Catalytic Oxidation Mechanisms in Metal-Oxide and Copper-Based Systems

The catalytic oxidation of small molecules such as carbon monoxide, volatile organic compounds and hydrocarbons plays a central role in environmental remediation and industrial synthesis. Metal-oxide catalysts, especially those based on ceria, titania and spinel oxides, mediate redox conversions through lattice or surface oxygen, often invoking the Mars–van Krevelen mechanism. Copper-containing systems, from unsupported CuO to atomically dispersed Cu(I)/(II) sites, exhibit versatile activity in low-temperature oxidation owing to their redox flexibility and ability to form electrophilic oxygen intermediates. Advances in operando spectroscopy and theoretical modelling have elucidated the interfacial chemistry governing oxygen activation, transport and spillover, as well as the function of oxygen vacancies and asymmetric redox centres. Rational design of catalysts now integrates dopants, tailored morphologies and single-atom architectures to optimise active site dispersion, oxygen mobility and turnover frequency, thereby enhancing conversion efficiency under mild conditions. These developments promise improved emission controls in automotive exhaust and more efficient processes for sustainable chemical production.

Research from Nature Portfolio

Recent studies have shown that Sn-doping in Pt/TiO₂ catalysts activates reverse oxygen spillover at temperatures below 100 °C, greatly improving CO oxidation rates compared with conventional oxide-supported platinum. In situ spectroscopies reveal that CO adsorption at Pt²⁺ sites triggers Ti–O–Sn bond cleavage, generating Pt⁴⁺ species and facilitating oxygen transfer from the titania lattice to the metal. In a complementary advance, isolated Cu(I) sites anchored on ceria frameworks form a rare η²-O₂ electrophilic intermediate at ambient temperature. Operando X-ray absorption and electron paramagnetic resonance demonstrate that adjacent Ce³⁺ cations assist in the stepwise reduction of O₂ to two lattice O²⁻ species, creating bridged Cu–O–Ce sites with turnover frequencies an order of magnitude higher than those of CuO clusters.

Catalytic Oxidation Mechanisms in Metal-Oxide and Copper-Based Systems publication trend

The graph below shows the total number of articles in catalytic oxidation mechanisms in metal-oxide and copper-based systems across all publications each year (not limited to Nature Index journals).

Technical terms

Mars–van Krevelen mechanism: A redox pathway in which reactant molecules oxidise by consuming lattice oxygen, with the oxide subsequently reoxidised by gas-phase O₂.

Oxygen vacancy: A missing oxygen atom in a metal-oxide lattice that creates an active site for oxygen adsorption and redox reactions.

Reverse oxygen spillover: The migration of lattice oxygen from the support oxide onto the metal surface, enhancing oxidation activity.

η²-O₂ species: A diatomic oxygen intermediate coordinated to a metal site via both oxygen atoms, facilitating selective oxygen activation.

References

1. Reverse oxygen spillover triggered by CO adsorption on Sn-doped Pt/TiO2 for low-temperature CO oxidation. Nature Communications (2023).
2. Adsorption and activation of molecular oxygen over atomic copper(I/II) site on ceria. Nature Communications (2020).
3. Asymmetric Oxygen Vacancies: the Intrinsic Redox Active Sites in Metal Oxide Catalysts. Advanced Science (2019).
4. Transition-Metal Doped Ceria Microspheres with Nanoporous Structures for CO Oxidation. Scientific Reports (2016).
5. Design Aspects of Doped CeO2 for Low-Temperature Catalytic CO Oxidation: Transient Kinetics and DFT Approach. ACS Applied Materials & Interfaces (2021).