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Michael Grätzel

Bio: Michael Grätzel is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Dye-sensitized solar cell & Perovskite (structure). The author has an hindex of 248, co-authored 1423 publications receiving 303599 citations. Previous affiliations of Michael Grätzel include University of California, Berkeley & Siemens Energy Sector.


Papers
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Journal ArticleDOI
TL;DR: In this paper , the authors successfully exfoliated both layered and non-layered ultra-thin metal phosphorous trichalcogenides (MPCh3) nanosheets via wet grinding exfoliation (WGE), and systematically investigated the mechanism of MPCh3 as catalysts for CO2 ECR.
Abstract: Two-dimensional (2D) materials catalysts provide an atomic scale view on fascinating arena for understanding the mechanism of electrocatalytic carbon dioxide reduction (CO2 ECR). Here, we successfully exfoliated both layered and nonlayered ultra-thin metal phosphorous trichalcogenides (MPCh3) nanosheets via wet grinding exfoliation (WGE), and systematically investigated the mechanism of MPCh3 as catalysts for CO2 ECR. Unlike the layered CoPS3 and NiPS3 nanosheets, the active Sn atoms tend to be exposed on the surfaces of nonlayered SnPS3 nanosheets. Correspondingly, the nonlayered SnPS3 nanosheets exhibit clearly improved catalytic activity, showing formic acid selectivity up to 31.6% with -7.51 mA cm-2 at -0.65 V vs. RHE. The enhanced catalytic performance can be attributed to the formation of HCOO* via the first proton-electron pair addition on the SnPS3 surface. These results provide a new avenue to understand novel CO2 ECR mechanism of Sn-based and MPCh3-based catalysts.

1 citations

Posted ContentDOI
19 Jun 2020-ChemRxiv
TL;DR: In this paper, the water oxidation reaction kinetics for hematite photoanodes were determined using four different synthetic procedures and optical signals indicative of charge accumulation in mid-gap oxygen vacancy states.
Abstract: Operando spectroelectrochemical analysis is used to determine the water oxidation reaction kinetics for hematite photoanodes prepared using four different synthetic procedures. Whilst these photoanodes exhibit very different current / voltage performance, their underlying water oxidation kinetics are found to be almost invariant. Lower photoanode performance was found to correlate with the observation of optical signals indicative of charge accumulation in mid-gap oxygen vacancy states, indicating these states do not contribute directly to water oxidation.

1 citations

Journal ArticleDOI
01 Oct 2016-Chimia
TL;DR: A chemical system has been identified that could be used to make an autonomous trap with chemo-attractant system that could help reduce vector populations or their interactions with hosts below a critical level.
Abstract: Undoubtedly, reducing vector populations or their interactions with hosts below a critical level is a practical and proven method of disease control. Introduction of insecticide-treated bed nets has significantly reduced malaria in some parts of the world. However, for many reasons, implementation of such strategies is challenging and the protection offered by particular products limited: bed nets are only effective during sleep. Other methods have been launched, but low customer appeal, high cost, low specificity, and lack of sustainability and effectiveness are often reasons for failure. The proposed solution to these problems should also consider safety and environmental impact and be forward-thinking for continued functioning in a rapidly changing local environment. To this end, a chemical system has been identified that could be used to make an autonomous trap with chemo-attractant system.

1 citations

Book ChapterDOI
TL;DR: In this article, the optimum temperature at which C 2 -product yields were maximum was found when the promoter was changed from Li to Cs through group IA alkali metal chlorides.
Abstract: Oxidative dimerization of CH 4 has been studied using Co 3 O 4 catalysts promoted with chlorides of Li, Na, K and Cs. Chemical modification of Co 3 O 4 - LiCl catalyst at the reaction conditions was evidenced by ESR spectroscopy. A decrease in the optimum temperature, at which C 2 - product yields were maximum, was noticed when the promoter was changed from Li to Cs through group IA alkali metal chlorides.

1 citations

Book ChapterDOI
01 Jan 1984
TL;DR: In this article, the authors studied the characteristics of various catalytic systems capable of generating H by water-photolysis, including completely biological sytems where natural electron carriers such as ferredoxin, flavodoxin, cytochrome c3 or NAD reduced by illuminated chloroplasts are coupled to hydrogen3ses, and semibiological systems where photosynthetically reduced natural or synthetic electron relays (e.g. viologens, metatungstate, cobalt complexes, etc.) are coupled with hydrogenase or Pt for H2 production.
Abstract: We have been studying the characteristics of various catalytic systems capable of generating H by water-photolysis. These include (a) completely biological sytems where natural electron carriers such as ferredoxin, flavodoxin, cytochrome c3 or NAD reduced by illuminated chloroplasts are coupled to hydrogen3ses; (b) semibiological systems wherein photosynthetically reduced natural or synthetic electron relays (e.g. viologens, metatungstate, cobalt complexes, etc.) are coupled to hydrogenase or Pt for H2 production and (c) completely artificial systems using semiconductors, (TiO , RuO , CdS, etc.) as photo and redox catalysts for the photogener2ation 2f H2 by coupling to Pt (see Cuendet, Gratzel 1982a, Rao, Hall 1983). At present we are concerned with the stabilisation of the H generating system and also with the optimisation of the electron an2d proton transfer reactions to achieve the maximum light and catalytic conversion efficiencies. With this objective we are studying (a) the effect of various additives to the medium, (b) the effect of entrapment of photosynthetic membranes in polyurethane, and (c) the efficiency of different synthetic relays on the rate and longevity of H evolution reaction.

1 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
24 Oct 1991-Nature
TL;DR: In this article, the authors describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency.
Abstract: THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive at present: generation from existing commercial devices costs about ten times more than conventional methods1. Here we describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency. The device is based on a 10-µm-thick, optically transparent film of titanium dioxide particles a few nanometres in size, coated with a monolayer of a charge-transfer dye to sensitize the film for light harvesting. Because of the high surface area of the semiconductor film and the ideal spectral characteristics of the dye, the device harvests a high proportion of the incident solar energy flux (46%) and shows exceptionally high efficiencies for the conversion of incident photons to electrical current (more than 80%). The overall light-to-electric energy conversion yield is 7.1-7.9% in simulated solar light and 12% in diffuse daylight. The large current densities (greater than 12 mA cm-2) and exceptional stability (sustaining at least five million turnovers without decomposition), as well as the low cost, make practical applications feasible.

26,457 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: The slow pace of hazardous waste remediation at military installations around the world is causing a serious delay in conversion of many of these facilities to civilian uses as discussed by the authors, which is a serious problem.
Abstract: The civilian, commercial, and defense sectors of most advanced industrialized nations are faced with a tremendous set of environmental problems related to the remediation of hazardous wastes, contaminated groundwaters, and the control of toxic air contaminants. For example, the slow pace of hazardous waste remediation at military installations around the world is causing a serious delay in conversion of many of these facilities to civilian uses. Over the last 10 years problems related to hazardous waste remediation have emerged as a high national and international priority.

17,188 citations