Note: Times Cited: 875 Reference EPFL-ARTICLE-206025doi:10.1021/cr0501846View record in Web of Science URL: ://WOS:000249839900009 Record created on 2015-03-03, modified on 2017-05-12

Complex Hydrides for Hydrogen Storage

Photoreduction of CO2 into sustainable and green solar fuels is generally believed to be an appealing solution to simultaneously overcome both environmental problems and energy crisis. The low selectivity of challenging multi-electron CO2 photoreduction reactions makes it one of the holy grails in heterogeneous photocatalysis. This Review highlights the important roles of cocatalysts in selective photocatalytic CO2 reduction into solar fuels using semiconductor catalysts. A special emphasis in this review is placed on the key role, design considerations and modification strategies of cocatalysts for CO2 photoreduction. Various cocatalysts, such as the biomimetic, metal-based, metal-free, and multifunctional ones, and their selectivity for CO2 photoreduction are summarized and discussed, along with the recent advances in this area. This Review provides useful information for the design of highly selective cocatalysts for photo(electro)reduction and electroreduction of CO2 and complements the existing reviews on various semiconductor photocatalysts.

Cocatalysts for Selective Photoreduction of CO2 into Solar Fuels.

Surface modification and enhanced photocatalytic CO2 reduction performance of TiO2: a review

In recent years, metal-organic frameworks (MOFs) have been regarded as one of the most important classes of materials The combination of various metal clusters and ligands, arranged in a vast array of geometries has led to an ever-expanding MOF family Each year, new and novel MOF structures are discovered The structural diversity present in MOFs has significantly expanded the application of these new materials MOFs show great potential for a variety of applications, including but not limited to: gas storage and separation, catalysis, biomedicine delivery, and chemical sensing This review intends to offer a short summary of some of the most important topics and recent development in MOFs The scope of this review shall cover the fundamental aspects concerning the design and synthesis of MOFs and range to the practical applications regarding their stability and derivative structures Emerging trends of MOF development will also be discussed These trends shall include multicomponent MOFs, defect development in MOFs, and MOF composites The ever important structure-property-application relationship for MOFs will also be investigated Overall, this review provides insight into both existing structures and emerging aspects of MOFs

From fundamentals to applications: a toolbox for robust and multifunctional MOF materials.

Adsorption isotherm models: Classification, physical meaning, application and solving method

Memristor, which had been predicted a long time ago (Chua, L. O. IEEE Trans. Circuit Theory 1971, 18, 507), was recently invented (Strukov, D. B.; et al. Nature 2008, 453, 80). The introduction of a memristor is expected to open a new era for nonvolatile memory storage, neuromorphic computing, digital logic, and analog circuit. Furthermore, several breakthroughs were made for memristive phenomena and transistors with single-layer MoS2 (Sangwan, V. K.; et al. Nat. Nanotechnol. 2015, 10, 403. van der Zande, A. M.; et al. Nat. Mater. 2013, 12, 554. Liu, H.; et al. ACS Nano 2014, 8, 1031. Bessonov, A. A.; et al. Nat. Mater. 2015, 14, 199. Yuan, J.; et al. Nat. Nanotechnol. 2015, 10, 389). Herein, we demonstrate that 2H phase of bulk MoS2 possessed an ohmic feature, whereas 1T phase of exfoliated MoS2 nanosheets exhibited a unique memristive behavior due to voltage-dependent resistance change. Furthermore, an ideal odd-symmetric memristor with odd-symmetric I–V characteristics was successfully fabricated by th...

Memristive Behavior and Ideal Memristor of 1T Phase MoS2 Nanosheets

The large energy requirement of CO2 reforming of methane (CRM) has obstructed its application. Solar energy is a solution for the issue. Different from efficient photocatalytic splitting of water, photocatalysis for CRM exhibits a very low efficiency and employs only ultraviolet (UV) light. This letter reports an efficient visible-light photocatalytic CRM by combining Pt/black TiO2 catalyst with light-diffuse-reflection-surface. Under visible light illumination by filtering UV light from AM 1.5G sunlight, H2 and CO yields reached 71 and 158 mmol/h/gcat, with a quantum efficiency of 32.3% at 550 °C, and 129 and 370 mmol/h/gcat, with a quantum efficiency of 57.8% at 650 °C. Those yields are 3 orders of magnitude larger than the reported values.

Efficient Visible Light Photocatalytic CO2 Reforming of CH4

Zn(2-methylimidazole)2 (ZIF-8), as one of the most important metal-organic framework (MOF) molecules, is a promising candidate for drug delivery due to its low-density structure, high surface area, and tunable frameworks. However, ZIF-8 exhibits a high cytotoxicity associated with its external hydrophobic surface, which significantly restricts its application in drug delivery and other biomedical applications. Commonly used chemical functionalization methods would convert the hydrophobic surface of ZIF-8 to hydrophilic, but the generated functional groups on its internal surface may reduce its pore sizes or even block its pores. Herein, a surface defection strategy was applied on the external surface of ZIF-8 to enhance its hydrophilicity without reducing or blocking the internal pores. In this approach, mechanical ball-milling was used to incur defects on the external surface of ZIF-8, leading to unsaturated Zn-sites and N-sites which subsequently bound H2O molecules in an aqueous environment. Furthermore, hydroxyurea delivery and cell cytotoxicity of ZIF-8 with and without the external surface treatment were evaluated. It was found that 5-min ball milling changed the hydrophobic-hydrophilic balance of ZIF-8, resulting in significantly higher cell viability without compromising its hydroxyurea loading and release capacity. Such a simple mechanical ball-milling followed by water-treatment provides a general technique for surface-modification of other MOF molecules, which will undoubtedly magnify their biomedical applications.

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Surface defection reduces cytotoxicity of Zn(2-methylimidazole)2 (ZIF-8) without compromising its drug delivery capacity

The 1T phase of MoS2 is attracting much attention due to its metallic property and potential applications for supercapacitors, photothermal agents, and memristors. However, because the 1T phase is metastable, it can easily be transferred to the stable 2H phase by heating. In this work, it is the first time we observe the mechanically-induced reverse phase transformation (from stable 2H to metastable 1T) for MoS2 by HAADF-STEM images. Furthermore, XPS revealed that the content of the 1T phase increased with increasing mechanical ball-milling time. Furthermore, the mechanically generated 1T MoS2 exhibited memristive behavior.

Mechanically-induced reverse phase transformation of MoS2 from stable 2H to metastable 1T and its memristive behavior

It is generally recognized that H2O adsorption on a porous material would inhibit H2 adsorption. However, this paper reports that stable H2O-functionalized zeolitic Zn(2-methylimidazole)2 framework (ZIF-8), which was obtained by the simple water treatment of ZIF-8 at ambient temperature, can increase its H2 adsorption heat from 5.2 to 10.1 kJ/mol. As a result, the reversible H2 capacity at ambient temperature increased by 77%. This indicates that H2O functionalization provides a novel approach to enhance ambient-temperature hydrogen storage in ZIF-8 and other metal-organic frameworks.

Peifu Cheng

Papers

Memristive Behavior and Ideal Memristor of 1T Phase MoS2 Nanosheets

Efficient Visible Light Photocatalytic CO2 Reforming of CH4

Surface defection reduces cytotoxicity of Zn(2-methylimidazole)2 (ZIF-8) without compromising its drug delivery capacity

Mechanically-induced reverse phase transformation of MoS2 from stable 2H to metastable 1T and its memristive behavior

H2O-Functionalized Zeolitic Zn(2-methylimidazole)2 Framework (ZIF-8) for H2 Storage