Single-Atom Catalysis Mechanisms for CO Oxidation

Single-atom catalysis has emerged as a frontier in heterogeneous catalysis, offering maximised atom efficiency and unique electronic properties that differ markedly from nanoparticulate or bulk counterparts. In CO oxidation, isolated metal or non‐metal centres dispersed on supports such as oxides, carbonaceous materials or two‐dimensional substrates facilitate O₂ activation and CO activation via distinct pathways. Two principal routes dominate: the Langmuir–Hinshelwood mechanism, in which both CO and O₂ adsorb before reaction, and the Eley–Rideal mechanism, in which a gas‐phase molecule reacts directly with an adsorbed partner. Atomically dispersed sites can modulate adsorption energies, lower activation barriers and resist sintering or poisoning. Charge transfer between the support, the single atom and reactants tunes reactivity, while the local coordination environment—vacancies, heteroatom dopants or defect sites—governs both stability and catalytic cycle. Recent advances have highlighted metal‐free single‐atom platforms and transition‐metal sites anchored on two‐dimensional materials, demonstrating CO oxidation at or near room temperature with high turnover frequencies.

Research from Nature Portfolio

Investigations of heteroatom‐doped graphene have shown that co‐ordination of phosphorus and nitrogen creates highly active single‐atom centres. A two‐coordinated P site adjacent to N atoms promotes O₂ dissociation and lowers the rate‐determining barrier to below 0.3 eV via an Eley–Rideal route, yielding rapid CO₂ formation at ambient conditions. Complementing this, studies of boron nitride cages with homonuclear B–B bonds have revealed that isolated boron sites can anchor O₂ and CO, facilitating Langmuir–Hinshelwood oxidation with energy barriers comparable to noble‐metal catalysts. These findings underscore the potential of non‐metal single‐atom centres and doped supports in achieving cost‐effective and stable CO oxidation catalysts.

Single-Atom Catalysis Mechanisms for CO Oxidation publication trend

The graph below shows the total number of articles in single-atom catalysis mechanisms for co oxidation across all publications each year (not limited to Nature Index journals).

Technical terms

Single‐atom catalyst: A catalyst in which individual atoms are isolated on a support, maximising metal utilisation and offering distinct electronic states.

Langmuir–Hinshelwood mechanism: A reaction pathway where both reactants first adsorb onto the catalyst surface before reacting.

Eley–Rideal mechanism: A pathway in which a gas‐phase molecule reacts directly with a species already adsorbed on the catalyst.

Charge transfer: The movement of electronic charge between the catalyst support, single atom and adsorbed molecules, critical for activating reactants.

Rate‐determining step: The slowest elementary step in a reaction mechanism that controls the overall reaction rate.

References

1. First Principles Study on the CO Oxidation on Mn-Embedded Divacancy Graphene. Frontiers in Chemistry (2018).
2. Activation of CO and CO2 on homonuclear boron bonds of fullerene-like BN cages: first principles study. Scientific Reports (2015).
3. The formation and evolution of carbonate species in CO oxidation over mono-dispersed Fe on graphene. Physical Chemistry Chemical Physics (2021).
4. Fe@χ3-borophene as a promising catalyst for CO oxidation reaction: A first-principles study. Frontiers in Chemistry (2022).
5. Theoretical study of metal-free catalytic for catalyzing CO-oxidation with a synergistic effect on P and N co-doped graphene. Scientific Reports (2022).