Platinum (Pt) is the state-of-the-art catalyst for oxygen reduction reaction (ORR), but its high cost and scarcity limit its large-scale use. However, if the usage of Pt reduces to a sufficiently low level, this critical barrier may be overcome. Atomically dispersed metal catalysts with high activity and high atom efficiency have the possibility to achieve this goal. Herein, we report a locally distributed atomic Pt-Co nitrogen-carbon-based catalyst (denoted as A-CoPt-NC) with high activity and robust durability for ORR (267 times higher than commercial Pt/C in mass activity). The A-CoPt-NC shows a high selectivity for the 4e pathway in ORR, differing from the reported 2e pathway characteristic of atomic Pt catalysts. Density functional theory calculations suggest that this high activity originates from the synergistic effect of atomic Pt-Co located on a defected C/N graphene surface. The mechanism is thought to arise from asymmetry in the electron distribution around the Pt/Co metal centers, as well as the metal atoms' coordination with local environments on the carbon surface. This coordination results from N8V4 vacancies (where N8 represents the number of nitrogen atoms and V4 indicates the number of vacant carbon atoms) within the carbon shell, which enhances the oxygen reduction reaction via the so-called synergistic effect.

In this Account we describe the hydrothermal synthesis of some new materials including microporous crystals, ionic conductors, complex oxides and fluorides, low-dimensional aluminophosphates, inorganic-organic hybrid materials, and particularly condensed materials such as diamond and inorganic helical chains. Hydrothermal synthesis in biology and environment sciences is also introduced. The increasing interest in hydrothemal synthesis derives from its advantages in terms of high reactivity of reactants, easy control of solution or interface reactions, formation of metastable and unique condensed phases, less air pollution, and low energy consumption.

As a new family of adsorbent materials, porous metal-organic frameworks (MOFs) have attracted enormous attention over the past decade.[1] Having a large surface area, [2] tunable pore size and shape, [3] adjustable composition and functionalizable pore surface, [4] MOFs show unique advantages and promises for potential applications in adsorption-based storage and separation technologies for small gas molecules such as H 2 , CO 2 , and CH 4 . [1b,d, 5] CO 2 capture from flue gases is of particular importance in reducing greenhouse gas emissions and in preserving environmental health. A flue gas mixture is composed of nitrogen, carbon dioxide, water vapor, oxygen, and other minor components such as carbon monoxide, nitrogen oxides, and sulfur oxides.[1b, 6] Separation of low-concentration CO 2 (about 10-15 %) from nitrogen-rich streams remains a challenging task at the present time. Adsorption-based CO 2 capture and separation is considered an effective way and may have a real potential if adsorbents with both high CO 2 selectivity and capacity near room temperature (up to 50 8C) and in the lowpressure range can be developed. [7] Recent studies have revealed a number of MOFs that show a high performance in capturing and separating CO 2 from N 2 and other small gases under conditions mimicking power plant flue gas mixtures. [8]

A sol-hydrothermal method has been proposed to prepare uniform and unaggregated nanocrystals of pure anatase and rutile from various acidic mediums. The phase formation, particle sizes, and morphologies varying with different acids and their concentrations at different reaction temperatures and times have been investigated using X-ray diffraction and transmission electron microscopy. The use of HCl and the effect of its concentrations on the formation of rutile phase at different temperatures for various reaction times have been described in detail. The effect of the addition of NaCl salt on particle sizes and rutile fractions has also been studied. In this work, the phase transformation from anatase to rutile in the presence of and the absence of NaCl salt has been considered both in neutral and in acidic mediums. The presence of a trace rutile in starting materials of anatase can show obvious effects on the phase transformation under hydrothermal conditions.

We report here a luminescent metal-organic framework [Zn3(TDPAT)(H2O)3] [TDPAT = 2,4,6-tris(3,5-dicarboxyl phenylamino)-1,3,5-triazine] exhibiting strong luminescence at room temperature, which can serve as the first case of a dual functional luminescent sensor for quantitatively detecting the concentration of nitrobenzene and temperature.

A new strategy toward constructing bifunctionalized MOFs has been developed based on post-synthetic modification of MOFs on organic ligands and coordinatively unsaturated metal sites, respectively. Based on this strategy, an organo-bifunctionalized MOF catalyst has been synthesized for the first time and successfully applied in one-pot tandem reaction.

Uniform nanoparticles of rutile and anatase were prepared, respectively, by a new approach, a microemulsion-mediated method, in which the microemulsion medium was further treated by hydrothermal reaction. Herein, the combined procedure of microemulsion and hydrothermal synthesis to prepare nanoparticles is referred to as a microemulsion-mediated hydrothermal (MMH) method. This MMH method could lead to the formation of crystalline titania powders under much milder reaction conditions than the normally reported microemulsion-mediated methods, in which posttreatment of calcination was necessary. In this work, a kind of solution was formed by dissolving tetrabutyl titanate into hydrochloric acid or nitric acid, and the solution was dispersed in an organic phase for the preparation of the microemulsion medium. The aqueous cores of water/Triton X-100/hexanol/cyclohexane microemulsions were used as constrained microreactors for a controlled growth of titania particles under hydrothermal conditions. The product of hydrothermal synthesis was separated and dried for characterization. The phase components and the morphologies and grain sizes of products were determined by X-ray diffraction (XRD) and by transmission electron microscopy (TEM). The effects of changing the variables of the reaction conditions, such as the use of acid, the concentrations of acid, the reaction temperatures, and/or the reaction times on the phases and morphologies of the titania product are described.

Cell-membrane-coated nanoparticles have emerged as a promising antitumor therapeutic strategy. However, the immunologic mechanism remains elusive, and there are still crucial issues to be addressed including tumor-homing capacity, immune incompatibility, and immunogenicity. Here, we reported a tumor-associated macrophage membrane (TAMM) derived from the primary tumor with unique antigen-homing affinity capacity and immune compatibility. TAMM could deplete the CSF1 secreted by tumor cells in the tumor microenvironment (TME), blocking the interaction between TAM and cancer cells. Especially, after coating TAMM to upconversion nanoparticle with conjugated photosensitizer (NPR@TAMM), NPR@TAMM-mediated photodynamic immunotherapy switched the activation of macrophages from an immunosuppressive M2-like phenotype to a more inflammatory M1-like state, induced immunogenic cell death, and consequently enhanced the antitumor immunity efficiency via activation of antigen-presenting cells to stimulate the production of tumor-specific effector T cells in metastatic tumors. This TAM-membrane-based photodynamic immunotherapy approach offers a new strategy for personalized tumor therapy.