Role of Nanointerfaces in Cu- and Cu+Au-Based Near-Ambient-Temperature CO Oxidation Catalysts

• Published in: ChemCatChem 2014-11, Vol.6 (11), p.3116-3124
• Main Authors: Gnanakumar, Edwin S., Naik, Jarpla Madhusudhan, Manikandan, Marimuthu, Raja, Thirumalaiswamy, Gopinath, Chinnakonda S.
• Format: Article
• Language: English
• Subjects: carbon monoxide; gold; heterogeneous catalysis; oxidation; redox
• ISSN: 1867-3880; 1867-3899
• DOI: 10.1002/cctc.201402581

Disordered mesoporous Cu‐doped ceria‐zirconia (Cu0.1Ce0.85Zr0.05O2), and gold deposited (Au/Cu0.1Ce0.85Zr0.05O2) catalysts were synthesized and evaluated for CO oxidation. Onset of CO oxidation activity, and 50 % (100 %) CO2 formation occurs at room temperature (RT), and 77 (120)°C, respectively, with Cu0.1Ce0.85Zr0.05O2. A small amount of gold on Cu0.1Ce0.85Zr0.05O2 induces the sustainable oxidation catalysis around RT. Onset of copper reduction temperature decreases from 110 °C on Cu0.1Ce0.85Zr0.05O2 to 48 °C with Au/Cu0.1Ce0.85Zr0.05O2, highlighting the direct interaction between Cu and Au through a Cu–Au interface. Au particles with a (0 0 1) facet deposit on an oxygen‐deficient site of (1 1 1) facet of CeO2‐ZrO2. Any decrease in surface Cu‐content with increasing Au‐content further supports the Au‐Cu‐Ce/Zr interface interactions. Nanointerfaces of Au clusters on Cu next to oxygen‐deficient sites of CeO2‐ZrO2 facilitate all the elementary steps of the CO+O2 reaction to occur in close proximity at ambient conditions. Don′t meddle with the surface: Ambient oxidation Cu‐Ov‐Ce and Au‐Cu‐Ov‐Ce nanointerfaces facilitate the tandem occurrence of elementary steps of CO oxidation in close proximity around ambient temperatures. The present non‐noble‐metal‐based catalysts for CO oxidation at ambient conditions adds to the growing list of such catalysts.