce magnetism in the incorporated atoms. The spin density and electrostatic potential evidenced a high reactivity generated mainly by the magnetic character. Our results show that MSACs have a high-spin selectivity towards O-2, improving the adsorption energy by about 33 times compared to when O-2 adsorbs on the O vacancy systems. The constructed system may be a highly efficient nanoscale device for MSACs, specifically for the oxygen reduction reaction (ORR), with high implications in energy and environmental remediation applications.