A spin-crossover-mediated potential-dependent selective NO reduction reaction on iron-polyphthalocyanine: a DFT study

Area of Science:

• Electrocatalysis
• Materials Science
• Computational Chemistry

Background:

• Nitric oxide electrochemical reduction (NORR) offers dual benefits: pollution control and sustainable ammonia synthesis.
• Iron-polyphthalocyanine (FePPc) shows promise for NORR, but its spin-involved mechanism and selectivity determinants are unclear.
• Spin-dependent effects in single-atom catalysts are understudied, hindering fundamental understanding.

Purpose of the Study:

• Investigate the NORR mechanism on FePPc using DFT.
• Clarify the role of spin states and spin crossover in product selectivity (NH3 vs. NH2OH).
• Explore spin-activity relationships in graphene-based single-atom catalysts.

Main Methods:

• Constant-potential density functional theory (DFT) calculations.
• Analysis of reaction pathways and intermediate spin states.
• Investigation of potential-dependent spin crossover phenomena.

Main Results:

• Key intermediates exhibit potential-dependent spin states, undergoing spin crossover at critical steps.
• Potential-driven spin crossover dictates reaction trajectory and product selectivity.
• FePPc's selectivity shifts between NH3 and NH2OH based on applied potential.

Conclusions:

• Spin crossover is essential for understanding and controlling NORR product distribution under electrochemical conditions.
• Spin states play a critical role in tuning the selectivity of single-atom catalysts for nitrogen oxide reduction.
• Spin engineering emerges as a key principle for designing advanced electrocatalysts.