Theoretical studies on the BC₂N monolayers with promising photoelectronic characteristics and remarkable environmental stabilities

Abstract

In this study, density functional theory calculations were performed to investigate the geometric structures, thermodynamic and mechanical stabilities, electronic, and optical properties of two BC 2 N monolayers with honeycomb structure. The computational results demonstrate that the BC 2 N monolayers have not only visible-light absorption, but also high reducing capacity of photo-induced electrons and excellent carrier mobility. Also, ab initio molecular dynamics simulations with considering the O 2 and H 2 O molecule were carried out, which suggest that the crystal structures of both BC 2 N monolayers can be well maintained in the moisture-laden air filled with O 2 molecules at 800 K. Accordingly, these BC 2 N monolayers with promising photoelectronic characteristics and environmental stability could be utilized as metal-free visible-light-driven photocatalysts in high-temperature environment with moisture and oxygen, which is worthy of being further investigated in experimental and theoretical studies.absorption, carrier mobility, environmental stability, photocatalyst, thermodynamic stability | INTRODUCTIONSince the discovery of photocatalysts, a great deal of studies has been performed to investigate the electronic and structural properties of these materials. Visible-light-driven photocatalysts are an attractive research topic in the fields of pollution removal and fuel production, because of the potential to employ sunlight to promote reactions under very mild conditions. Sparked by the discovery of graphene, massive two-dimensional (2D) materials possessing sheet like structures with only single-atom or few-atom thickness have been experimentally realized and applied in varieties of applications, among which a great deal of success have been achieved in 2D photocatalysts. [1] When 2D materials are used as photocatalysts, they have several inherent advantages in improving photocatalytic efficiency. The advantages include such aspects: reduced migration distance and promoted separation of photo-activated e − -h + pairs, the high specific surface area for light absorption, conveniently regulable electronic and optical properties. [2][3][4][5] Up to present, there are numerous strategies to obtain 2D photocatalysts, among which two methods are usually used to gain graphene-like or graphene based photocatalysts. The first one is to select 2D semiconductors with appropriate optoelectronic properties, such as phosphorene, g-C 3 N 4 , MoS 2 , and WS 2 monolayers. [6,7] For instance, Wang et al. demonstrate that ultrathin black phosphorus (BP) nanosheets exhibit an exotic, excitation-energy-dependent, optical switching effect in photocatalytic reactive oxygen species (ROS) generation. [8] Their work not only establishes an in-depth understanding on the influence of many-body effects on photocatalysis, but also paves the way for optimizing catalytic performances via controllable photoexcitation. The other strategy to achieve 2D photocatalytic materials is based on graphene materials, including graphene doped by met...

g‐B3C2N3: A Potential Two Dimensional Metal‐free Photocatalyst for Overall Water Splitting**

“…However, the electronegativity difference and hence the degree of localization is much less as compared to the h‐BN system. This justifies the band gap value to be intermediate to that of semimetallic graphene and insulating h‐BN (5.9 eV), [27] which is consistent with the electronic properties of most of the materials of this B‐C‐N class [31,38,39] …”

“…So a uniform distribution of B,C and N can unveil new physics and broaden the range of applicability. From first principle calculations it is predicted that such systems, e. g. BC 2 N , [38] BC 6 N [39] have a promising prospect in photocatalysis. But a uniform distribution of B, C and N demands extremely controlled synthesis conditions and is difficult to achieve experimentally in general.…”

Optical–Acoustic Phonon Hybridization Enhanced Thermoelectric Performance in a 1T′ Phase OsTe2 Monolayer

“…The environmental stability of the OsTe 2 monolayer with respect to oxidation and moisture is also tested by the AIMD simulation with added oxygen and water molecules in the vacuum space of the supercell. This method has been used to test the environmental stability of two-dimensional materials . The equilibrium of the OsTe 2 monolayer structure is obtained in Figure S2.…”

“…This method has been used to test the environmental stability of two-dimensional materials. 44 The equilibrium of the OsTe 2 monolayer structure is obtained in Figure S2. Apparently, oxygen and hydrogen atoms are only adsorbed on the surface of the OsTe 2 monolayer and could not destroy its framework.…”

Square-Octagon Structure of a BCN Monolayer: Near-Zero Poisson’s Ratio, High Carrier Mobility, and Excellent Photocatalytic Activity for Overall Water Splitting

“…For instance, the B x C y N z nanosheets such as N- and B-doped graphene showed good performance in an electrochemical hydrogen evolution reaction (HER) but are not ideal photocatalysts for overall water spilling because their valence band minimum is located above the redox potentials for O 2 /H 2 O . The stability of 2D ternary B x C y N z compounds has been studied theoretically, and their properties depending on both the stoichiometry and the arrangement of the B, C, and N atoms have been predicted. ,− Although these theoretical studies suggest that 2D B x C y N z may have a tunable bandgap, strong visible-light adsorption, and high carrier mobility, , only few 2D B x C y N z materials, such as B,N co-doped graphdiyne, are predicted to be effective photocatalysts for water spilling.…”