Research – Lightcatalysis

Solar Photochemistry and Natural Resource Utilization

We investigate light-driven catalysis processes that couple with non-equilibrium cascade reactions and chemical transport in practical reactors.

Our Three Key Developments

One

The coatings for stable photocatalysis.

The coatings for stable photocatalysis

Coatings for stable photocatalysis protect semiconductor light absorbers by preventing photo-corrosion, allowing for efficient charge separation without causing electron-hole recombination, and enabling band edge adjustments.

Two

Design principles for achieving near unity quantum efficiency.

Design principles for achieving unity quantum efficiency

Design principles for achieving unity quantum efficiency focus on optimizing semiconductor doping and surface energetics, charge-transfer selectivity (branching ratio of proton reduction vs. oxygen reduction), and reactor architectures to maximize the generation and utilization of every absorbed photon.

Three

Pioneering study of catalysis and adsorption in transport flux.

Pioneering study of catalysis and adsorption under non-equilibrium chemical transport flux

We are the first to examine the interplay between chemical flux and adsorption processes in dynamic, non-equilibrium, light-driven cascade reaction systems. For example, a photocatalytic surface can involve proton-coupled hole oxidation, electron reduction, and proton-(bi-)carbonate speciation.

We have created a catalyst discovery platform that combines coating-modified photocatalysts with flow devices to efficiently produce H₂, syngas, and H₂O₂ solutions at scale. The H₂O₂ technology has been deployed at 1 m², with others currently being scaled up. Broadly speaking, these PEC devices involving semiconductors can produce not only energy-dense fuels such as hydrogen but also fine chemicals, water oxidation to make hydrogen peroxide, selective CH₄ partial oxidation to utilize hydrogen peroxide, N₂ oxidation to make fertilizer and drug precursors, and so on.

This catalyst design platform should accelerate the development of developing light-driven chemical production, an alternative to thermal catalysis.

Photoelectrochemistry

Photoelectrochemical Interface: A Novel platform for light/chemical transduction

Photocatalytic Surface

Photocatalytic Surface Chemistry: Adsorption coupled with photo-induced charge transfer

Molecular Flux Catalysis

Molecular Flux Catalysis: Non-equilibrium CO₂ photocatalysis in flowing seawater

Coating + X

Multi-Functional Coatings: Novel compositions, processing, and scale-up manufacturing

PEC Device Scale-Up

PEC Device Scale-Up: Design and manufacturing for scalable PEC Systems

AI Hardware

Energy-Efficient Analogue Computing: Photoelectrochemical Neural Network

Our Research Approach

Advancing Semiconductor Catalysis: Integrating Theory, Modeling, and Operando Characterizations for Efficient Light-to-Chemical Conversion

We take a multi-disciplinary approach, integrating electron-transfer theory, method developments, materials science, and applied mathematics to advance semiconductor catalysis science. Our research scope is to elucidate particles operation by connecting charge dynamics inside particles to charge-transfer kinetics at particle/liquid interfaces. We are interested in finding out the governing rules of running a light-driven artificial photo-synthetic system efficiently and cost-effectively.

Therefore, our research scope is to elucidate photocatalyst operation by connecting charge dynamics inside particles to charge-transfer kinetics at particle/liquid interfaces. To support the effort of quantifying photoelectrochemical (PEC) interfaces, we are building a multi-physics model to eventually simulate these processes.

Additionally, we employ in situ microscopic and spectroscopic techniques to interrogate materials/electrolyte interfaces at meso-to-nano-scale. We characterize various types of PEC interfaces, especially those stabilized with protective coatings, so that we can eventually connect charge-transfer rate processes with semiconductor device physics.

Archived Research

Particulate Photocatalysis

We, as a group, study the photocatalyst/(co-catalyst)/water interface and aim for rational design of efficient and stable photocatalytic systems.

Photocatalytic water-splitting involves light absorption, generation of electron–hole pairs, charge separation and bulk transport, charge transfer across interfaces for catalytic reactions, and mass transfer of reactants and products.

Multi-Functional Coating

We are developing multifunctional protective coatings, based on titanium dioxide (TiO₂), for various photoelectrochemical synthesis pathways and electrochromic films. Different chemical reactions requires different thermodynamic driving forces, so it is important to tune your protective coatings to match your synthesis.

Stable Photoelectrochemical (PEC) Interface

Our strategy for durability is metal oxides based heterostructure interfaces in order to achieve efficient and stable photoelectrochemical water oxidation. We developed a new class of ternary oxide coating, (Ti,Mn)O_x, for efficient charge separation and stable water oxidation in acid.

Operando Study

Through a systematic effort of monitoring photo-corrosion with operando microscopy and spectroscopy, we first understand typical photoanode corrosion process with a detailed description for the different corrosion stages. Secondly, we use our photocorrosion model to explain how various protection or corrosion behavior is manifested in shifts of surface corrosion potentials.

Tunable Nanomaterials for Catalysis

Our interests are also focusing on 2D tunable metal oxides. We collaborate with Prof. Lisa Pfefferle’s group. We use microscopy and spectroscopy to characterize materials/liquid interfaces under operating conditions.

Modeling and Simulation

Chemical Engineers rely on modern modeling and simulation tools to design and optimize reactors. Solar-fuel reactors are a type of emerging chemical reactors.