The characterisation of platinum group metals catalysts is commonly carried out by temperature-programmed reduction, the spectrum of which has been used as a “finger-print” of the reducibility of the catalyst. Recent literature suggests that the utility of temperature-programmed reduction can be further enhanced by combining it with other techniques, such as temperature-programmed desorption and thermogravimetry. Temperature-programmed reduction can be used to investigate phenomena such as metal-support interaction and bimetal formation qualitatively, and to assess quantitatively the stoichiometry of the catalytic precursor. It may also be used to assess metal distribution in a composite oxide supported precursar. An overview of the concepts and applications of temperature-programmed reduction is presented here, and a selection of recent reported methodologies and findings on supported platinum group metal catalysts are discussed.

Introduction American Chemical Society National Meetings and Expositions are held twice a year in spring and autumn and constitute the largest gathering of chemical scientists at any point in the conference calendar. This year the 247th meeting (1) was held from 16th–20th March 2014, hosted at the Dallas Convention Centre, Texas, USA. The overarching theme of the conference was Chemistry...

Oxidative destruction of organic compounds in water streams could significantly reduce environmental effects associated with discharging waste. We report the development of a process to oxidise phenol in aqueous solutions, a model for waste stream contaminants, using Fenton’s reactions combined with in situ synthesised hydrogen peroxide (H₂O₂). Bifunctional palladium-iron supported catalysts, where Pd is responsible for H₂O₂ synthesis while Fe ensures the production of reactive oxygen species required for the degradation of phenol to less toxic species is reported. A comparison is made between in situ generated and commercial H₂O₂ and the effect of phenol degradation products on catalyst stability is explored.

Exhaust gas recirculation is a widely used technology on conventional vehicles, primarily for lowering emissions of local pollutants. Here we use chemical models to show that an exhaust-gas recirculation loop can be converted into a heat-recovery system by incorporating a catalytic reformer. The system is predicted to be particularly effective for gasoline-fuelled spark ignition engines. The high temperature and low oxygen-content of the exhaust gas mean that endothermic reactions will predominate, when some of the gasoline is injected into the recirculation loop upstream of the reformer. The output of the reformer will, therefore, have a higher fuel heating value than the gasoline consumed. Chemical efficiency calculations, based on the predicted reformer output at chemical equilibrium, indicate that the direct improvement in fuel economy could be as high as 14%. Initial tests using a rhodium reforming catalyst suggest that much of the heat recovery predicted by the thermodynamic models can be achieved in practice, which together with a reduction in throttling may allow a gasoline spark ignition engine to match the fuel economy of a diesel engine.

The aim of catalytic wet air oxidation is to use air to remove organic contaminants from wastewater through their complete oxidation, without having to vaporise the water. To date, the widespread exploitation of this process has been held back by the low activity of available catalysts, which means that it has to be operated at above-atmospheric pressure in order to keep the water in the liquid phase at the elevated temperatures required to achieve complete oxidation. Here we present an overview of an ongoing study examining the key requirements of both the active phase and the support material in precious metal catalysts for wet air oxidation, using phenol as the model contaminant. The major outcome to date is that the results reveal a synergy between platinum and hydrophobic support materials, which is not apparent when the active phase is ruthenium.

With a design guided by computational fluid dynamics (CFD), additively manufactured from base metals and coated with metal catalysts using cold spray technology or electroplating, catalytic static mixers are used to replace fixed bed columns in continuous flow reactors. We have shown their versatility in gas-liquid hydrogenations and homogeneous transfer hydrogenations and review here their preparation, stability and wider use in catalytic transformations using flow reactors. Additive manufacturing provides complex mixer structures that can be retrofitted to existing reactor geometry and reduces manufacturing costs by removing abrasive blasting steps in the mixer fabrication process. The rough surface profile of the mixers aids with high metallurgical bonding of the catalyst coating, as shown by the low catalyst leaching levels reported here.

