Research

The Hu lab studies particle photocatalysts as a generic materials platform for scalable chemical production: for example, particulate photocatalysts that are suspended in water or sprayed onto a panel can readily convert light energy to chemicals. We focus on understanding non-equilibrium, reversible light-driven processes of chemical catalysis or materials synthesis, at a photoelectrochemical (PEC) interface.

In the viewpoint of physical chemistry, we need to understand non-equilibrium, reversible light-driven processes of chemical catalysis or materials synthesis, at a photoelectrochemical (PEC) interface. Our research group at Yale designs and demonstrates PEC devices, consisting of key functional components, such as semiconductor photocatalysts, liquid electrolytes and chemical reactants. 
 
Regarding our approach, we rather not track every pathway of excited-state charge dynamics and charge-transfer kinetics, because unlike molecular systems, particles calculations are too complicated and we also risk losing a clear narrative for how they operate. Our research scope is to elucidate particles operation by connecting charge dynamics inside particles to charge-transfer kinetics at particle/liquid interfaces. 
 
Broadly, 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, ammonia synthesis by N2 reduction to make fertilizer, and so on. We are interested in finding out the governing rules of running a light-driven artificial photo-synthetic system efficiently and designedly
 

We are currently interested in the following areas:

  • Electronic Structure Tuning for Photocatalysis and Electrocatalysis

  • Multi-Functional Coatings

  • Non-Equilibrium Rate Processes at Semiconductor Photocatalysts

  • Scalable Synthesis of Nanoscale Semiconductors and Synergistic Effects with Oxide Catalysts

  • Modeling and Experiments Towards Solar-to-Fuel Conversion Devices

Regarding our approach, we rather not track every pathway of excited-state charge dynamics and charge-transfer kinetics, because unlike molecular systems, particles calculations are too complicated and we also risk losing a clear narrative for how they operate. Our research scope is to elucidate particles operation by connecting charge dynamics inside particles to charge-transfer kinetics at particle/liquid interfaces. 
 
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. To support building a multi-physics model to eventually simulate these processes, we employ in situ microscopic and spectroscopic techniques to  interrogate materials/electrolyte interfaces at meso-to-nano-scale. 
 
Many applications rely on this PEC device’s functional interface: converting sunlight, water, and air into energy-dense fuelsguiding additive materials growth or subtractive photo-corrosion; or even making the PEC interface self-repair. Therefore, we consider a light-driven PEC device as an open, living system especially with free and abundant sunlight in our macroscopic world as the energy inputs.

We also build photoelectrochemical devices that simultaneously achieve energy storage and water treatment, for a clean and sustainable world!