High surface area 3D nanowire-networks as nanoreactors for gas phase CO2 reduction and homogeneous catalysis

To fulfil the increasing energy demand and at the same time decrease greenhouse gas emissions to avoid more severe consequences of global warming is one of the biggest challenges that our society is facing today. Fortunately, there is an increasing awareness of the importance to keep the temperature rise below +2oC above pre-industrial levels and reducing as well as putting a price on CO2 emissions has moved into the spotlight of the general public. At imec we see this momentum as a huge opportunity for new technology development that transforms CO2 from an unwanted product to a valuable precursor with an economic value. Therefore, a strong focus of our work are concepts for conversion of CO2 into high value building blocks for the chemical industry. 

A very attractive possibility is to convert CO2 (CO2RR) directly by electrocatalytic reduction to valuable carbon compounds such as CO, CH4 and formic acid as well as short-chain hydrocarbons like ethylene or alcohols. Products such as CO or ethylene can then be used in a homogeneous catalytic reaction to obtain important higher hydrocarbon chemicals. Such a strategy provides a sustainable alternative to the fossil-based production of base chemicals. Unfortunately, the CO2RR is still far from practical industrial implementation and more research is necessary towards stable, highly active and selective electrodes for the electrocatalytic reaction. 

The PhD project will focus on the development of high surface area 3D-nanowire networks (nanomesh) as CO2RR electrodes and nanoreactors for homogeneous catalysis. A major part of these project is the fabrication of different metal-based nanomesh electrodes by plating in 3D-porous aluminum oxide templates. Since the surface texture plays a vital role in CO2RR product selectivity different plating bath composition & deposition conditions as well as post-deposition strategies will be explored. The surface can be further modified by thin coatings using electrochemical techniques. Next to the fabrication of the 3D-networks the student will develop a fundamental understanding of mass transport and confinement effects inside these complex nanostructured electrodes using electrochemical analysis techniques. With this knowledge the final goal is to develop a high-throughput CO2-electrolyzer that directly operates from the gas-phase making use of the high surface area of the nanomesh. Different integration strategies of the nanomesh electrodes and a solid electrolyte will be investigated to obtain high efficiencies towards the desired CO2RR products.