Catalysis for production of renewable energy

Jinlong Gong

Jinlong Gong studied chemical engineering and received his BS degree from Tianjin University and his PhD degree from the University of Texas at Austin under the guidance of C. B. Mullins. After a stint with Professor George M. Whitesides as a postdoctoral research fellow at Harvard University, he joined the faculty of Tianjin University, where he currently holds a Pei Yang Professorship in chemical engineering. He was a visiting scientist at the Pacific Northwest National Laboratory in 2007. He has served on the editorial boards for several journals including Chemical Society Reviews, Chemical Science, AIChE Journal and Scientific Reports. He has also served as an associate editor for Chemical Engineering Science. He is an elected Fellow of the Royal Society of Chemistry (FRSC). He has published more than 110 papers in peer-refereed journals and been listed as a co-inventor on 30 patents and applications. His research interests in surface science and catalysis include catalytic conversions of green energy, novel utilizations of carbon dioxide, and synthesis and applications of nanostructured materials.

Rafael Luque

Rafael Luque (Ph.D 2005 from Universidad de Cordoba, Spain) has significant experience in biomass and waste valorisation practises to materials, fuels and chemicals as well as nanoscale chemistry. He has also published extensively (>220 publications) in the areas of (nano)materials science, heterogeneous (nano)catalysis, microwave and flow chemistry, biofuels and green chemical methods in synthetic organic chemistry as well as made numerous contributions to book chapters and invited, guest, keynote and plenary lectures in scientific events worldwide. He is also heavily involved in Chemical Education and promoting Science in Developing Countries. Among recent awards, Rafael has received the Marie Curie Prize from Instituto Andaluz de Quimica Fina in Spain (2011), the Green Talents award from the Federal Ministry of Education and Research in Germany (2011), the TR35 Spain from Technology Review and MIT as one of the top 10 young entrepreneurs in Spain (2012) and very recently the RSC Environment, Sustainability and Energy Early Career Award (2013) from the Royal Society of Chemistry, UK. Rafael has also been recently honored as 2013 Distinguished Engineering Fellow and Visiting Professor from CBME at Hong Kong University of Science and Technology in Hong Kong and is currently Chinese Academy of Sciences Visiting Professor at the State Key Laboratory of Electroanalytical Chemistry of the Changchun Institute of Applied Chemistry. Prof. Luque combines his academic duties with his activities as young entrepreneur and co-founder of Green Applied Solutions S.L.U. and more recently as part of Posidonia Oceanica S.L.

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Catalysis is a fundamental pillar of current chemical industry which has allowed a number of significant developments in processes and technologies for the benefit of humankind in recent years. Apart from chemically catalysed processes, recent advances for the production of renewable energy (e.g. biofuels, solar/fuel cells, solar energy, etc.) have been based on catalytic processes using advanced technologies and innovative (nano)materials. This themed issue aims to highlight recent advances and developments in catalytic processes for the production of renewable energies, encompassing areas of knowledge from fuel cells to biofuels, biomass and waste valorisation as well as solar energy and related topics.

Catalyst development is in fact one of the key points in the design of efficient catalytic processes able to maximise the value of starting materials while minimizing waste generation and energy requirements. The state-of-the-art in the design of nanointerfaces for advanced catalytic processes is illustrated by Wang et al. (DOI: 10.1039/C3CS60389J) with an interesting focus on fine control to synthesize complex nanomaterials with well-defined interfaces in view of their potential for nanocatalysis towards renewable energy.

Advancing catalytic processes for biomass valorisation to biofuels, the contribution by Wilson, Lee et al. (DOI: 10.1039/C4CS00189C) also illustrates the potential of catalyst design based on fundamental understanding for the particular production of biodiesel, an important fuel replacement derived from renewable resources, via esterification and transesterification processes.

Continuing with the design of advanced catalysts for biomass valorisation to biofuels, the contribution from Wang et al. (DOI: 10.1039/C3CS60414D) provides an overview of the fundamentals of catalyst design for catalytic fast pyrolysis processes of lignocellulosic materials, with particular emphasis on the chemistries involved in fast pyrolysis as well as bio-oil yields and quality.

The use of biomass, bio-waste and CO₂ derived raw materials as feedstocks for chemicals and biofuels production is reviewed and discussed by Perathoner et al. (DOI: 10.1039/C3CS60396B) with a focus on their sustainable production and the development of catalysts for industrial targets including light alkenes, butadiene as well as HMF and derived products synthesis. Along similar lines, Sels et al. (DOI: 10.1039/C4CS00105B) illustrate the possibilities for butadiene synthesis from biomass-related feedstocks and subsequent applications through a fascinating journey combining old and recent advances in catalytic processes (e.g. reaction conditions, paths and catalyst developments).

Primo and Garcia (DOI: 10.1039/C3CS60394F) further discuss synthesis and applications of zeolites in important refining processes including light naphtha isomerization, olefin alkylation, reforming, cracking and hydrocracking, highlighting their future implications in their co-processing with biofuels for advanced generation transportation fuels.

