Metal-Molecule Interactions Govern CO₂ Reduction with Potential-Dependent Charge Transfer Effects.

Area of Science:

• Electrochemistry
• Materials Science
• Computational Chemistry

Background:

• Molecular catalysts offer precise active sites but their performance is substrate-dependent.
• Understanding substrate effects on catalytic activity, especially under electrochemical conditions, is crucial.
• Applied potential dynamically alters interfacial electronic structure, impacting catalyst behavior.

Purpose of the Study:

• To investigate how metal substrates regulate CO2 reduction activity of transition-metal phthalocyanines (TMPcs).
• To elucidate the mechanisms by which substrates and applied potential influence catalytic performance.
• To provide design principles for supported molecular catalysts.

Main Methods:

• Density functional theory (DFT) calculations.
• Constant-potential simulations.
• Systematic investigation of TMPcs (FePc, CoPc, NiPc) on various metal substrates (Au, Ag, Pt).

Main Results:

• Metal substrates regulate activity via static charge state tuning and potential-driven dynamic charge transfer.
• Electron transfer at the metal center effectively describes *CO adsorption and activity trends.
• Metallic substrates act as charge reservoirs, dynamically modulating active sites under applied potential.
• CoPc/Pt(111) shows favorable CO2 reduction at -0.6 V vs RHE, unlike graphene-supported CoPc.

Conclusions:

• Both substrate type and applied potential are critical for molecular electrocatalyst activity.
• Dynamic charge transfer from metallic substrates significantly enhances CO2 reduction.
• Design principles for supported molecular catalysts can be derived from understanding these substrate-catalyst interactions.