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For single‐atom‐layer hydrogen evolution reaction catalysts, enrichment of the 1T‐phase in monolayer molybdenum disulfide is important to achieve ideal metal utilization efficiency and exposure of active surface atoms. Herein, it is discovered that the 1T‐phase degree in monolayer MoS2 can be enhanced through sulfidation of the Pd species deposited on MoS2 (PdxSy/1T‐MoS2). Raman and X‐ray photoelectron spectroscopy reveal that the sulfidation‐assisted phase transition results in considerably greater proportions of 1T‐phase fraction (up to 86%) without using alkali‐metal‐based approaches. Observations of S‐atom displacement/translation at the atomic level contribute to the understanding of the phase transformation of MoS2. The maximized surface atom activation and metal utilization efficiency in PdxSy/1T‐MoS2 lead to unprecedentedly high mass activity (−3444 A mgPd−1) and turnover frequency (1892 s−1), three orders of magnitude higher than those of commercial Pt/C 10 wt% (3.6 A mgPt−1 and 3.6 s−1). The sulfidation‐assisted 1T‐phase enrichment has major implications for the designs of efficient electrocatalysts through MoS2 phase engineering. [ABSTRACT FROM AUTHOR]

Developing sensing approaches that can exploit visible light for the detection of low-concentration hydrogen at room temperatures has become increasingly important for the safe use of hydrogen in many applications. In this study, heterostructures composed of monolayer MoS 2 and Pd nanoclusters (Pd/MoS 2 ) acting as photo- and hydrogen-sensitizers are successfully fabricated in a facile and scalable manner. The uniform deposition of morphologically isotropic Pd nanoclusters (11.5 ± 2.2 nm) on monolayer MoS 2 produces a plethora of active heterojunctions, effectively suppressing charge carrier recombination under light illumination. The dual photo- and hydrogen-sensitizing functionality of Pd/MoS 2 can enable its use as an active sensing layer in optoelectronic hydrogen sensors. Gas-sensing examinations reveal that the sensing performance of Pd/MoS 2 is enhanced three-fold under visible light illumination (17% for 140 ppm of H 2 ) in comparison with dark light (5% for 140 ppm of H 2 ). Photoactivation is also found to enable excellent sensing reversibility and reproducibility in the obtained sensor. As a proof-of-concept, the integration of Pd nanoclusters and monolayer MoS 2 can open a new avenue for light-induced hydrogen gas sensing at room temperature.

Effective incorporation of multiple types of ligands in a given coordination structure provides structural complexity and functional diversity to the resultant coordination-driven assembly. One of the most widely used synthetic approaches is the utilization of the molecular symmetry principle to combine multiple ligands and specific metallic centers in a preferred manner. The variation of metal ions can be helpful to understand the importance of symmetry for the generation of structurally hierarchical supramolecular platforms. We describe the synthesis and characterization of isostructural supramolecular helicates, [M 8 (PDA) 6 (AIP) 3 (DMF) 6-x (H 2 O) x ] (M=Ni (1), Co (2), and Mn (3); PDA=2,6-pyridinedicarboxylate; AIP=5-aminoisophthalate; x=0 for 1, and x=4 for 2 and 3). The effect of metal variation on the formation of supramolecular helicates and their solid-state crystal packing are discussed. Despite the disparity in the ionic radii and distinct coordination-geometry preferences of Co 2+ , Ni 2+ , and Mn 2+ , all metal centers engaged in the assembly with the heteroleptic ligands in the same manner to form isostructural supramolecular helicates., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Metallosupramolecule-based polymeric platforms with high degrees of hierarchy and tailorable functionalities are of great interests because of their unique morphologies and potential applications. Herein, the controllable synthesis of a highly-ordered polymeric structure, {[M,P-Co 8 (PDA) 6 (HIP) 3 (DMF) 5 (H 2 O)] 3 -[Co(DMF)(H 2 O) 2 ]} (1) (PDA=2,6-pyridinedicarboxylate, HIP=5-hydroxyisophthalate, DMF=dimethylformamide) with unique topology is reported. The solid-state structure of 1 reveals that it is alternately and periodically assembled from racemic supramolecular monomers to form a zigzag-shaped polymeric strand. Discrete racemic supramolecules (2) with topologies similar to those of monomeric species of 1 are also controllably synthesized in a separate reaction. Formation of intermolecular hydrogen bonds between supramolecules associated with hydroxyl groups of HIPs are critical for the unique solid-state packing geometries of 1 and 2., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nano- (or micro-scale) metal-organic frameworks (NMOFs), also known as coordination polymer particles (CPPs), have received much attention because of their structural diversities and tunable properties. Besides the direct use, NMOFs can be alternatively used as sacrificial templates/precursors for the preparation of a wide range of hybrid inorganic nanomaterials in straightforward and controllable manners. Distinct advantages of using NMOF templates are correlated to their structural and functional tailorability at molecular levels that is rarely acquired in any other conventional template/precursor. In addition, NMOF-derived inorganic nanomaterials with distinct chemical and physical properties are inferred to dramatically expand the scope of their utilization in many fields. In this review, we aim to provide readers with a comprehensive summary of recent progress in terms of synthetic approaches for the production of diverse inorganic hybrid nanostructures from as-synthesized NMOFs and their promising applications., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)