Semiconducting quantum dots (QDs) engineering is considered as an effective approach to improve the light-harvesting ability of the devices for solar energy converting. Current routes for the construction of QDs from metal–organic frameworks (MOFs) always retain carbon materials to avoid particle aggregations, which could obstruct light harvesting process. Herein, novel ZnCdS QDs without carbon supporting are rationally designed and fabricated by controlled annealing and a sequential sulfidation and ion-exchange procedure by a zeolitic-imidazolate-framework-8 (ZIF-8)-templated method. Notably, the quantum size could be well controlled, and hence provide the ZnCdS QDs material with suitable band matching, strong electron coupling, uniform and abundant active sites, facilitated photoinduced charge kinetics, and shortened charge diffusion distances, which are vital merits for enhancing photocatalytic performance. The photocatalytic H2 production activity of these QDs can be optimized through adjusting the quantum sizes. Under the irradiation of visible-light and noble-metal cocatalyst-free, an optimal H2 production rate of 3.70 mmol h–1 g–1 could be afford without using noble metal cocatalysts, which is superior to those of bulk ZnCdS and most of the reported ZnCdS-based catalysts. The facile and efficient approach for ZnCdS QDs engineering could be extended to design other kinds of highly efficient metal-sulfide QDs in advanced applications.
A versatile strategy using MOFs as precursors to encapsulate ultrasmall non-noble metal-oxides nanoparticles in the mesopores of KIT-6 is developed.
in a variety of applications including battery materials, [6][7][8] sensors, [9,10] separation engineering, [11,12] and especially heterogeneous catalysis. [13][14][15][16] Since the first report of 3DOM material in 1998 by using polystyrene as template, [17] a variety of macroporous materials have been synthesized with diverse compositions such as metals, [5,18,19] porous carbons, [20,21] metal oxides, [7,22] and metal chalcogenides. [23] In particular, assembling or incorporating other functional species into these 3DOM materials has also opened up another novel avenue to design multifunctional 3DOM materials with the desired properties for a special application. [14,24] Metal-organic frameworks (MOFs) are a new class of crystalline porous materials connected by coordination bonds between metal ions/clusters and organic ligands, which possess a large number of unique properties such as large specific surface area, high porosity, and tunable structure as compared with other conventional porous materials. [25][26][27][28] These unique properties endow MOFs tremendous potentials in a wide range of areas such as heterogeneous catalysis, [29][30][31][32][33][34][35][36][37][38][39][40][41] drug delivery, [42][43][44] optics, [45][46][47] gas storage, [48][49][50] adsorptive separation, [51][52][53][54][55] and sensors. [56][57][58] However, although a large number of MOFs with different porous structures can be easily obtained by using various metal ions and organic ligands, [59] their utilizations are still limited for some diffusion-limited applications, because the majority of MOFs reported so far are restricted to the microporous regime that severely restricts the transportation and diffusion of substrates from approaching the active sites inside MOF crystals. [51] Therefore, how to afford microporous MOFs with hierarchical structure to facilitate their mass diffusion has become a hot spot in porous material field. Accordingly, quite a lot of efforts are devoted to exploring new strategies to build the desired MOFs with various multilevel architectures such as hollow capsule, [60][61][62][63] nanofiber, [64] thin film, [65,66] and aerogel [67] by optimizing coordination conditions and adopting suitable templates. In this regard, our group recently has also successfully fabricated a new kind of ZIF-8 single crystals with highly oriented and ordered macroporous system via a double solventassisted nanocasting strategy. We confirm that the improved mass diffusion property of such 3DOM framework can endow Metal-organic frameworks (MOFs) and related derivatives have attracted significant research attention due to their potential applications in a variety of fields. However, it remains challenging to fabricate MOF-based composites into multidimensional structures, especially to endow them with ordered structures. Here, a facile strategy is developed for the preparation of Pt@ zeolitic imidazolate frameworks (ZIF)-8/SiO 2 composite with 3D-ordered macroporous (3DOM) structure (denoted as 3DOM-Pt@ZIF-8/SiO 2 ) by the in ...
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