Phase-Controlled Multi-Dimensional-Structure SnS/SnS2/CdS Nanocomposite for Development of Solar-Driven Hydrogen Evolution Photocatalyst.

The quest for water-splitting photocatalysts to generate hydrogen as a clean energy source from two-dimensional (2D) materials has enormous implications for sustainable energy solutions. Photocatalytic water splitting, a major field of interest, is focused on the efficient production of hydrogen from renewable resources such as water using 2D materials. Tin sulfide and tin disulfide, collectively known as SnS and SnS2, respectively, are metal sulfide compounds that have gained attention for their photocatalytic properties. Their unique electronic structures and morphological characteristics make them promising candidates for harnessing solar energy for environmental and energy-related purposes. CdS/SnS/SnS2 photocatalysts with two Sn phases (II and IV) were synthesized using a solvothermal method in this study. CdS was successfully placed on a broad SnS/SnS2 plane after a series of characterizations. We found that it is composited in the same way as a core-shell shape. When the SnS/SnS2 phase ratio was dominated by SnS and the structure was composited with CdS, the degradation efficiency was optimal. This material demonstrated high photocatalytic hydrogenation efficiency as well as efficient photocatalytic removal of Cr(VI) over 120 min. Because of the broad light absorption of CdS, the specific surface area, which is the reaction site, became very large. Second, it served as a transport medium for electron transfer from the conduction band (CB) of the SnS to the CB of the SnS2. Because of the composite, these electrons flowed into the CB of CdS, improving the separation efficiency of the photogenerated carriers even further. This material, which was easily composited, also effectively prevented mineral corrosion, which is a major issue with CdS.

P=O Functionalized Black Phosphorus/1T-WS2 Nanocomposite High Efficiency Hybrid Photocatalyst for Air/Water Pollutant Degradation.

Research on layered two-dimensional (2D) materials is at the forefront of material science. Because 2D materialshave variousplate shapes, there is a great deal of research on the layer-by-layer-type junction structure. In this study, we designed a composite catalyst with a dimension lower than two dimensions and with catalysts that canbe combined so that the band structures can be designed to suit various applications and cover for each other's disadvantages. Among transition metal dichalcogenides, 1T-WS2 can be a promising catalytic material because of its unique electrical properties. Black phosphorus with properly controlled surface oxidation can act as a redox functional group. We synthesized black phosphorus that was properly surface oxidized by oxygen plasma treatment and made a catalyst for water quality improvement through composite with 1T-WS2. This photocatalytic activity was highly efficient such that the reaction rate constant k was 10.31 × 10-2 min-1. In addition, a high-concentration methylene blue solution (20 ppm) was rapidly decomposed after more than 10 cycles and showed photo stability. Designing and fabricating bandgap energy-matching nanocomposite photocatalysts could provide a fundamental direction in solving the future's clean energy problem.

Black phosphorus @ molybdenum disulfide 2D nanocomposite with broad light absorption and high stability for methylene blue decomposition photocatalyst.

Recently, black phosphorus (BP) has become an increasingly popular two-dimensional material with application in many fields. In the field of photocatalyst, the substance is attracted by a wide spectrum and abundant constituents. BP is an attractive material with unique properties owing to its anisotropic structure, which is favorable for catalyst design as a result of bandgap change based on thickness. However, it has proved problematic in the photocatalyst field, due to rapid recombination of electrons and holes. As a result, to overcome this, we used a complex with MoS2 to prevent the recombination of electrons and holes and to have a broad range of optical absorption from visible light to NIR. MoS2 nanoflakes are a two-dimensional (2D) material of the transition metal dichalcogenide family, the advantage of which is that it can be used as a nano-junction between 2D materials. The nanocomposite material of BP and MoS2 shows a remarkable increase in photocatalytic decomposition ability of methylene blue which is an organic dye. It also has many cycles of catalytic ability, which is advantageous in terms of stability. There are expectations that MoS2 @ BP photocatalysts will be widely applied as a non-precious metal photocatalyst with broad light absorption spectra and multi-function photocatalytic materials.

A high-efficiency and stable perovskite solar cell fabricated in ambient air using a polyaniline passivation layer.

Over the past number of years, the power conversion efficiency of perovskite solar cells has remained at 25.5%, reflecting a respectable result for the general incorporation of organometallic trihalide perovskite solar cells. However, perovskite solar cells still suffer from long-term stability issues. Perovskite decomposes upon exposure to moisture, thermal, and UV-A light. Studies related to this context have remained ongoing. Recently, research was mainly conducted on the stability of perovskite against non-radiative recombination. This study improved a critical instability in perovskite solar cells arising from non-radiative recombination and UV-A light using a passivation layer. The passivation layer comprised a polyaniline (PANI) polymer as an interfacial modifier inserted between the active layer and the electron transport layer. Accordingly, the UV-A light did not reach the active layer and confined the Pb2+ ions at PANI passivation layer. This study optimized the perovskite solar cells by controlling the concentration, thickness and drying conditions of the PANI passivation layer. As a result, the efficiency of the perovskite solar cell was achieved 15.1% and showed over 84% maintain in efficiency in the ambient air for one month using the 65 nm PANI passivation layer.