Bulk gold is chemically inert and is generally regarded as a poor catalyst. However, when gold is in very small particles with diameters below 10 nm and is deposited on metal oxides or activated carbon, it becomes surprisingly active, especially at low temperatures, for many reactions such as CO oxidation and propylene epoxidation. The catalytic performance of Au is defined by three major factors: contact structure, support selection, and particle size. The role of the perimeter interfaces of Au particles as the sites for reactions is discussed as well as the change in chemical reactivity of Au clusters composed of fewer than 300 atoms.

When Gold Is Not Noble: Catalysis by Nanoparticles

Carbon nanotubes (CNTs), due to their unique electronic and extraordinary mechanical properties, have been receiving much attention for a wide variety of applications. Recently, plasma enhanced chemical vapour deposition (PECVD) has emerged as a key growth technique to produce vertically-aligned nanotubes. This paper reviews various plasma sources currently used in CNT growth, catalyst preparation and growth results. Since the technology is in its early stages, there is a general lack of understanding of growth mechanisms, the role of the plasma itself, and the identity of key species responsible for growth. This review is aimed at the low temperature plasma research community that has successfully addressed such issues, through plasma and surface diagnostics and modelling, in semiconductor processing and diamond thin film growth.

https://iopscience.iop.org/article/10.1088/0963-0252/12/2/312/pdf

Carbon nanotube growth by PECVD: a review

Gold can be deposited as nanoparticles on a variety of support materials by coprecipitation or deposition-precipitation of Au(OH)3, grafting of organo-gold complexes such as dimethyl-Au(III)-acetylacetonate, mixing of colloidal Au particles, and vacuum deposition. Owing to the moderate adsorption of at least one of reactants (for example, CO) on the edges and corners of Au nanoparticles and to the activation of the counter reactant (for example, O2) at the perimeter interface with the supports, supported Au nanoparticle catalysts exhibit unique and practically useful catalytic properties at relatively low temperature below 473K. They have already been commercially used for deodorizers in rest rooms in Japan and will find growing applications in indoor air quality control, pollutant emission control, production of hydrogen energy carrier, and innovations in chemical processes. Cluster science of Au may also open an exciting area of research showing some magic numbers for dramatic changes in reactivity.

/pdf/gold-as-a-novel-catalyst-in-the-21st-century-preparation-1nhmkjc9vm.pdf

Gold as a novel catalyst in the 21st century: Preparation, working mechanism and applications

The replacement of current petroleum-based plastics with sustainable alternatives is a crucial but formidable challenge for the modern society. Catalysis presents an enabling tool to facilitate the development of sustainable polymers. This review provides a system-level analysis of sustainable polymers and outlines key criteria with respect to the feedstocks the polymers are derived from, the manner in which the polymers are generated, and the end-of-use options. Specifically, we define sustainable polymers as a class of materials that are derived from renewable feedstocks and exhibit closed-loop life cycles. Among potential candidates, aliphatic polyesters and polycarbonates are promising materials due to their renewable resources and excellent biodegradability. The development of renewable monomers, the versatile synthetic routes to convert these monomers to polyesters and polycarbonate, and the different end-of-use options for these polymers are critically reviewed, with a focus on recent advances in c...

Catalysis as an Enabling Science for Sustainable Polymers

Increasing the stream of recycled plastic necessitates an approach beyond the traditional recycling via melting and re-extrusion. Various chemical recycling processes have great potential to enhance recycling rates. In this Review, a summary of the various chemical recycling routes and assessment via life-cycle analysis is complemented by an extensive list of processes developed by companies active in chemical recycling. We show that each of the currently available processes is applicable for specific plastic waste streams. Thus, only a combination of different technologies can address the plastic waste problem. Research should focus on more realistic, more contaminated and mixed waste streams, while collection and sorting infrastructure will need to be improved, that is, by stricter regulation. This Review aims to inspire both science and innovation for the production of higher value and quality products from plastic recycling suitable for reuse or valorization to create the necessary economic and environmental push for a circular economy.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/anie.201915651

Beyond Mechanical Recycling: Giving New Life to Plastic Waste

Alkyldiarylsulfonium salts of 9, 10,-dithiophenoxyanthracene are useful as photoinitiators in resist compositions, such as epoxy resin formulations, particularly using long wavelength light.

Sulfonium salt photoinitiators

Acid diffusion during postexposure baking is viewed to be a limiting factor in the extension of lithography using chemically amplified resists to formation of nanoscale features. Quantification of thermally activated reaction-diffusion kinetics in these materials is therefore an important step in understanding the extendability of this class of resist systems. Previous investigations have addressed this issue, however there is poor agreement among them, and too few data exist in the literature to allow the systematics of the effect of polymer, photoacid generator, added base or other resist components on the diffusion process to be understood. We describe in this article a combined experimental and modeling protocol that is designed to elucidate the chemistry and physics of the reaction-diffusion process. Because it is physically based, not phenomenological, it provides a means of developing a set of predictive, mutually comparable data that will allow new insights to be developed into the nanoscale behav...

Determination of coupled acid catalysis-diffusion processes in a positive-tone chemically amplified photoresist

We have studied the chemical vapor deposition of copper from 1,5‐cyclooctadiene Cu(I) hexafluoroacetylacetonate, a moderately volatile yellow cystalline solid. It yields pure copper by pyrolytic decomposition at 150–250 °C, produces copper films with near bulk resistivity, and has the advantage of being air stable at room temperature.

Chemical vapor deposition of copper from 1,5‐cyclooctadiene copper(I) hexafluoroacetylacetonate

Essais de plusieurs precurseurs les meilleurs etant Me 2 Au(acac), Me 2 Au(tfac) et Me 2 Au(hfac)

Chemical Vapor Deposition of Gold

The laser‐induced deposition of high‐purity aluminum metal has been achieved by pyrolytic decomposition of trimethylamine aluminum hydride. The chemical structure of the precursor affords a high ambient vapor pressure which results in rapid rates of aluminum film formation. In addition, the precursor is nonpyrophoric, in contrast to other trialkylaluminum precursors. These combined chemical and physical properties make trimethylamine aluminum hydride an ideal precursor for laser‐induced chemical vapor deposition of aluminun films.

Carl E. Larson

Papers

Sulfonium salt photoinitiators

Determination of coupled acid catalysis-diffusion processes in a positive-tone chemically amplified photoresist

Chemical vapor deposition of copper from 1,5‐cyclooctadiene copper(I) hexafluoroacetylacetonate

Chemical Vapor Deposition of Gold

Laser‐induced chemical vapor deposition of aluminum