Abstract
Design of the molecular environment of single atom catalysts (SAC) is promising for achieving high catalytic activity without expensive and scarce platinum-group metals (PGM). We utilize a first principles approach to examine how the spin state of the SAC and reactants can affect catalytic energy barriers of V, Fe, Mo, and Ta on two different graphene defects with differing magnetic moments. Spin polarized projected density of states and climbing image nudged elastic band calculations demonstrate relatively lower activation energy barriers for systems with higher spin state asymmetry near the Fermi energy; CO oxidation on Ta and V SAC have decreases in activation barrier energies of 27% and 44%, respectively.Graphic
Highlights
Single atom catalysis is widely studied to minimize the amount of catalyst material while simultaneously maximizing performance
By calculating the activation energy barriers of CO oxidation reactions facilitated by these stabilized single atom catalysts (SAC) through a modified Eley–Rideal pathway, we found that all four metals have energy barriers < 1 eV on both defect types and significantly the pyridinic N dopant accesses energy barriers below 0.8 eV for all metals
Compared to our previous work modelling the same reaction with single atom Pt for a Langmuir–Hinshelwood pathway, V on N1 is comparable to the performance of a Pt surface [70] and is the most competitive with SAC Pt catalysts [17, 71] with an activation energy of 0.55 eV
Summary
Single atom catalysis is widely studied to minimize the amount of catalyst material while simultaneously maximizing performance. Orellana examined spin-constrained, non-equilibrium chemical pathways of O2 dissociation on transition metal SAC supported on a double vacancy N doped graphene defect and found small energy differences (below 0.1 eV) at points along these pathways increase the probability of spin-crossing during the reaction, enabling lower reaction barriers over spin-conserved reactions [29]. Our work expands this perspective to examine the magnetic moment of the surface defect and the TM and how this affects bonding energy. Spin state asymmetry provides new avenues for tailoring the molecular environment of promising support structures for SAC and guides choices for further experimental analysis, opening up additional lower energy chemical pathways for catalysis
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
