Highly Efficient Photocatalytic Water Splitting over Edge-Modified Phosphorene Nanoribbons

Abstract

Two-dimensional phosphorene with desirable optoelectronic properties (ideal band gap, high carrier mobility, and strong visible light absorption) is a promising metal-free photocatalyst for water splitting. However, the band edge positions of the valence band maximum (VBM) and conduction band maximum (CBM) of phosphorene are higher than the redox potentials in photocatalytic water splitting reactions. Thus, phosphorene can only be used as the photocathode for hydrogen evolution reaction as a low-efficiency visible-light-driven photocatalyst for hydrogen production in solar water splitting cells. Here, we propose a new mechanism to improve the photocatalytic efficiency of phosphorene nanoribbons (PNRs) by modifying their edges for full reactions in photocatalytic water splitting. By employing first-principles density functional theory calculations, we find that pseudohalogen (CN and OCN) passivated PNRs not only show desired VBM and CBM band edge positions induced by edge electric dipole layer, but also possess intrinsic optoelectronic properties of phosphorene, for both water oxidation and hydrogen reduction in photocatalytic water splitting without using extra energy. Furthermore, our calculations also predict that the maximum energy conversion efficiency of heterojunction solar cells consisting of different edge-modified PNRs can be as high as 20% for photocatalytic water splitting.

Bandgap Engineering of Organic Semiconductors for Highly Efficient Photocatalytic Water Splitting

“…According to the EA (Table 1) of FAT samples, the oxygen content increases and the nitrogen content declines as more formic acid is added in the precursor, corresponding to the gradual substitution of NH groups with oxygen in the polymer. Such spatial separation might possibly arise from a change in the electrostatic potential of the O-containing cells due to the presence of polar covalent bonds, as shown in previous literature, [57,58] although our modeling could not find solid evidence due to the complexity of the problem and the polymeric nature of the system. Such spatial separation might possibly arise from a change in the electrostatic potential of the O-containing cells due to the presence of polar covalent bonds, as shown in previous literature, [57,58] although our modeling could not find solid evidence due to the complexity of the problem and the polymeric nature of the system.…”

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

“…[9,10] Doping N or P atoms was revealed to be effective in enhancing the activity of graphene in photocatalytic hydrogen evolution. [7,[16][17][18][19] Meanwhile, some experimental reports focused on how to modulate the electronic structure of graphene based materials through introduction of chemical impurities and/or creation of defects, and consequently to synthesize these nanomaterials with desired physical and chemical properties for any targeted applications. Some previous studies have found phosphorene and the MoS 2 monolayer that have desirable optoelectronic properties of ideal band gap, high carrier mobility, and strong visible light absorption, [6,[14][15][16] have relatively poor stability when exposed to the ambient environment containing oxygen and moisture, which has been well discussed.…”

“…Similar to phosphorene and the MoS 2 , [17,18] the BC 2 N monolayer may be environmentally instable induced by its interaction with oxygen and water molecules in air, which is a potential barrier to the further application and manufacture of these 2D materials. In view of this, the stabilities of the BC 2 N monolayers in real environment were performed by AIMD simulation with added oxygen and water molecules in the vacuum space of superlattice.…”

Black Phosphorus‐Based Compound with Few Layers for Photocatalytic Water Oxidation

“…Herein the use of BP coupled with a reductive hydroxide, Ni(OH) 2 , is reported for the first time. 105 cm 2 /V/s, [11][12][13][14][15][16][17][18][19][20] wide range of thickness-dependent direct bandgap of range of 0.3 to 2.0 eV and strong optical absorption near infrared region. The obtained PÀNi(OH) 2 samples present the steady and efficient photocatalytic water splitting for O 2 generation.…”

“…105 cm 2 /V/s, [11][12][13][14][15][16][17][18][19][20] wide range of thickness-dependent direct bandgap of range of 0.3 to 2.0 eV and strong optical absorption near infrared region. 105 cm 2 /V/s, [11][12][13][14][15][16][17][18][19][20] wide range of thickness-dependent direct bandgap of range of 0.3 to 2.0 eV and strong optical absorption near infrared region.…”