close-packed structures with lower surface energy and anisotropy, leading to great challenges in stabilizing and synthesizing 2D noble metal nanomaterials. To this end, a variety of synthetic strategies, such as hard-template-directed synthesis, capping-agent-assisted synthesis, and secondary assembly methods, have been developed for the synthesis of 2D noble metal-based nanostructures. [2] As one of the alternatives, self-assembly from 0D or 1D primary building blocks has been identified as a sophisticated and reliable approach for the generation of 2D noble metal nanostructures. [3] Ultrathin noble metal nanowires with high surface-tovolume ratios and atom utilization efficiency hold promising applications in widespread fields, including catalysis, optics devices, and biomedicine, etc. [4] Rational engineering of 1D nanowires into 2D nanosheets may bring about many novel structural characteristics, including high porosity, large area per unit volume, good flexibility, and an interconnected open pore structure. [5] Therefore, succinct-operated and controllable synthesis of ultrathin free-standing 2D nanosheets with 1D primary building blocks would be of great significance for fundamental scientific interest and technological applications, yet still remains greatly challenging.Herein, for the first time, we present a novel and facile one-pot, simultaneous stepwise self-assembly approach for the synthesis of freestanding porous Pd nanosheets (≈2.5 µm in lateral size and 10 nm in thickness) with the assistance of a functional polymer, poly(diallyldimethylammonium chloride) (PDDA; Figure S1, Supporting Information). Essentially, the obtained porous Pd nanosheets are flexibly knitted by numerous interweaved ultrathin nanowires. Different from the previously reported 2D noble metal nanosheets with smooth surface, [6,7] the obtained Pd nanosheets with large porosity and rough surface are achieved by particle spontaneous attachment and subsequent self-assembly in the one-pot synthesis process. To the best of our knowledge, this is the first report that the construction of 2D sheet-like Pd porous nanostructures through such a simple and efficient approach so far, and the elaborate adoption of eco-friendly PDDA as a structuredirecting agent also plays a crucial role in the formation of the Freestanding ultrathin 2D noble metal nanosheets have drawn enormous attention due to their potential applications in various fields. However, the synthesis of 2D noble metal nanosheets still remains a great challenge due to the lack of an intrinsic driving force for anisotropic growth of 2D structures. Here, a facile one-pot synthesis of ultrathin freestanding porous Pd nanosheets (≈2.5 µm in lateral size and 10 nm in thickness) flexibly knitted by interweaved ultrathin nanowires with the assistance of poly(diallyldimethylammonium chloride) is presented. Nanoparticles attachment and subsequent self-assembly in the synthetic process are responsible for the formation of such intriguing nanostructures. Moreover, finely controlling the p...

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Potassium poly(heptazine imide) (KPHI) exhibiting the dual functionality of photon absorption and photoelectron storage for solar energy conversion is a new class of ionic two-dimensional (2D) carbon nitrides. Rather than...

Electroactive mesoporous organosilica nanocomposites (EMONs) and electroactive mesoporous goldorganosilica nanocomposites (EMGONs) were successfully prepared in this work and were applied in ascorbic acid (AA) sensing. EMONs were synthesized by using an aniline pentamer (AP) as an electroactive segment which controlled the redox ability and influenced the degree of sensitivity of the nanocomposites towards AA. EMGONs were successfully prepared by a one-pot synthesis in HAuCl 4 aqueous solution with different concentrations. Gold nanoparticles (AuNPs) were selectively reduced on an AP segment in an EMON matrix, which acted as a reductant as well as providing a large surface area to absorb and react with chloroaurate anions (AuCl 4 À ). The gold particle size can be controlled by varying the concentration of HAuCl 4 (aq.), and distributed AuNPs with controllable size were fabricated for the EMGONs. A sensor constructed from an EMGON-modified carbon-paste electrode (CPE) demonstrated 21-fold and 6.3-fold higher electrocatalytic activity towards the oxidation of AA compared to those constructed using a bare CPE and EMON-modified CPE, respectively. The high surface area of the EMGON-modified CPE exhibited a good electrochemical response towards AA at a low oxidative potential with good stability and sensitivity and a wide linear analytical detection range.

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A series of amphiphilic poly(amidoamine) dendrimers (PAMAM, G2-G5) composed of a hydrophilic core and a hydrophobic shell of aniline pentamer (AP) were synthesized and characterized. The modified dendrimers self-assembled to vesicular aggregates in water with the critical aggregation concentration (CAC) decreased in the order of G2 > G3 > G4 > G5. It was found that the modified dendrimers self-organized into spherical aggregates with a bilayer vesicular structures and that the dendrimers in higher generation have more order structure, which may be attributed to the crystallization induced by the compacted effect of AP segments. In addition, larger spherical vesicles were observed under acidic and alkaline conditions, as compared with sizes of aggregates in neutral medium. At low pH, the tertiary amine groups of PAMAM-AP were transformed to ammonium salts; the polarons were formed from AP units by doping with strong acids, thereby leading to the stability of vesicular aggregates being better than that in double distilled water. Nevertheless, in high pH environment, the deprotonation of PAMAM-AP caused the enhancement of π-π interactions, resulting in generation of twins or multilayered vesicles.