Improving the catalytic activity for hydrogen evolution of monolayered SnSe2(1-x)S2x by mechanical strain

An Infrequent 1D Manganese-Tin Selenide with Bifunctional Catalytic Properties

The optoelectronic, electrocatalytic, and photocatalytic properties of new tin selenides are of great significance for various energy applications. Herein, a facile solvothermal reaction of Sn, Se, and MnCl2 in 1,3-propodiamine (1,3-dap) solution at 150 °C for 7 days was used to achieve a new type of one-dimensional (1D) organic hybrid manganese-tin selenide [Mn2(1,3-dap)4(μ-1,3-dap)Sn2Se6]n (MnSnSe-1), whose 1D framework is built up from the linkage of rare unsaturated binuclear [Mn2(1,3-dap)4(μ-1,3-dap)]2+ cations and dimeric [Sn2Se6]4- anions. The combination of MnSnSe-1 and Ni nanoparticle is first applied for the preparation of a Ni/MnSnSe-1/NF electrode (NF = porous Ni foam) as the efficient electrocatalyst for the hydrogen evolution reaction (HER), indicating excellent HER electrocatalytic property with an overpotential of 117 mV at 10 mA·cm-2 in a neutral medium. Owing to its narrow absorption edge of 1.65 eV, implying prominent harvesting ability in the visible-light region, MnSnSe-1 shows a remarkable photocurrent response and excellent visible-light-driven photocatalytic property for the degradation of methylene blue in aqueous solution.

2D Monolayer Catalysts: Towards Efficient Water Splitting and Green Hydrogen Production

A viable alternative to non-renewable hydrocarbon fuels is hydrogen gas, created using a safe, environmentally friendly process like water splitting. An important role in water-splitting applications is played by the development of two-dimensional (2D) layered transition metal chalcogenides (TMDCs), transition metal carbides (MXenes), graphene-derived 2D layered nanomaterials, phosphorene, and hexagonal boron nitride. Advanced synthesis methods and characterization instruments enabled an effective application for improved electrocatalytic water splitting and sustainable hydrogen production. Enhancing active sites, modifying the phase and electronic structure, adding conductive elements like transition metals, forming heterostructures, altering the defect state, etc., can improve the catalytic activity of 2D stacked hybrid monolayer nanomaterials. The majority of global research and development is focused on finding safer substitutes for petrochemical fuels, and this review summarizes recent advancements in the field of 2D monolayer nanomaterials in water splitting for industrial-scale green hydrogen production and fuel cell applications.

Titanium carbide sheet: metallic 2D structure with intrinsic and high catalytic activity for the hydrogen evolution reaction

Searching for a metallic material that possesses intrinsic and high catalytic activity is interesting for the hydrogen evolution reaction (HER) in the electrochemical reduction of water. In this work, via density functional theory, we identified a promising two-dimensional (2D) catalyst material, namely TiC (1 0 0) sheet, which is composed of two atomic layers. Phonon spectrum calculation shows that all vibrational modes of the TiC (1 0 0) sheet are real. Even at 1200 K, the geometrical structure of TiC (1 0 0) sheet is still well kept. Interestingly, TiC (1 0 0) sheet is metallic, which means that TiC (1 0 0) sheet can possess high conductivity. Moreover, the Gibbs free energy ([Formula: see text]) of hydrogen on TiC (1 0 0) sheet at a low coverage is about 0.13 eV, which can be further optimized to an ideal value of 0 eV by introducing a strain. Besides, the effect of thickness on its catalytic activity is also assessed. We observed that TiC (1 0 0) sheet with a large thickness is also metallic. Calculated values of [Formula: see text] for four-layered and six-layered TiC (1 0 0) sheets at a moderate coverage can be about  -0.06 and  -0.04 eV, respectively. Our results highlight a new promising 2D catalyst material for the HER in the electrochemical reduction of water.