Green Hydrogen

Green hydrogen generated from surplus renewable electricity during peak operation opens an untrodden path towards relieving energy security tensions and bridging the gap towards capitalizing on renewable energy resources, namely solar and wind. At the Water and Environmental Research Lab and under the advisement of Dr. Abdel-Wahab, the group has been actively working on the growing field of electrochemical green hydrogen production through water electrolysis both experimentally and theoretically. The general scheme of electrocatalyst design entails in-house rationalizing (theoretical backing), synthesizing, electrochemically testing, and characterizing both cathodic and anodic electrocatalysts towards the hydrogen (HER) and oxygen evolution reactions (OER). Of the many KPIs in any electrochemical energy conversion application, electrocatalytic activity is on the top of the list. Although a plethora of knowledge has been acquired over the past two decade in terms of designing electrocatalysts, benchmark materials remain to be expensive platinum-group-metal (PGM) based materials. Herein, we utilized first-principle density functional theory (DFT) towards investigating and fine-tuning fundamental key descriptors (i.e., defect-induced stability, electronic density of states (DOS) near Fermi levels, intermediates Gibbs free binding energies) such that favorable electronic modulation of an electrocatalytic surface may be ensured towards a specific half-reaction, namely HER and OER. In doing so, we have published numerous novel electrocatalysts with high activities, kinetics, stabilities, and selectivity under harsh and unconventional electrolytic conditions. To that end, with the supercomputing resources provided by the HPC-RC at TAMUQ we investigated inexpensive CoCu alloyed nanoclusters grown atop carbon nanowires (CNW) towards bifunctional performance in both HER and OER. DFT based electronic DOS calculations, showcased in the below figure (a) showcase that upon effective heterojunctions between CoCu nanoclusters and the underlying CNW, an increase in the electronic states near the Fermi level is attained which enables more facile thermodynamics for HER/OER reaction intermediates. This was also confirmed by modeling the thermodynamic reaction coordinate profile for HER and OER, shown in figure (b, c). Charge density difference (CDD) analysis in figure (d) of the OOH* rate determining step (RDS) from reaction coordinate profiles of OER atop the CoCu@CNW catalyst depict charge accumulation and depletion zones which can be used for rationalizing behavior of future iterations. The showcased material was experimentally fabricated, electrochemically tested, and results were published in Elsevier’s Journal of Industrial and Engineering Chemistry (doi.org/10.1016/j.jiec.2021.01.027).