Research
Adaptive Catalysis: Catalysts as Evolving Systems
The Adaptive Catalysis Group studies catalysts as dynamic chemical systems rather than fixed structures. The material that is synthesized is only the starting state. Under reaction conditions, active sites can change their nuclearity, coordination environment, oxidation state, spatial arrangement, and interaction with the surrounding host.
Our central premise is:
Precise precursor design → controlled reconstruction → dynamic active-site ensemble → catalytic function → recovery or deactivation
We therefore ask not only what structure was synthesized, but also which structure forms under reaction conditions, why it forms, whether it is reversible, and how that structural evolution determines catalytic performance.
Scientific Question 1 — How do active sites reconstruct during catalysis?
We investigate how reactants, products, temperature, water, redox environment, and repeated catalytic cycling reshape active sites while a reaction is proceeding.
The key problem is to distinguish productive adaptation from irreversible deactivation. A change in structure may generate the catalytically competent state, but the same driving force can also lead to migration, aggregation, framework damage, or loss of active-site definition.
We focus on resolving:
- changes in metal nuclearity and local coordination
- migration, aggregation, redispersion, and site exchange
- reversible versus irreversible structural evolution
- coupling between host structure and active-site reconstruction
- structural origins of activation, selectivity changes, and deactivation
The long-term objective is to establish a reconstruction map that links reaction environment, structural state, timescale, and catalytic function.
Scientific Question 2 — Can dynamic active sites be programmed before reaction?
Catalyst reconstruction is often treated as an uncontrolled phenomenon. We instead ask whether the reconstruction pathway itself can be biased through deliberate molecular and materials design.
Low-nuclearity metal ensembles confined in porous hosts provide an experimentally tractable platform for this problem. By controlling the starting nuclearity, composition, local geometry, host topology, and surrounding coordination environment, we aim to define which structural transformations are accessible under reaction conditions.
Our design strategies include:
- atomically precise single-site, dual-site, and multinuclear metal ensembles
- homo- and heterometallic active-site architectures
- ligand-mediated and host-directed assembly
- confinement within zeolites and related porous materials
- control of local framework charge and the secondary coordination environment
The goal is not to make active sites completely rigid. Instead, we seek an adaptive window in which the site can reorganize enough to perform chemistry while remaining protected from uncontrolled migration, aggregation, and irreversible collapse.
Scientific Question 3 — Which evolving structure is causally responsible for catalytic function?
Dynamic catalysts can generate multiple structural states during a single reaction. Simply observing that two quantities change together is therefore insufficient to assign an active structure.
We treat active-site identification as a model-selection problem. Competing structural hypotheses are tested through controlled perturbations, time-resolved measurements, control experiments, and direct comparison with catalytic rates and selectivities.
Our aim is to move from static structure–activity correlations toward causal dynamic structure–function relationships.
Evidence Framework
Our research follows a recurring logic:
Structurally constrained precursor → controlled chemical perturbation → time-resolved structural observation → competing hypotheses → falsification and controls → catalytic consequence → catalyst redesign
Structural characterization is used to discriminate between mechanistic models rather than as an endpoint by itself. Depending on the problem, we combine:
- X-ray and neutron diffraction for long-range structural evolution
- total scattering and pair distribution function analysis for local and intermediate-range structure
- X-ray absorption spectroscopy for local coordination and electronic structure
- complementary spectroscopic and reaction analysis to connect structural changes with chemical function
This framework is designed to identify the working catalyst, not simply the most convenient ex situ structural model.
Research Scope
The concepts developed in the group are applied to catalytic systems where active-site structure is expected to evolve substantially under operating conditions. Current interests include porous and zeolite-confined catalysts, multinuclear metal ensembles, selective oxidation, dehydrogenation, C–N bond formation, hydrogenation, and related energy and sustainability reactions.
Across these systems, the unifying question remains the same:
Can catalyst restructuring be understood well enough to become a controllable design variable?
For representative work, see our Publication Highlights and full publication list.