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Photocatalytic water splitting, a process aimed at hydrogen production, is considered a pivotal clean energy sources to achieve environmental friendliness and high energy efficiency in the future. The crux of achieving this objective lies in the design of stable and efficient catalysts. Herein, we proposed a novel type-II band alignment GaSe/YAlS 3 van der Waals heterostructure with robust stability for photocatalytic water splitting. The intrinsic electric field of YAlS 3 monolayer can break the requirement of band gap (>1.23 eV) in traditional photocatalytic water splitting theory and significantly enhancing the utilization of solar energy. Encouragingly, compared to individual monolayers GaSe or YAlS 3 , the optical absorption coefficients of the GaSe/YAlS 3 heterostructure are significantly improved and the corrected solar-to-hydrogen (STH) efficiency is improved by 406% and 132%, respectively, reaching an impressive 29.73% efficiency. Furthermore, the heterostructure demonstrates exceptional overall water splitting performance across a broad pH range and maintains a consistently high STH efficiency (25.41%∼34.71%) under a wide range biaxial strain (−6%–5%). In addition, the designed GaSe/YAlS 3 heterostructure showcases enhanced absorption of visible as well as partial absorption of infrared light for photocatalytic water splitting. These compelling findings unequivocally establish GaSe/YAlS 3 heterostructure as an excellent and promising candidate for photocatalytic water splitting. [Display omitted] • The GaSe/YAlS 3 heterostructure is a stable type-II van der Waals semiconductor with large intrinsic electric field. • The GaSe/YAlS 3 heterostructure has a high STH efficiency of 29.73% and can be further enhanced by biaxial tensile strain. • The optical absorption intensity of GaSe/YAlS 3 heterostructure has greatly enhanced in infrared and visible light range. • The GaSe/YAlS 3 heterostructure is a promising water-splitting photocatalyst. [ABSTRACT FROM AUTHOR]

Hydrogen production from water photolysis is considered to be one of the main approaches to obtain clean energy in the future. Two-dimensional (2D) materials with intrinsic vertical electric field can break the band gap limitation (>1.23 eV) of photocatalysts in traditional theory, and broaden the spectrum that can be used for photocatalytic water splitting, such as infrared light. Inspired by the ferroelectric phase α- B 2 C 3 (B = Al, Ga, In; C = S, Se, Te), we replaced one of the B atoms with IIIB elements (namely Sc and Y) of the same valency, and successfully predicted 18 kinds of ABC 3 (A = Sc, Y; B = Al, Ga, In; C = S, Se, Te) monolayers with high stability. Encouragingly, 15 predicted ABC 3 monolayers possess direct band gap features in contrast to that of α- B 2 C 3 , which all exhibit indirect band gap feature. Due to the large intrinsic vertical electric field, the ABC 3 monolayers hold great potential for efficient photocatalytic water splitting in acidic and alkaline as well as neutral environments. The rectified solar-to-hydrogen (STH) efficiencies of 14 ABC 3 MLs were larger than 20%. Excitingly, the STH efficiency limits of YGaTe 3 and YInTe 3 even reach 35.97% and 36.94% using the full solar spectrum, which breaks the conventional theoretical efficiency limit. In addition, considerable light absorption and large carrier mobility are confirmed in ABC 3 MLs. These interesting findings render ABC 3 monolayers a strong candidate for future photovoltaic and nanoelectronic applications. [Display omitted] • A new family of two-dimensional semiconductors ABC 3 (A = Sc, Y; B = Al, Ga, In; C = S, Se, Te) has been predicted based on first-principles calculations. • 15 of the 18 ABC 3 monolayers possess direct band gap features in contrast to that of ferroelectric phase α- B 2 C 3. • ABC 3 monolayers exhibit large intrinsic vertical electric fields and hold great potential for photocatalytic water splitting. [ABSTRACT FROM AUTHOR]

