Transition Metal Dichalcogenides [MX2] in Photocatalytic Water Splitting

The quest for a clean, renewable and sustainable energy future has been highly sought for by the scientific community over the last four decades. Photocatalytic water splitting is a very promising technology to proffer a solution to present day environmental pollution and energy crises by generating hydrogen fuel through a “green route” without environmental pollution. Transition metal dichalcogenides (TMDCs) have outstanding properties which make them show great potential as effective co-catalysts with photocatalytic materials such as TiO2, ZnO and CdS for photocatalytic water splitting. Integration of TMDCs with a photocatalyst such as TiO2 provides novel nanohybrid composite materials with outstanding characteristics. In this review, we present the current state of research in the application of TMDCs in photocatalytic water splitting. Three main aspects which consider their properties, advances in the synthesis routes of layered TMDCs and their composites as well as their photocatalytic performances in the water splitting reaction are discussed. Finally, we raise some challenges and perspectives in their future application as materials for water-splitting photocatalysts

Transition Metal Dichalcogenides [MX₂] in Photocatalytic Water Splitting

The quest for a clean, renewable and sustainable energy future has been highly sought for by the scientific community over the last four decades. Photocatalytic water splitting is a very promising technology to proffer a solution to present day environmental pollution and energy crises by generating hydrogen fuel through a “green route” without environmental pollution. Transition metal dichalcogenides (TMDCs) have outstanding properties which make them show great potential as effective co-catalysts with photocatalytic materials such as TiO2, ZnO and CdS for photocatalytic water splitting. Integration of TMDCs with a photocatalyst such as TiO2 provides novel nanohybrid composite materials with outstanding characteristics. In this review, we present the current state of research in the application of TMDCs in photocatalytic water splitting. Three main aspects which consider their properties, advances in the synthesis routes of layered TMDCs and their composites as well as their photocatalytic performances in the water splitting reaction are discussed. Finally, we raise some challenges and perspectives in their future application as materials for water-splitting photocatalysts

Unraveling the effects of surface functionalization on the catalytic activity of ReSe2 nanostructures towards the hydrogen evolution reaction

Herein, the surface functionalization of ReSe2 nanostructures by surfactants was investigated. This was done to understand how the use of various surfactants affects the catalytic activity of ReSe2 nanostructures towards the hydrogen evolution reaction (HER), and to determine which surfactant would result in maximal exposure of the active edge sites without impeding the catalytic processes of the HER. Oleylamine (OLA), oleic acid (OA), and trioctylphosphine oxide (TOPO) were used as the surfactants. Powder X-ray diffraction confirmed the formation of ReSe2 nanostructures that crystallized in a distorted 1 T phase triclinic system with a P-1 space group. The FTIR, XPS, NMR, and computational studies revealed that the surfactants bind to the surface of the ReSe2 nanostructures through their respective head groups. The ReSe2 nanostructures synthesized using TOPO (ReSe2-TOPO) had the lowest on-set potential, Tafel slope, and overpotential at 10 mA/cm2 at 73 mV, 58 mV/dec, and 171 mV, respectively. The catalytic performance of the nanostructures was significantly affected by their interaction with the surfactants. A high degree of passivation by the surfactant resulted in poor catalytic activity, and a lower degree of passivation resulted in excellent catalytic activity towards the HER

Hierarchical Nanoflowers of Colloidal WS2 and Their Potential Gas Sensing Properties for Room Temperature Detection of Ammonia

A one-step colloidal synthesis of hierarchical nanoflowers of WS2 is reported. The nanoflowers were used to fabricate a chemical sensor for the detection of ammonia vapors at room temperature. The gas sensing performance of the WS2 nanoflowers was measured using an in-house custom-made gas chamber. SEM analysis revealed that the nanoflowers were made up of petals and that the nanoflowers self-assembled to form hierarchical structures. Meanwhile, TEM showed the exposed edges of the petals that make up the nanoflower. A band gap of 1.98 eV confirmed a transition from indirect-to-direct band gap as well as a reduction in the number of layers of the WS2 nanoflowers. The formation of WS2 was confirmed by XPS and XRD with traces of the oxide phase, WO3. XPS analysis also confirmed the successful capping of the nanoflowers. The WS2 nanoflowers exhibited a good response and selectivity for ammonia