Two-dimensional MBene: a comparable catalyst to MXene for effective CO₂RR towards C₁ products

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical CO2 reduction reaction (CO2RR) is crucial for mitigating greenhouse gas emissions and addressing energy shortages.
• Two-dimensional (2D) MXene materials are recognized for their catalytic potential in electrocatalysis.
• 2D transition metal borides (MBenes), boron analogs of MXenes, offer unique electronic properties that may enhance CO2RR performance.

Purpose of the Study:

• To theoretically evaluate the potential of a novel 2D transition metal boride, MoB, as a catalyst for the CO2RR.
• To compare the CO2RR performance of MoB with the traditional catalyst Mo2C.
• To investigate the catalytic mechanisms and properties of MoB for CO2RR.

Main Methods:

• Theoretical evaluation of MoB as a CO2RR catalyst.
• Comparison of MoB with Mo2C.
• Analysis of electronic properties, including metallic nature and electrical conductivity.
• Calculation of interaction energy for CO2 activation.
• Density of states and charge difference density analysis to understand charge transfer.
• Evaluation of catalytic selectivity by considering hydrogen evolution reaction and CO2RR energy barriers.

Main Results:

• MoB exhibits metallic characteristics and excellent electrical conductivity.
• MoB demonstrates effective CO2 activation with a significant interaction energy (-3.64 eV), surpassing Mo2C.
• Substantial charge transfer from MoB to CO2 was observed, indicated by density of states and charge difference density.
• MoB shows enhanced catalytic selectivity for CO2RR due to suppressed hydrogen evolution reaction and favorable reaction energies.
• At potentials more negative than -0.62 V, MoB facilitates a high-throughput CO2RR process towards methane (CH4).

Conclusions:

• MoB presents comparable CO2RR performance to Mo2C.
• MBenes are forecasted as highly promising catalysts for electrochemical applications, including CO2RR.
• The findings highlight MoB as a novel and effective catalyst for converting CO2 into valuable products like methane.