(4do) Electrochemical Pathways to Sustainability: Impaired Water and CO2 Electrolysis

My Chemical Engineering background compels me to develop technologies that are both of holistic practical relevance and aimed at commercially desired performance. In an effort to transition towards a post-carbon economy, many countries have redirected focus on diversifying energy sources through investments in renewable energy generation technology, including green hydrogen (H₂) which has been investigated for use in an array of carbon-heavy industries. A key predicament facing commercial water electrolyzers to date remains to be upstream upsets to feed water quality which results in electrocatalytic deterioration and membrane degradation within the electrolyzer stack.

To that end, during my Ph.D. research with Prof. Abdel-Wahab and Prof. Perla Balbuena in the Department of Chemical Engineering at Texas A&M University, I focused on fundamentally understanding and developing effective surface catalytic strategies towards direct seawater electrolysis (DSWE). Notwithstanding, a plethora of selectivity, stability, and kinetic challenges under kinetically limiting and impurity rident near-neutral pH seawater face both the anodic and cathodic electrodes during DSWE. Although early technoeconomic analysis I performed showcased that desalination and deionization adds 1-2% to the total levelized cost of H₂, I believed that solving such catalytic challenges under DSWE can fundamentally result in more cost-effective and resilient materials for pure water electrolysis.

During that journey, and through a three-year ~$ 300k collaboration effort with Prof. Ted Sargent’s lab (University of Toronto) and Professor Daniel Esposito (Columbia University), I was able to lead the research effort in developing benchmark materials for both durable cathodic hydrogen evolution reaction (HER) and selective anodic oxygen evolution reaction (OER) under neutral pH seawater conditions. This was in part through first principle density functional theory (DFT) calculations I conducted under the supervision of world expert Prof. Perla Balbuena and through in-situ material characterization (i.e., XAS) insight conducted on the samples. For instance, I discovered that to prevent chloride ions from reaching the catalytic surface of the anodic catalyst, which would result in undesired chlorine evolution reaction (CER), a nickel sulfide interlayer can be used underneath the OER active catalytic layer. During anodic potentials, the crystalline sulfide transforms into a quasi-amorphous polyanionic sulfate/sulfite overlayer which electrostatically repels anionic chloride but also allows water molecules to favorably pass through and get oxidized.

Similarly, to solve kinetically limiting water dissociation under neutral pH condition, I developed a homogenous surface heterointerfaced strategy such that neighboring sites on the catalytic surface contain high degrees of electronegativity, whilst maintaining active site identity towards HER/OER. The high degree of neighboring surface electronegativity effectively allows for electron charge localization to occur, creating neighboring surface sites of high binding affinities towards hydroxide and proton, respectively. An incoming water molecule therefore gets dissociated kinetically more facilely – as confirmed through electrochemical Tafel slopes and DFT. This strategy has become widely adopted for neutral pH electrolysis, which was otherwise an untrodden field due to the kinetically more lucrative performance under extreme pH conditions.

Coupling some of these neutral pH water electrolysis challenges with water treatment processes, I also co-invented a US patent (US20230399245A1) which utilized both pressure-retarded osmosis (PRO) technology with water electrolysis for a perpetual indirect seawater electrolysis (ISWE) system that does not require buffer addition during electrolysis. After successfully defending my Ph.D., I spent the last two months working on three proposals, all of which were funded. Briefly, Academic Research Grant (ARG; ARG01-0511-230133) sponsored by Qatar Research Development Index (QRDI), an industry collaboration with ConocoPhillips Global Water Sustainability Center (GWSC), and an internal seed grant.

In my current research postdoctoral research with Prof. Ying Li in the Department of Mechanical Engineering at Texas A&M University, my research interest is on another form of electrolysis – namely gas phase CO₂ electrolysis to C2+ products such as ethylene. What is interesting is that I specifically targeting flue-gas electrolysis directly from point sources, with much lower partial pressures of feed CO₂ and impurities (O₂, SOx, NOx, etc.). In doing so, I am using both high-throughput DFT, ab initio molecular dynamics (AIMD), and machine learning (ML) to explore an integrated hybrid gas diffusion electrode (GDE) for pre-concentrating the low partial pressure CO₂ in a sorbent layer, followed by tandem GDE electrolysis (i.e., CO₂-CO-C₂H₄). I believe this work once completed will be pivotal towards global economically incentivized decarbonization. Furthermore, I am currently working on several proposals during my postdoctoral research: an NSF ERC, ARPA-E, USDA-NIFA-AFRI, and an ACS-ND.

Research Interests:

On top of water electrolysis and CO₂ electrolysis research, both from a catalysis and electrolyzer level design, I am interested in electrochemical water treatment of emergent contaminants (i.e., PFAS), direct thermochemical valorization of CO₂ to solid carbon nanoproducts, and coupled/tandem electrosynthesis. For example, if the typically undesired methane is produced during electrochemical CO₂ reduction, the anodic water oxidation reaction can be replaced with chloride or bromide oxidation to yield Cl₂ or Br₂, which in turn can chemically react with the cathodically produced hydrocarbon to generate chloro- or bromomethane – a much more valuable product compared to CH₄ or Cl₂ independently.

Teaching Interests:

My preference includes undergraduate and graduate level thermodynamics and kinetics & reaction engineering which are good fits with my research interests. Further, I would be very interested in developing both ‘electrochemistry for chemical engineers’ and ‘corrosion for chemical engineers’ elective courses. I believe such courses are becoming increasingly more important with the industrial transition towards electrification and electrochemical production routes. During my Ph.D., I have been the teaching assistant for undergraduate thermodynamics for several years, as well as industrial catalysis for a semester with the ‘father of industrial catalysis’ – Prof. Dragomir Bukur. I have also mentored tens of undergraduate and graduate students during both my Ph.D. and currently during my postdoctoral journey.

Keywords: Heterogenous Catalysis, Electrochemistry, CO2 Reduction, Hydrogen Production