Stabilization of Cu<sub>2</sub>O through Site-Selective Formation of a Co<sub>1</sub>Cu Hybrid Single-Atom Catalyst
Chunlei Wang, Yuan Kong, Markus Soldemo, Zongfang Wu, Héloïse Tissot, Burcu Karagoz, Kess Marks, Joakim Halldin Stenlid, Andrey Shavorskiy, Esko Kokkonen, Sarp Kaya, Darı́o Stacchiola, Jonas Weissenrieder
Abstract
Single-atom catalysts\n(SACs) consist of a low coverage of isolated\nmetal atoms dispersed on a metal substrate, called single-atom alloys\n(SAAs), or alternatively single metal atoms coordinated to oxygen\natoms on an oxide support. We present the synthesis of a new type\nof Co<sub>1</sub>Cu SAC centers on a Cu<sub>2</sub>O(111) support\nby means of a site-selective atomic layer deposition technique. Isolated\nmetallic Co atoms selectively coordinate to the native oxygen vacancy\nsites (Cu sites) of the reconstructed Cu<sub>2</sub>O(111) surface,\nforming a Co<sub>1</sub>Cu SAA with no direct Co–O<sub><i>x</i></sub> bonds. The centers, here referred to as Co<sub>1</sub>Cu hybrid SACs, are found to stabilize the active Cu<sup>+</sup> sites\nof the low-cost Cu<sub>2</sub>O catalyst that otherwise is prone to\ndeactivation under reaction conditions. The stability of the Cu<sub>2</sub>O(111) surface was investigated by synchrotron radiation-based\nambient-pressure X-ray photoelectron spectroscopy under reducing CO\nenvironment. The structure and reduction reaction are modeled by density\nfunctional theory calculations, in good agreement with experimental\nresults.