Heterogeneous Catalysts. Группа авторов
978‐3‐527‐81356‐8
ePub ISBN: 978‐3‐527‐81358‐2
oBook ISBN: 978‐3‐527‐81359‐9
Preface
Heterogeneous catalyst to a chemical reaction is akin to a microscope to microbiology or a sail to a yacht. It is a necessary tool that helps to speed up reactions and at the same time steers the reactions in such a way that maximum selectivity of the desirable product can be attained. In that sense, heterogeneous catalysts will always be relevant as far as chemical reactions are of interest, whether at large industrial scales (e.g. commodity chemicals, petrochemical refineries), small scales (e.g. devices with catalytic functions such as automobile catalytic converters), or even microscales (e.g. microfluidic devices, catalytic nanomachines). The dedication of scientists and engineers working in the field of heterogeneous catalysis throughout the twentieth century was instrumental in solving of some of the most important problems facing humanity, including the nitrogen food chain issue (the so‐called Nitrogen problem), production of high‐quality automobile fuels (e.g. gasoline and diesel), abatement of noxious airborne pollutants, and the manufacturing of methanol as well as other building block chemicals.
Entering the twenty‐first century, the two immediate and overarching challenges in heterogeneous catalysis are (i) to address the issues related to global warming and climate change and (ii) to align with the United Nations sustainable development goals. Catalytic reactions such as water splitting, reduction of carbon dioxide, waste biomass conversion, removal of emerging aqueous micropollutants, and the abatement of NOx that are focused on enhancing renewable energy security and environmental sustainability will take the center stage against a backdrop of swelling population and increasing urbanization.
In adapting to these grand challenges, new and sophisticated emerging techniques in heterogeneous catalysis are continuously being developed to overcome the various limitations in catalyst design and to understand the mechanism of the molecular reactions occurring on the catalytic surface (information that can feed back to the catalyst design). At the same time, catalysts with different modes of activation are increasingly being appreciated, which besides the conventional thermal catalysts now include electrocatalysts and photocatalysts and their underlying physics. For newcomers entering the field, acquiring such vast amount of knowledge, although essential, can be overwhelming. That is not to mention the tenacity in mastering the basic fundamentals in heterogeneous catalysis, itself a century worth of knowledge, prior to the appreciation of these state‐of‐the‐art advancements. With this in hindsight, the book is geared toward attracting and assisting beginners who wish for a head start and quick overview on some of the most important emerging tools for catalyst design, techniques for operando/in situ characterization and ab initio computation, as well as a glimpse of the advancements in heterogeneous catalysis toward some of the grand challenges. Undergraduates with some prior exposure to reaction engineering/heterogeneous catalysis and analytical chemistry/spectroscopy or early postgraduates pursuing research on heterogeneous catalysis but only with some primitive background of the field shall find the book useful. Because the aim is to bridge the gap between amateur readers and expert knowledge, each chapter provides a brief description of the required basic fundamentals that lead to the appreciation of state‐of‐the‐art advancements.
It should be mentioned that the Contributors of the different chapters in the book are themselves among the most promising Emerging and Pioneering Researchers in the field of heterogeneous catalysis. We capitalized on that point in our book design to allow each Contributor to articulate the advancement of his/her own technique in a semitutorial manner that can be appreciated by the target readers. We strive to preserve a delicate balance between readability and articulating the complexity of the advanced techniques. In that sense, we present the content in a less mathematical (in a semiquantitative form, as much as we could) but comprehensible setting as the first step to inculcate interest and inspiration among beginners. With some patience, self‐learning is highly possible, following which readers should have the ability to pursue more quantitative references of specific techniques. With the heightened expectation of “cross skills” among the new generation of catalyst researchers, this book shall come in handy for readers to gain appreciation on some of the most advanced techniques before deciding to specialize in some of them. In fact, we hope that the book would serve as a platform to inspire readers to potentially develop their own original or hybrid techniques in a wider effort to tackling the grand challenges using heterogeneous catalysts.
Finally, we take the opportunity to thank Emerging and Pioneering Researchers who have contributed to this book, its vision and purpose. It has been a massive effort that took us more than three years to put together this book, and we thank the Contributors for their patience.
Wey Yang Teoh
University of Malaya, Malaysia
23 November 2020
Atsushi Urakawa
Delft University of Technology, The Netherlands
23 November 2020
Yun Hau Ng
City University of Hong Kong, S.A.R.
23 November 2020
Patrick Sit
City University of Hong Kong, S.A.R.
23 November 2020
1 Evolution of Catalysts Design and Synthesis: From Bulk Metal Catalysts to Fine Wires and Gauzes, and that to Nanoparticle Deposits, Metal Clusters, and Single Atoms
Wey Yang Teoh1,2
1 University of Malaya, Centre for Separation Science and Technology, Department of Chemical Engineering, 50603 Kuala Lumpur, Malaysia
2 The University of New South Wales, School of Chemical Engineering, Sydney 2052, Australia
1.1 The Cradle of Modern Heterogeneous Catalysts
The modern discovery of heterogeneous catalysts stretches as far back as 1800 when Joseph Priestley and Martinus van Marum reported the dehydrogenation of alcohol over a heated metal catalyst, although not too much was thought about the role of the metal catalyst at that time except as a heating source. Then in 1813, Louis Jacques Thénard of École Polytechnique in Paris discovered the decomposition of ammonia to nitrogen and hydrogen over “red‐hot metals” and recognized that the phenomenon was due to some catalytic reaction [1, 2]. The concept was followed up by Humphry Davy and Michael Faraday at the Royal Institution of London who, in 1817, reported the flameless catalytic combustion of coal gas and air over heated platinum wire producing bright white ignition. Their results were reproducible when using palladium, but not on copper, silver, iron, gold, and zinc [1, 3]. These experiments made clear that there was some form of catalytic role associated with the different metals. The discovery soon became the basis for the invention of the coal mine safety lamp, also known as the Davy lamp – although mysteriously but rather practically, the use of inefficient steel iron rather than platinum gauze became the standard for Davy lamps. At around the same time, Thénard and Pierre Dulong found that the catalytic ammonia decomposition rates decrease in the following order: iron, copper, silver, gold, and platinum, marking the first recognition of the kinetics of different metal catalysts. The importance of catalytic surface area, as we now know to be one of the most important governing factors in heterogeneous catalysis, was discovered by Edmund Davy (cousin to Humphry Davy) at the University College Cork in the 1820s, who found that finely divided platinum could catalyze the oxidation of alcohol as well as the oxidation of hydrogen at room temperature [4].
In 1831, a little‐known