The work presented here introduces the topic of plasma catalysis through selected work in scientific literature and commercial applications, as well as identifying some of the key challenges faced when attempting to utilise non-thermal atmospheric plasma catalysis across multidisciplinary boundaries including those of physics, chemistry and electrical engineering. Plasma can be generated by different methods at many energy levels and can initiate chemical reactions; the main challenges are to selectively initiate desirable reactions either within a process stream or at the surface of a material. The material, which may have intrinsic catalytic properties, the nature of the process gas and the geometry of the reactor will influence the products formed. Previous work has shown that the mechanism for plasma-initiated reactions can be different to that occurring from more traditional thermally stimulated reactions, which opens up possibilities of using different catalytic materials to optimise the reaction rate and product speciation. In addition, the influence of a plasma at the surface of a material and the effects that can be introduced will be discussed.

1. Introduction The 14th European Congress on Catalysis (EuropaCat 2019), themed ‘Catalysis without Borders’, was held on the 18th–23rd August 2019 at the Eurogress conference centre in Aachen, Germany. The conference hosted over 1500 participants from academia and industry across the world, with around 400 lectures and 800 posters presented throughout the week. There were six parallel...

Introduction “Solid-State NMR in Zeolite Catalysis” was written by four professors from the Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, who have tremendous expertise in the fields of solid-state nuclear magnetic resonance (solid-state NMR) and heterogeneous catalysis. This book is Volume 103 in the series ‘Lecture Notes in Chemistry’ published by Springer. It...

With the increasing demand for clean hydrogen production, both as a fuel and an indispensable reagent for chemical industries, acidic water electrolysis has attracted considerable attention in academic and industrial research. Iridium is a well-accepted active and corrosion-resistant component of catalysts for oxygen evolution reaction (OER). However, its scarcity demands breakthroughs in catalyst preparation technologies to ensure its most efficient utilisation. This minireview focusses on the wet-chemistry synthetic methods of the most active and (potentially) durable iridium catalysts for acidic OER, selected from the recent publications in the open literature. The catalysts are classified by their synthesis methods, with authors’ opinion on their practicality. The review may also guide the selection of the state-of-the-art iridium catalysts for benchmarking purposes.

Since the early 2010s, less than a handful of studies have been communicated to the hydrogen and fuel cell communities that special care should be adopted, and a systematic approach should be applied, when homogenising catalyst ink slurries using ultrasound in the form of either a laboratory-grade ultrasonic cleaning bath, or an ultrasonic probe (sonifier). In these studies, it was demonstrated that the use of power ultrasound for the homogenisation of catalyst inks can be detrimental if not used appropriately. Unfortunately, and to this day, literature still indicates that ultrasound is still used for the homogenisation of fuel cell and electrolyser catalyst ink slurries and little or even no experimental conditions are given. To what extent is this approach acceptable? This short review paper discusses the importance of using ultrasound adequately to avoid catalyst dissolution and ionomer degradation induced by acoustic cavitation as well as metallic contamination originating from the ultrasonic probe. It also sheds some light on the important aspects and effects of power ultrasound in liquids and surfaces and presents some recommendations on how to use ultrasound adequately for mixing catalyst ink formulations.

The catalytic steam reforming process of natural gas consumes up to approximately 60% of overall energy used in ammonia production. The optimisation of the reforming catalyst performance can significantly improve the operation of the whole ammonia plant. An online model uses actual process parameters to optimise and reconcile the data of primary reforming products with possibility to predict the catalyst performance. The model uses a combination of commercial simulator and open-source code based on scripts and functions in the form of m-files to calculate various physical properties of reacting gases. The optimisation of steady-state flowsheet, based on real-time plant data from the distributed control system (DCS), is essential for the application of the model at the industrial level. The simplicity of the calculation method used by the model provides the fundamental basis for industrial application in the frame of digitalisation initiative. The principal aim of the optimisation procedure is to change the working curve for methane regarding its equilibrium curve as well as methane outlet molar concentration. This is the critical process parameter in reforming catalyst operation. An industrial top fired primary reformer unit based on Kellogg Inc technology design served for the validation of the model. Calculation procedure is used for continuous online evaluation of the most commercially available primary reformer catalysts. Based on the conducted evaluation, the model can indicate possible recommendations which can mitigate marginal performance and prolong reformer catalyst lifetime.

