Precise electronic structure modulation on MXene-based single atom catalysts for high-performance electrocatalytic...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic CO2 reduction reaction (CO2RR) to CO offers a sustainable pathway for carbon neutrality.
• MXene-based single-atom catalysts (SACs) are promising for CO2RR due to their tunable electronic properties.

Purpose of the Study:

• To explore Ti2CO2 and oxygen vacancy-containing Ti2CO2 MXene-based transition metal single-atom catalysts (SACs) for efficient CO2RR.
• To identify high-performance catalysts for CO2 reduction to CO with enhanced selectivity.

Main Methods:

• Computational screening of transition metal SACs on Ti2CO2 and oxygen-deficient Ti2CO2 (O_v-Ti2CO2) substrates.
• Density Functional Theory (DFT) calculations to determine limiting potentials (U_L) and reaction pathways.

Main Results:

• Sc/Ti/V/Cr-Ti2CO2 and Ni-O_v-Ti2CO2 were identified with U_L > -0.50 V.
• Ni-O_v-Ti2CO2 exhibited excellent CO2RR activity (U_L = -0.27 eV) and selectivity over hydrogen evolution and HCOOH production.
• A novel descriptor, TM-Ti-O group valence state, was proposed, with a valence state around 0.64 e- being optimal for CO2RR.

Conclusions:

• Oxygen vacancy-containing Ti2CO2-based Ni SAC is a promising catalyst for CO2RR to CO.
• The proposed electronic structure design principle can guide the development of MXene-based SACs for CO2RR.