A 3D MOF based on Adamantoid Tetracopper(II) and Aminophosphine Oxide Cages: Structural Features and Magnetic and Catalytic Properties

[Ag4Br6] cluster-based 3D bromoargentate hybrid: crystal structure, optical/photoelectrical performance and theoretical study

The self-assembly of cluster-based halide framework materials has been a matter of great interest but with great challenges. Herein, by exploiting hexamethylenetetramine (Hmta) with Td symmetry as a structural modifier, we successfully constructed and systematically characterized an unusual three-dimensional (3D) hybrid bromoargentate, namely K[NH4][Ag4Br6(Hmta)] (1), bearing a diamond-type [Ag4Br6(Hmta)]n2n- anionic skeleton built up from adamantane-like units of inorganic [Ag4Br6] clusters and organic Hmta ligands. UV-Vis diffuse reflectance analysis showed that the optical bandgap of the title compound was 2.68 eV, indicating a visible-light-responsive semiconductive behavior. More importantly, upon alternate light illumination, the so-designed compound exhibited remarkable photoelectric switching properties, with photocurrent densities (0.38 and 1.10 μA cm-2 for visible and full-spectrum light, respectively) that compete well with and even exceed those of some high-performance metal halide counterparts. Further theoretical calculations, including band structure, density of states, and wave functions, revealed that compound 1 has a unique valence band and conduction band distribution, rendering it with small effective masses (especially the electrons), which may be responsible for its good photoelectricity. Furthermore, in this work, Hirshfeld surface analysis, thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS) studies were performed.

Future Paradigm of 3D Printed Ni-Based Metal Organic Framework Catalysts for Dry Methane Reforming: Techno-economic and Environmental Analyses

Dry reforming of biogas is referred as an attractive path for sustainable H₂ production over decades. Meanwhile, in the Malaysian context, the abundance of palm oil mill effluent (POME) produced annually is deemed as a potential renewable source for renewable energy generation. Conventionally, nickel (Ni) is the most common catalyst used in the industrial-scale dry reforming of methane (DRM) to yield H₂, but it is subject to the drawbacks of sintering and deactivation after a long reaction time at high temperatures (>500 °C). Therefore, this work aims to provide an insight on the feasibility of the application of modified Ni-based catalysts in DRM, specifically in the economic and environmental aspects. From the benchmarking study of various Ni-based catalysts (e.g., bimetallic (Ni-Ce/Al₂O₃), alumina support (Ni/Al₂O₃), protonated titanate nanotube (Ni-HTNT), and unsupported), the Ni-MOF catalyst, notably, had proven its prominence in both economic and environmental aspects on the same basis of 10 tonnes of H₂ production. The MOF-based catalyst not only possessed a better economic performance (net present value 61.86%, 140%, and 563.08% higher than that of Ni-Ce/Al₂O_3, Ni/Al₂O₃, and Ni-HTNT) but also had relatively lower carbon emissions (13.18%, 20.09%, and 75.72% lower than that of Ni/Al₂O₃, Ni-HTNT, and unsupported Ni). This work also accounted for 3D printing technology for the mass production of Ni-MOF catalysts, where the net present value was 2 to 3% higher than that of the conventional production method. Additionally, sensitivity analysis showed that the H₂ price has the greatest impact on the feasibility of DRM as compared to other cost factors.