Research Topics

General Scope

My research focuses on reversible gas–solid thermochemical reactions, which can be generally expressed as:

A(s) + ΔH ⇌ B(s) + C(g) (Eq.1)

Under specific temperature and pressure conditions, solid A decomposes into solid B and gas C (e.g., O₂, CO₂, H₂O). This forward reaction is typically endothermic, absorbing heat from the surroundings. When the reaction conditions—temperature, the partial pressure of C, or both—are altered, solid B reacts with gas C to re-form solid A. This reverse reaction is generally exothermic, releasing heat to the environment.

Typical Reaction Systems

Based on this reversible behavior, gas–solid thermochemical reactions play an essential role in energy storage and gas separation/recovery. The systems I currently focus on include the H₂O system (Eq.2), O₂ system (Eq.3), and CO₂ system (Eq.4). These reactions can be applied to Thermochemical Energy Storage (TCES) as well as Carbon Dioxide Capture, Utilization, and Storage (CCUS).

• Ca(OH)₂(s) + ΔH ⇌ CaO(s) + H₂O(g) (Eq.2)
• Co₃O₄(s) + ΔH ⇌ 3CoO(s) + 1/2 O₂(g) (Eq.3)
• CaCO₃(s) + ΔH ⇌ CaO(s) + CO₂(g) (Eq.4)

For the O₂ system, the decomposition product B can also function as an oxygen carrier (OC), enabling further applications in Chemical Looping Combustion (CLC) and Thermochemical Water Splitting (TWS) for hydrogen production.

In TCES, the primary metrics include gravimetric and volumetric energy storage density (kJ·kg⁻¹, kJ·L⁻¹).
In CCUS, the key concern is the CO₂ uptake capacity (kg-CO₂·kg⁻¹-abs, kg-CO₂·L⁻¹-abs).
Despite the different application targets, both systems share common evaluation factors such as reaction rate, cycling stability, toxicity, and cost.

Research Methodology and Core Concerns

Research on gas–solid thermochemical systems requires a multi-scale approach:

1. Materials Development

The goal is to develop materials with high structural stability, excellent cycling durability, and cost-effectiveness. Typical materials include metal hydroxides (Me(OH)_x), metal oxides (MeO_x), and carbonates (MeCO_x). Doping strategies and micro-/macro-structural engineering are widely used to enhance energy density, reaction rates, and heat transfer.

2. Reaction Kinetics Analysis

TGA and DSC techniques are used to evaluate reaction behavior and extract kinetic parameters such as rate constants and activation energies. These parameters support the development of kinetic models, which in turn provide essential input for reactor design.

3. Reaction Module and Reactor Design

Beyond conventional packed-bed reactors, structured modules such as honeycomb monoliths and porous foams have gained attention due to their high reactivity and low pressure drop. Fluidized-bed and stirred-bed reactors are also explored to mitigate sintering and agglomeration issues. Across all designs, optimizing heat/mass transfer and improving energy density and cycling efficiency remain central objectives.

4. System Integration and Optimization

Energy and mass balance calculations enable integration of thermochemical reaction systems into target applications, including waste heat recovery, solar-thermal power systems, and CO₂ capture and utilization processes.

New Approaches (AI for Chemical Engineering)

With advancements in computational chemistry (e.g., DFT), numerical simulation, and machine learning (ML), several new methodologies have emerged:

• Using DFT to compute material stability, reaction enthalpy, oxygen vacancy formation energies, and other key properties
• Constructing hybrid datasets combining DFT calculations and experimental measurements to train ML models for high-throughput materials discovery
• Developing soft-sensor models that integrate numerical simulation and experimental data, enabling real-time prediction of variables that cannot be directly measured by physical sensors

These approaches significantly accelerate research progress and practical deployment of gas–solid reversible thermochemical technologies in energy systems and carbon-neutral applications.