How Multiphase Catalysts Power Our World
Atomic-scale revelations transforming industrial chemistry
Every day, unseen chemical transformations shape our world—from the fuel powering vehicles to the fertilizers growing our food.
At the heart of these transformations stand catalysts: substances that accelerate chemical reactions without being consumed. Among them, multiphase catalysts reign supreme in industrial chemistry, where they orchestrate reactions between solids, liquids, and gases simultaneously. Imagine a bustling factory where raw materials enter as unruly crowds and exit as precision products; multiphase catalysts are the master conductors enabling this molecular choreography.
Recent breakthroughs in atomic-scale mapping and operando spectroscopy have unveiled a hidden universe where catalysts are far more dynamic than we ever imagined—changing identities like chemical chameleons to meet industrial demands 1 3 .
Advanced imaging reveals catalysts as dynamic entities that adapt their structure during reactions, challenging decades of static models.
At the core of every catalyst lie active sites—atomic arenas where reactant molecules meet and transform. Traditional catalysts like platinum distribute these sites across their surface.
But a revolution is underway: single-atom catalysts (SACs) now isolate individual platinum atoms on solid supports, maximizing efficiency while minimizing cost 1 . These atomically dispersed catalysts are like solo virtuosi, each perfectly positioned for maximum impact.
Catalysts rarely work alone. They rely on porous supports—materials like:
These supports do more than stabilize catalysts; they create specialized environments that concentrate reactants, much like a magnifying glass focuses sunlight 2 4 .
True magic happens when components collaborate. A groundbreaking 2025 study revealed how a polyoxoniobate (PONb) catalyst combines three elements:
Activates oxygen molecules
Provides basic reaction environment
Enables mass transfer between phases
This trifecta achieves 98% aldehyde oxidation at room temperature—a previously impossible feat 4 . Such synergy exemplifies the "whole exceeding the sum of parts" in multiphase catalysis.
For decades, scientists assumed catalysts swiftly transitioned to optimal "active states" during reactions. Advanced imaging techniques have shattered this illusion.
At the Fritz Haber Institute, researchers tracked copper oxide (Cu₂O) nanocubes during nitrate-to-ammonia conversion. To their astonishment, the cubes didn't transform into pure copper metal as expected. Instead, they persisted as a dynamic mixture of metallic copper (Cu), copper oxide (CuO), and copper hydroxide (Cu(OH)₂)—a state maintained for hours 3 6 .
| Electric Potential (V) | Dominant Phase | Ammonia Selectivity |
|---|---|---|
| -0.2 | Cuâ‚‚O (pristine) | 12% |
| -0.5 | Cu/CuO mixture | 68% |
| -0.8 | Cu(OH)â‚‚-rich | 41% |
This mixed-phase state—governed by voltage, chemical environment, and reaction time—proved critical for ammonia production. At -0.5V, the Cu/CuO interface provided optimal sites for nitrate binding and hydrogenation, boosting ammonia yield 5-fold over pure phases 6 .
Converting waste nitrates into ammonia offers a sustainable path for fertilizer production. A landmark 2025 experiment at the Fritz Haber Institute revealed why copper-based catalysts outperform expensive alternatives—and how their true identity hides beneath the surface.
Scientists deployed a symphony of advanced techniques:
| Technique | Resolution | Information Obtained |
|---|---|---|
| EC-TEM | 1 nm | Particle morphology, dissolution |
| X-ray Microscopy | 30 nm | Chemical state mapping (Cuâ°/Cu²âº) |
| Operando Raman | 1 μm | Molecular bonds (Cu-OH, Cu-O vibrations) |
Results showed that under reaction conditions:
Surface reduction to metallic Cu occurred within minutes
Core oxidation simultaneously generated Cu(OH)â‚‚
Redox kinetics created a metastable hybrid phase
This explained why identical starting materials yielded different catalyst structures—a phenomenon previously attributed to "batch variability." As Dr. See Wee Chee noted: "This mixed state persists indefinitely during operation—we must design catalysts not for their initial state, but for their working personality" 6 .
Automotive catalytic converters epitomize multiphase excellence:
Advanced designs now achieve >99% pollutant conversion at cold start—a feat enabled by zeolite supports trapping hydrocarbons until catalysts warm 9 .
The 2025 polyoxoniobate (PONb) catalyst exemplifies sustainable design:
Its success lies in mimicking enzyme behavior: cobalt sites activate Oâ‚‚ like metalloenzymes, while niobium-oxo clusters function as protein scaffolds 4 .
Water electrolysis for green hydrogen relies on triple-phase boundary catalysts:
Machine learning now accelerates discovery: A 2025 model predicted HER catalysts using just 10 features, slashing computational time by 200,000x vs. traditional methods 7 .
| Reagent/Technique | Function | Innovation |
|---|---|---|
| Operando Spectroscopy | Tracks catalyst structure during reaction | Reveals transient states (e.g., Cu-CuO mixtures) |
| Single-Atom NMR | Maps atomic environments of metal sites | Resolved Pt anchoring modes in SACs 1 |
| DFT-ML Hybrid Models | Predicts adsorption energies | 92.2% accuracy with minimal features 7 |
| Polyoxometalates (POMs) | Tunable oxidation/reduction mediators | Enable Oâ‚‚ activation at room temp 4 |
| Electrochemical TEM Cells | Visualizes catalysts in liquid environments | Captured Cuâ‚‚O restructuring dynamics 6 |
The discovery of "kinetically trapped" catalyst states opens an engineering frontier: intentionally maintaining hybrid phases for superior performance. ETH Zurich's NMR-based atomic mapping now guides such designs, with platinum SACs tailored for specific coordination environments 1 .
"Closing the operando gap—between lab conditions and industrial reality—will unlock catalysts designed for stability under chaos"
Multiphase catalysis is evolving from a static science to a dynamic art. Once seen as passive participants, catalysts now reveal themselves as responsive entities, adapting their structure to reaction conditions. This paradigm shift—from designing for a fixed state to designing around adaptive behavior—holds the key to sustainable chemistry.
As research merges atomic-scale mapping with machine learning and operando insights, we advance toward catalysts that self-optimize like living systems: efficient, resilient, and exquisitely tuned to our planet's needs. In this invisible realm of dancing atoms, science is learning not just to choreograph reactions, but to teach catalysts new steps—one phase at a time.