Synthesis

The (photo)electrocatalytic reduction of carbon dioxide to fuels offers an efficient strategy to reduce the presence of greenhouse gases in the atmosphere while concurrently producing valuable carbon-based products. Our group has been developing the synthesis of various semiconducting light absorbers, photonic crystals and metallic electrodes with well-defined compositions, nanostructures, morphologies and advanced properties for electrocatalysis and photoelectrochemistry. We provide different examples of catalytic systems that may reveal design principles that enable development of active and selective catalysts and provide further insights into the reaction mechanism. Here are some of efforts done in our group:

Surface modifications of existing inorganic catalysts

Modifying surface of inorganic catalyst through electrodeposition and/or dropcasting modifiers on a non-precious metal catalyst shows the ability to alternately tune between CO and formic acid, and suppress hydrogen production on a non-precious metal catalyst for CO2R.

After observing series of hydrophobic and hydrophilic organic modifiers, we also found correlation of observed products with hydrophilicity/phobicity suggest that the role of water deserves careful consideration in designing modifiers for CO2R.

Design of new catalysts frameworks through Molecular Organic Frameworks (MOFs)

We present two design strategies for the synthesis of molecular organic frameworks (MOFs) and nitrogen-containing, metallated covalent organic framework (COF) as novel catalysts for CO2 reduction (CO2R). These materials platforms are highly promising as heterogeneous catalysts because they may be readily tuned by modular changes to the precursor material. This property will allow for highly selective and active carbon dioxide reduction that is challenging to achieve with traditional homogeneous and inorganic catalysts. Interestingly, these systems are also used for their excellent gas adsorption characteristics. Through the use of this material system, we can aid adsorption of CO2 and enhance its local concentration, thus promoting both capture and conversion. This unique approach will lead to increases in selectivity and activity. We will survey a library of materials to enable the development of a low cost CO2R catalyst system, thus reversing the current deleterious trend in changing climate. 

Tuning surface properties of semiconductor photocathodes

Semiconductor/electrolyte interface is the basis of a photoelectrochemical cell, where photogenerated charge carriers are migrated to driven chemical reactions. Thus, we are aiming at tuning surface properties like defects structures of semiconductors by controlled synthetic methods such as electodeposition and studying the impact of surface properties on charge transfer at the semiconductor/electrolyte interface.

Nanostructuring of (photo)electrocatalytic materials

Nanostructuring approaches of photoelectrocatalytic materials have the potential to reduce bulk recombination and improve electron–hole pair separation in semiconductor light absorbers, as well as to increase the active surface area and influence the activity in catalytic systems. We developed a versatile approach for the synthesis of reproducible, highly homogeneous, large scale nanoporous (photo)electrocatalytic materials including Cu2O, BiVO4, CuBi2O4, and Cu for artificial photosynthesis, using colloidal polystyrene beads opal templates and bottom-up infilling technique (electrodeposition).