Monolayer Ge 2 P 4 S 2 and Ge 2 As 4 S 2 are proposed as a new type of efficient photocatalyst for water splitting, based on first-principles calculations. Monolayer Ge 2 As 4 S 2 exhibits a direct band gap of 1.89 eV (based on HSE06 calculation), while monolayer Ge 2 P 4 S 2 is an indirect gap semiconductor that can turn into direct band gap by applying 3% compressive strain. Moreover, the band edge positions of monolayer Ge 2 P 4 S 2 and Ge 2 As 4 S 2 perfectly cover the redox potentials of water. Remarkably, the Ge 2 P 4 S 2 and Ge 2 As 4 S 2 monolayers possess rather high carrier mobilities (∼103–104 cm2 V−1 s−1), and have moderate optical absorption performance in the range of visible light. In addition, the adsorption and decomposition of water molecules on monolayer Ge 2 P 4 S 2 and Ge 2 As 4 S 2 are explored to illustrate the mechanism of photocatalytic hydrogen formation. These results demonstrate that the monolayer Ge 2 P 4 S 2 and Ge 2 As 4 S 2 hold great potential for photocatalytic water splitting. Image 1 • Monolayer Ge 2 As 4 S 2 and Ge 2 P 4 S 2 show considerable light absorption. • Suitable band gaps and band alignments benefit photolytic water splitting. • Strain can tune the indirect band structure of Ge 2 P 4 S 2 to direct. • High carrier mobilities well separate photogenerated electrons and holes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A two-dimensional semiconductor monolayer PdI 2 has been predicted from its van der Walls bulk material. • PdI 2 monolayer exhibits an extraordinary in-plane negative Poisson ratio (-0.183). • Ultralow lattice thermal conductivity (0.23 ∼ 0.34 Wm-1 K-1) have been revealed in monolayer PdI 2 at room temperature. • The V-shaped crystal structure makes PdI 2 monolayer an excellent platform for alkali ions migration (0.08 eV to 0.152 eV). Using first-principles calculations, we predicted a multifunctional two-dimensional (2D) semiconductor PdI 2 from its van der Walls layered bulk. Monolayer or multilayer PdI 2 obtained by mechanical exfoliation exhibit high stability as freestanding 2D materials. Originating from its special corner-shared quasi-plane crystal structure, an amazing in-plane negative Poisson's ratio in monolayer PdI 2 has been confirmed. The layer dependent electronic and thermal properties have also been discussed in detail. Encouragingly, it has been found that strong phonon scattering which is induced by low symmetry will further reduce the lattice thermal conductivity in monolayer PdI 2 at room temperature. Besides, the monolayer PdI 2 is seen as an excellent platform for alkali ions migration with ultralow diffusion barriers, benefiting from its distinctive V-shaped crystal structure. Considering these interesting findings, we believe the 2D PdI 2 will be a promising candidate for future's low dimensional electron devices. [ABSTRACT FROM AUTHOR]

Background Mutations of the SCN4A gene cause several skeletal muscle channelopathies and overlapping forms of these disorders. However, the variability of the clinical presentation in childhood is confusing and not fully understood among pediatric neurologists. Patients We found three different mutations (p.V445M, p.I693L, and a novel mutation, p.V1149L) in SCN4A but not in the CLCN1 gene. The patient with p.V445M showed the clinical phenotype of sodium channel myotonia, but her clear symptoms did not appear until 11 years of age. Her younger sister and mother, who have the same mutation, displayed marked intrafamilial phenotypic heterogeneity from mild to severe painful myotonia with persistent weakness. The patient with p.I693L exhibited various symptoms that evolved with age, including apneic episodes, tonic muscular contractions during sleep, fluctuating severe episodic myotonia, and finally episodic paralyses. The patient with the novel p.V1149L mutation exhibited episodic paralyses starting at 3 years of age, and myotonic discharges were detected at 11 years of age for the first time. Conclusion The present cohort reveals the complexity, variability, and overlapping nature of the clinical features of skeletal muscle sodium channelopathies. These are basically treatable disorders, so it is essential to consider genetic testing before the full development of a patient's condition. [ABSTRACT FROM AUTHOR]