Unveiling the atomic-level mechanisms that power 90% of industrial chemical processes
Imagine a bustling city square where strangers meet, exchange goods, and depart transformed. This is precisely what occurs on the surface of heterogeneous catalysts—solid materials that accelerate chemical reactions without being consumed themselves.
From the fertilizers that feed our world to the catalytic converters that clean our air, heterogeneous catalysis underpins approximately 90% of all chemical industrial processes 8 .
Reactant molecules land on and attach to specific sites on the catalyst surface through physisorption or chemisorption .
The adsorbed molecules undergo chemical transformations. The atomic structure of the surface determines which reactions are favored 4 .
The product molecules detach from the surface, freeing up active sites for subsequent reactions .
One of the greatest challenges in surface science has been the "pressure gap"—the discrepancy between the ultrahigh vacuum conditions required for many analytical techniques and the atmospheric or high-pressure conditions of industrial processes.
| Technique | Acronym | What It Reveals |
|---|---|---|
| Scanning Tunneling Microscopy | STM | Surface topography at atomic resolution |
| X-ray Photoelectron Spectroscopy | XPS | Elemental composition and chemical states |
| Temperature-Programmed Desorption | TPD | Binding strength of adsorbed species |
| Operando Transmission Electron Microscopy | Operando TEM | Structural changes during reaction |
In 2025, Professor Kai S. Exner and his team discovered that on iridium dioxide surfaces, oxygen production follows a 'Walden-type mechanism' where the reaction proceeds through a simultaneous rather than stepwise process 2 . This revelation fundamentally changes how scientists conceptualize surface reactions.
A groundbreaking experiment published in Nature Communications in 2025 provides a stunning example of how advanced imaging techniques are revealing previously invisible aspects of catalytic processes 3 .
Specially modified TEM with gas cell, allowing introduction of reactant gases directly into the observation area.
Direct observation of structural changes as they occurred under authentic reaction conditions.
Simultaneous monitoring of reaction products, correlating atomic-scale events with catalytic activity.
The boundary between NiFe nanoparticles and the Fe₃O₄ support migrated systematically, with the NiFe particles moving across the support surface while simultaneously consuming it 3 .
The reaction occurred at two distinct locations on a single nanoparticle: hydrogen activation at the NiFe-Fe₃O₄ interface and oxygen activation at Fe₃O₄ facet edges 3 .
| Component | Chemical Formula | Primary Role |
|---|---|---|
| Active Metal Nanoparticle | NiFe alloy | Activates hydrogen molecules; initiates reduction of support |
| Reducible Oxide Support | Fe₃O₄ (Magnetite) | Provides structural support; participates in oxygen activation |
| Interface Region | NiFe-Fe₃O₄ boundary | Site for hydrogen spillover and initial reduction |
| Migratory Species | Fe⁰ adatoms | Transport activated atoms between reaction zones |
Tools for visualizing and analyzing surfaces at atomic resolution under reaction conditions.
Theoretical methods and databases for predicting and analyzing catalytic behavior.
Advanced materials with tailored properties for specific catalytic applications.
| Category | Specific Tools/Methods | Function/Role |
|---|---|---|
| Characterization Techniques | Operando Transmission Electron Microscopy | Visualizes atomic-scale structural changes during reactions |
| Characterization Techniques | X-ray Photoelectron Spectroscopy (XPS) | Determines elemental composition and chemical states on surfaces |
| Computational Resources | Density Functional Theory (DFT) | Calculates electronic structure and reaction energetics |
| Computational Resources | Catalysis-Hub.org Database | Open repository of surface reaction data |
| Catalytic Materials | Bimetallic Alloys | Enhanced activity and selectivity through synergistic effects |
| Catalytic Materials | Reducible Oxide Supports | Participate directly in catalytic cycles |
In 2025, researchers proposed an innovative roadmap for destroying persistent "forever chemicals" using heterogeneous catalysis 5 .
Catalysis-Hub.org provides free access to over 100,000 calculated surface reaction energies, accelerating discovery 9 .
From revealing the intricate dance of atoms at catalyst surfaces to enabling the destruction of persistent environmental pollutants, surface science has transformed from a specialized field into a central discipline addressing humanity's most pressing challenges. The coming decades will witness the rational design of catalytic systems for converting greenhouse gases into valuable fuels, producing clean hydrogen from water, and synthesizing chemicals with minimal energy input and waste generation.