Anisotropic Janus SiP 2 Monolayer as a Photocatalyst for Water Splitting

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Phosphorene has offered an additional advantage for developing new optoelectronic devices due to its anisotropic and high carrier mobility. However, its instability in air causes a rapid degradation of the performance of the device. Thus, improving the stability of phosphorene while maintaining its original properties has become the key to the development of high-performance electronic devices. Herein, we propose that the formation of two-dimensional (2D) P-rich P–S compounds could achieve this goal. First-principles swarm-structural searches revealed two previously unkonwn P3S and P2S monolayers. The P3S monolayer, consisting of n-bicyclo-P6 units along the armchair direction, exhibits anisotropic and wide band gap characteristics. Interestingly, its carrier mobility reaches 1.11 × 104 cm2 V–1 s–1 and is much higher than in phosphorene. Its electronic band gap and optical absorption coefficients in the ultraviolet region reach 2.71 eV and 105 cm–1, respectively. Additionally, the P3S monolayer has a high structural stability and resistance to air oxidation.

mentioning

confidence: 74%

Wide Band Gap P₃S Monolayer with Anisotropic and Ultrahigh Carrier Mobility

Wang

Tang

Lou

et al. 2021

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“…In the ultraviolet and visible light regions, its absorption coefficients reach 10 5 cm –1 (Figure f), which is much higher than in g-C 3 N 4 and comparable to that of MoS 2 . Moreover, its absorption coefficients are anisotropic, as observed in phosphorene and SiP 2 . We also calculated the absorption spectra of the C 3 S monolayer under biaxial strain (Figure S6).…”

mentioning

confidence: 92%

Anisotropic and High-Mobility C₃S Monolayer as a Photocatalyst for Water Splitting

Tang

Wang

Lou

et al. 2021

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Taking into account the high conductivity and stability of carbon materials, such as graphene, and the strong polar covalent bonding character of main-group compounds, we explore potential 2D materials in the C–S binary system through first-principles structure search calculations. Herein, a hitherto unknown semiconducting C3S monolayer is identified, consisting of well-known n-biphenyl and S atom linked benzenes, exhibiting an obvious direction-dependent atomic arrangement. Thus, it exhibits anisotropic mechanical properties and carrier mobility. Its electron mobility reaches 2.14 × 104 cm2 V–1 s–1 in the b direction, along which n-biphenyl units are arranged, and is much higher than that in the well-used MoS2 monolayer and black phosphorus. Meanwhile, the C3S monolayer has high optical absorption coefficients (105 cm–1), high thermal and dynamical stabilities, and a moderate ability to split water. All these desirable properties make the C3S monolayer a promising candidate for applications in novel optoelectronic devices.

“…Although the band gap and energy band arrangement of the GaSe/InS heterostructure and P-GaSe/InS heterostructure meet the requirements of the photocatalyst, it is necessary to determine whether the band edge position of the heterostructure meets the occurrence of HER and OER. The standard potentials of H + /H 2 ( E H + /H 2 ) and H 2 O/O 2 ( E H 2 O/O 2 ) , with different pH values can be calculated from the standard potentials under acidic conditions at pH = 0 ( E H + /H 2 = −4.44 eV, E H 2 O/O 2 = −5.67 eV), the formula is as follows: …”

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confidence: 99%

P Doping Promotes the Spontaneous Visible-Light-Driven Photocatalytic Water Splitting in Isomorphic Type II GaSe/InS Heterostructure

Zhang

Yin

2021

The development and design of clean and efficient water splitting photocatalysts is important for the current situation of energy shortage and environmental pollution. A new type of isomorphic GaSe/InS heterostructure is constructed, and the optoelectronic properties were studied through first-principles calculations. The results show that GaSe/InS vdW heterostructure is a type II semiconductor with a band gap of 2.09 eV. However, through the analysis of the energy band edge position and Gibbs free energy change of water splitting, it is found that the GaSe/InS heterostructure is difficult to undergo overall water splitting. Therefore, nonmetallic element P doping is considered, the established P-doped GaSe/InS (P-GaSe/InS) heterostructure could maintain the type II band arrangement, and under acidic conditions, P-GaSe/InS heterostructure could spontaneously undergo overall water splitting thermodynamically. Furthermore, the low exciton binding energy of P-GaSe/InS heterostructure highlights better light absorption performance. Therefore, these findings indicate that P-GaSe/InS heterostructure is a promising photocatalyst in overall water splitting.