Marcello Marelli

Bio: Marcello Marelli is an academic researcher from National Research Council. The author has contributed to research in topics: Catalysis & Nanoparticle. The author has an hindex of 26, co-authored 87 publications receiving 3430 citations.

Effect of nature and location of defects on bandgap narrowing in black TiO2 nanoparticles.

Abstract: The increasing need for new materials capable of solar fuel generation is central in the development of a green energy economy. In this contribution, we demonstrate that black TiO2 nanoparticles obtained through a one-step reduction/crystallization process exhibit a bandgap of only 1.85 eV, which matches well with visible light absorption. The electronic structure of black TiO2 nanoparticles is determined by the unique crystalline and defective core/disordered shell morphology. We introduce new insights that will be useful for the design of nanostructured photocatalysts for energy applications.

Broadband Hot Electron Collection for Solar Water Splitting with Plasmonic Titanium Nitride

Abstract: The use of hot electrons generated from the decay of surface plasmons is a novel concept that promises to increase the conversion yield in solar energy technologies. Titanium nitride (TiN) is an emerging plasmonic material that offers compatibility with complementary metal-oxide-semiconductor (CMOS) technology, corrosion resistance, as well as mechanical strength and durability, thus outperforming noble metals in terms of cost, mechanical, chemical, and thermal stability. Here, it is shown that plasmonic TiN can inject into TiO2 twice as many hot electrons as Au nanoparticles. TiO2 nanowires decorated with TiN nanoparticles show higher photocurrent enhancement than decorated with Au nanoparticles for photo-electrochemical water splitting. Experimental and theoretical evidence highlight the superior performance of TiN in hot carrier collection due to several factors. First, TiN nanoparticles provide broadband absorption efficiency over the wavelength range 500–1200 nm combined with high field enhancement due to its natural cubic morphology. Second, TiN forms an Ohmic junction with TiO2, thus enabling efficient electron collection compared to Au nanoparticles. Since TiN nanoparticles have strong plasmon resonances in the red, the entire solar spectrum is covered when complemented with Au nanocrystals. These findings show that transition metal nitrides enable plasmonic devices with enhanced performance for solar energy conversion.

α-Fe2O3/NiOOH: An Effective Heterostructure for Photoelectrochemical Water Oxidation

Abstract: The study of the semiconductor/electrocatalyst interface in electrodes for photoelectrochemical water splitting is of paramount importance to obtain enhanced solar-to-fuel efficiency. Here, we take into consideration the multiple effects that a thin layer of photodeposited amorphous Ni-oxyhydroxide (NiOOH) induces on hematite (α-Fe2O3) photoanodes. The reduction of overpotential produced a photocurrent onset potential advance of 150 mV and an increase of photocurrent of about 50% at 1.23 V vs RHE. To give an interpretation to these phenomena, we carried out deep electrochemical investigations by cyclic voltammetry and electrochemical impedance spectroscopy. The effective charge injection into the electrolyte due to the reduction of the charge transfer resistance at the electrode/electrolyte interface was observed and increased along with the amount of deposited NiOOH. The benefits of NiOOH deposition are ascribable to its ability to scavenge holes from hematite surface traps. This effect is mitigated at a...

Pt and Au/TiO2 photocatalysts for methanol reforming: Role of metal nanoparticles in tuning charge trapping properties and photoefficiency

Abstract: Metal-loaded TiO 2 is, by far, one of the most important class of photocatalysts in hydrogen production through photoreforming of organics and water photosplitting. In this study anatase loaded with Au and Pt nanoparticles (Au/TiO 2 and Pt/TiO 2 ) by an impregnation-reduction method was investigated as for morphological, electronic (XPS) and photocatalytic properties in hydrogen production by methanol photoreforming. The electron and hole trapping centers, Ti 3+ and O − , respectively, formed under UV–vis irradiation of the photocatalysts, were studied by in situ electron spin resonance (ESR) spectroscopy. The nature of the loaded metal affected both the H 2 evolution rate and the distribution of the methanol oxidation products. The better performance of Pt/TiO 2 is attributable to the greater ability of Pt with respect to Au to act as electron sink, slowering the recombination of photoproduced electron–hole couples. Direct evidence of this effect was obtained by ESR analysis, showing that the amount of Ti 3+ active sites follows the order TiO 2 > Au/TiO 2 ≫ Pt/TiO 2 , thus confirming easier electron transfer from Ti 3+ to Pt, where the H + reduction to H 2 occurs.

A Pd/C-CeO2 Anode Catalyst for High-Performance Platinum-Free Anion Exchange Membrane Fuel Cells.

Abstract: One of the biggest obstacles to the dissemination of fuel cells is their cost, a large part of which is due to platinum (Pt) electrocatalysts. Complete removal of Pt is a difficult if not impossible task for proton exchange membrane fuel cells (PEM-FCs). The anion exchange membrane fuel cell (AEM-FC) has long been proposed as a solution as non-Pt metals may be employed. Despite this, few examples of Pt-free AEM-FCs have been demonstrated with modest power output. The main obstacle preventing the realization of a high power density Pt-free AEM-FC is sluggish hydrogen oxidation (HOR) kinetics of the anode catalyst. Here we describe a Pt-free AEM-FC that employs a mixed carbon-CeO2 supported palladium (Pd) anode catalyst that exhibits enhanced kinetics for the HOR. AEM-FC tests run on dry H2 and pure air show peak power densities of more than 500 mW cm(-2) .

I and i

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 …

Understanding TiO2 photocatalysis: mechanisms and materials.

Abstract: Jenny Schneider,*,† Masaya Matsuoka,‡ Masato Takeuchi,‡ Jinlong Zhang, Yu Horiuchi,‡ Masakazu Anpo,‡ and Detlef W. Bahnemann*,† †Institut fur Technische Chemie, Leibniz Universitaẗ Hannover, Callinstrasse 3, D-30167 Hannover, Germany ‡Faculty of Engineering, Osaka Prefecture University, 1 Gakuen-cho, Sakai Osaka 599-8531, Japan Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China

Titanium dioxide-based nanomaterials for photocatalytic fuel generations.

Abstract: Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,† †State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China ‡Department of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States

Cu and Cu-Based Nanoparticles: Synthesis and Applications in Catalysis.

Abstract: The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications i...