Nitrogen-monovacancy (VN) Hexagonal Boron Nitride 2D Monolayer Material as an Efficient Electrocatalyst for CO2 Reduction Reaction

TL;DR

This study investigates nitrogen-vacancy defective hexagonal boron nitride monolayers as efficient, cost-effective electrocatalysts for CO2 reduction, demonstrating their potential to activate CO2 and produce methane via a favorable reaction pathway.

Contribution

It introduces a novel defective 2D boron nitride monolayer with nitrogen vacancies as an effective catalyst for CO2 reduction, supported by first-principles calculations.

Findings

Defective BN monolayer reduces band gap from 6.23 eV to 3.0 eV.

Active sites are located at boron atoms in defective regions.

OCHO* pathway favors methane production.

Abstract

The conversion of waste carbon dioxide (CO2) gas into valuable products and fuels through an electrocatalytic CO2 reduction reaction (CO2RR) is a promising approach. The sluggish kinetics of the CO2RR require the development of novel strategies for electrocatalyst design. Two-dimensional (2D) materials emerge as promising candidates for CO2RR due to their distinctive electronic and structural properties. This study follows the first principles based DFT-D method to examine the electrocatalytic competences of the defective two-dimensional boron nitride monolayer (d-BN) material towards CO2RR. Introducing a particular defect with nitrogen vacancies in the 2D single layer pristine hexagonal boron nitride (VN_d-BN) can efficiently activate the CO2 molecules for hydrogenation by reducing the electronic band gap of the pristine hBN from 6.23 eV to 3.0 eV. Therefore, VN_d-BN material can act as a large band gap semiconductor. Our findings demonstrate that the defective regions in the 2D monolayer VN_d-BN serve as active sites (Boron) for both the adsorption and activation of CO2. The subsequent hydrogenation steps occur sequentially once the CO2 molecule is adsorbed on the catalytic surface. Our results indicate that the OCHO* path is the most favorable for CH4 production. Hence, the 2D monolayer VN_d-BN material holds a great promise as a cost-effective catalyst for CO2RR, and it presents a viable alternative to expensive platinum (Pt) catalysts.