Photoelectrocatalysis offers a way to generate hydrogen and oxygen from water under ambient light. Here, a series of hydrogen evolving photocatalysts based on a ruthenium(II) bipyridyl sensitiser covalently linked to platinum or palladium catalytic centres were adsorbed onto mesoporous nickel oxide and tested for hydrogen evolution in a photoelectrochemical half-cell. The electrolyte buffer was varied and certain catalysts performed better at pH 7 than pH 3 (for example, PC3 with photocurrent density = 8 μA cm^–2), which is encouraging for coupling with an oxygen evolving photoanode in tandem water splitting devices. The molecular catalysts were surprisingly robust when integrated into devices, but the overall performance appears to be limited by rapid recombination at the photocatalyst|NiO interface. Our findings provide further insight towards basic design principles for hydrogen evolving photoelectrochemical systems and guidelines for further development.

Adsorption is a fundamental process which takes place on a catalyst surface before it dissociates, diffuses over the surface and recombines with other adsorbed species to form the final product. Therefore, in theoretical chemistry understanding of the local geometrical and electronic properties of the adsorbed species on the catalyst surface has been a topic of core focus. In this short review we briefly summarise some of the important developments on theoretical studies related to the adsorption properties of transition metal (TM) catalysts on graphene and graphene-related carbon materials. Prior to this, we will present a discussion on various forms of carbon materials used as catalyst supports, which will be followed by a brief discussion of the fundamentals of the density functional theory (DFT).

This massive volume with a most appropriate title will lead the user to say: ‘I read, I understand modern trends, I will apply’. After perusing it, the reader is encouraged to give a quiz to their students or colleagues: what is the largest scale Heck reaction to date? Why is a reaction in water not a fully ‘green’ process? What are the problems of scale up flow reactions? How much...

Introduction Held under the auspices of European Federation of Catalysis Societies (EFCATS) the 10th EuropaCat Congress was held in Glasgow, UK, from 28th August to 2nd September, 2011 (1). EuropaCat is a highly regarded biennial congress which brings together researchers from across Europe and further afield for scientific dissemination in catalysis. EuropaCat X was a truly international...

This review constitutes a detailed but non-exhaustive examination of the directed ortho metallation (DoM)–cross-coupling fusion in its many flavours. Special attention is paid to the application of the concept of the linked reactions and the synthetic utility that it endows, particularly in the case of one-pot reactions that can greatly increase the ease and efficiency of the process. Personal experience of particular issues that can arise from these reactions and examples of their solutions are given, as well as illustrations of the rapid access to complex molecules that the technique encourages.

The aim of this book “Ball Milling towards Green Synthesis” is to highlight the importance of ball milling as a potential route to produce organic materials. The book was published by the Royal Society of Chemistry and edited by Brindaban Ranu and Achim Stolle. In this book, applications, projects, advantages and challenges related to ball milling for specific organic syntheses are...

  Introduction The 7th International Gold Conference takes place every three years and in 2015 was hosted by the Cardiff Catalysis Institute at Cardiff City Hall, UK, from 26th to 29th July. Scientists from all over the world gathered to discuss the latest advances in gold chemistry. Over three days, the conference covered different aspects from homogeneous and heterogeneous catalysis to...

Here we profile an upcoming researcher who has benefitted from Johnson Matthey's support in the past. David Nelson is a newly appointed Chancellor's Fellow and Lecturer at the University of Strathclyde, in Glasgow, UK. His research interests concern the development of useful transition metal catalysed processes for synthesis via a detailed understanding of mechanism, rate and selectivity...