Achieving a sustainable energy economy is undoubtedly one of the biggest challenges of the 21st century. The Higgins Lab at McMaster University focuses on addressing this challenge through the design, synthesis and characterization of novel nanomaterial catalysts, and their integration into electrochemical devices, such as fuel cells, batteries, electrolyzers or supercapacitors. Nanomaterial catalysts and electrochemical devices will be integral parts of a sustainable energy economy, as they will enable the interconversion of electrical and chemical energy. Put simply, they harness renewable sources of electricity (wind, solar, hydro) to produce the fuels and chemicals that society depends upon.
Students in the Higgins group apply catalyst design principles (i.e., an understanding of what makes a catalyst good) to synthesize nanomaterial catalysts designed on the atomic scale to possess desirable structures and properties. The nanomaterial catalysts are then tested for electrochemical activity towards small molecule conversions, focusing on the use of environmentally abundant molecules as reactants (i.e., O2, N2, H2O, CH4) to produce fuels, chemicals and fertilizers. Catalyst structure-property-performance relationships are established through extensive spectroscopic and microscopic nanomaterial characterization using advanced techniques available at McMaster University, including at the state-of-the-art Canadian Centre for Electron Microscopy facilities. Best in class nanomaterial catalysts are integrated into working electrochemical device prototypes that are engineered for performance validation and demonstration.
Some of the current electrochemical reactions and technologies of interest in the Higgins group include:
Electrochemical reduction of CO2 to produce carbon-based fuels and feedstock chemicals
Operando / in situ characterization of electrocatalyst and electrode materials
Rechargeable Zn-ion batteries for grid scale energy storage
Water electrolyzers for sustainable hydrogen production
Low temperature fuel cells for transportation application
Electrochemical production of hydrogen peroxide for water treatment applications
Electrochemical activation and conversion of natural gas to produce value added fuels and chemicals
Value added anodic processes
Keywords: Electrochemistry, electrocatalysis, CO2 conversion, fuel cells, electrolysis, nanomaterials, sustainable energy, energy conversion and storage, operando characterization, in situ characterization, X-ray absorption spectroscopy, transmission electron microscopy, batteries, supercapacitors
A warm welcome to Shanquan and Salma who recently joined us in January 2022.
Congratulations to Fatma for publishing her paper in the journal of ACS, Applied Energy Materials.
We have developed nickel-nitrogen-carbon (Ni-N-C) catalysts from metal organic framework precursors for the electrochemical conversion of CO2. We investigate the role of synthesis parameters on the resulting properties and performance of the catalyst materials, which were found to be heterogeneous in structure and composition. The optimized Ni-N-C catalysts provide high activity and selectivity for the electro-conversion of CO2 into CO, likely due to the presence of atomically dispersed Ni-Nx/C sites within the catalyst structure.
F. Ismail, A. Abdellah, H. Lee, V. Sudheeshkumar, W. Alnoush, D. Higgins, “Impact of Nickel Content on the Structure and Electrochemical CO2 Reduction Performance of Nickel–Nitrogen–Carbon Catalysts Derived from Zeolitic Imidazolate Frameworks”, ACS Applied Energy Materials.
The development and implementation of in situ / operando characterization techniques provides the capability to image electrochemical processes while they are occurring, establish structure-property-performance relationships and elucidate the properties of electrified interfaces. However these measurements are predicated on the ability to accurately and reliably control the electrochemical potential of the working electrode, which is dictated by the reference electrode used during experiments. In this perspective paper we discuss the use of reference electrodes (including quasi-reference electrodes) for operando characterization of electrochemical processes, provide practical tips, highlight challenges and identify prospective opportunities for the selection, validation and use of reference electrodes during operando experiments.
W. Alnoush, R. Black, D. Higgins, “Judicious selection, validation, and use of reference electrodes for in situ and operando electrocatalysis studies”, Chem Catalysis.