The development of mesoporosity for the preparation of advanced hierarchical structures is the topic of the contribution by Silvestre-Albero and Garcia-Martinez et al. (DOI: 10.1039/C3CS60435G), in which a wide range of designer mesoporous materials are extensively covered, finding relevant applications in fields as different as biofuels production (liquid and gaseous), solar and fuel cells, thermoelectric devices, photocatalysis, etc.

Different metal and metals oxides have important implications in numerous catalytic reactions for the production of energy. Along these lines, the topic of well-defined supported early transition metal oxides including WO₃ and MoO₃ catalysts in the conversion of small aliphatic alcohols to alkenes, aldehydes/ketones, and ethers is covered by Rousseau et al. (DOI: 10.1039/C3CS60445D). The manuscript provides important insights into detailed theoretical calculations for reaction mechanisms as well as the origin of differences in catalytic activity.

Comparatively, noble metal catalysts have been extensively designed and utilised in dry methane reforming processes as highlighted in the contribution by Spivey et al. (DOI: 10.1039/C3CS60395D) which focuses on the preparation of advanced Rh, Ru, Pt, and Pd metal-containing catalysts for dry (CO₂) reforming of methane towards the production of syngas for various applications.

Weaver et al. (DOI: 10.1039/C3CS60420A) discuss advances in the fundamental understanding of alkane activation on oxide surfaces for the design of new catalysts that efficiently and selectively promote chemical transformations of alkanes, focusing on alkane adsorption and C–H bond activation on PdO(101) surfaces as well as on RuO₂ and IrO₂.

Wang et al. (DOI: 10.1039/C3CS60409H) provides an overview on the utilisation of ionic liquids (ILs) as alternative catalysts, solvents or electrolytes in three broadly interesting energy production processes from renewable resources such as CO₂ conversion to fuels and fuel additives, biomass pretreatment and conversion to biofuels, as well as solar energy and energy storage.

The fundamentals of bioelectrochemical systems (including electrocatalysts, photoelectrocatalysts and bioelectrocatalysts) and their implications in the production of energy are comprehensively covered by Yu et al. (DOI: 10.1039/C3CS60130G) in a review which compares their limitations and influential factors, catalytic performances (efficiency, stability, selectivity, etc.), with some views on future research directions.

The future of metal–air batteries in also discussed in the manuscript by Zhang et al. (DOI: 10.1039/C3CS60248F), with a particular emphasis on fundamentals and recent advances of oxygen catalyst batteries including those containing transition metal oxides, functional carbon materials, metal–nitrogen complexes, transition metal nitrides, conductive polymers and alloys, with future directions and challenges in the field related to such systems as well as Li–air batteries as alternative to Li–ion batteries.

Important contributions in catalyst development related to novel approaches towards artificial photosynthesis and photo-derived technologies for water splitting are also covered in the themed issue. Domen et al. (DOI: 10.1039/C3CS60378D) provide a useful tutorial review on the fundamental aspects of photocatalytic and photoelectrochemical water splitting. They particularly emphasize the importance of molecular control of semiconducting properties as well the construction of p–n junctions to facilitate charge separation and to upgrade the stability of the material under photoexcitation. Qiao et al. (DOI: 10.1039/C3CS60425J) point out that the utilization of co-catalysts could effectively improve catalytic H₂ and O₂ evolution reactions, which remains an under-developed field to date. The authors systematically summarize the role of earth-abundant co-catalysts for water splitting.

The topic of molecular artificial photosynthesis is covered in detail in the tutorial review by Llobet et al. (DOI: 10.1039/C3CS60405E) which aims to provide the fundamentals of light capturing and conversion, water oxidation catalysis, proton and CO₂ reduction catalysis as well as the appropriate combination of these to design advanced catalytic systems for the generation of solar fuels.

In order to provide alternative solutions to key challenges confronted by photoelectrochemical water splitting, Gong et al. (DOI: 10.1039/C3CS60370A) describe the employment of atomic layer deposition for advanced catalyst design and development with important advantages in activity and selectivity as well as important insights into surface reaction mechanisms. Furthermore, Ji et al. (DOI: 10.1039/C3CS60392J) overview recent developments of photoanodes and systems for photoelectrochemical hydrogen production from water and renewable biomass derivatives such as methanol, ethanol, glycerol and sugars.

The contribution from Zaera (DOI: 10.1039/C3CS60374A) discusses the relevance of coupling IR absorption spectroscopy to catalytic systems by providing a comprehensive overview of IR setups, surface characterisation and investigation of specific catalytically active sites, of significant for a better understanding of catalytic processes for energy production.

The contribution by Luque et al. (DOI: 10.1039/C4CS00235K) aims to provide an overview of key advances in the field of lignin depolymerisation, identifying a series of key relevant strategies including hydrotreating, oxidative and biocatalytic technologies to deconstruct lignin into useful value-added aromatics as fuel additives and chemicals.

These outstanding contributions aim to provide a broad vision of the exciting possibilities of innovation in catalytic protocols for the production of renewable energies directed towards a more sustainable future. Both guest editors would like to profusely thank the contributors to this themed issue for providing their most high profile manuscripts, which will surely make the special issue a great success, as well as the editorial team from Chemical Society Reviews and the RSC for the opportunity to assemble the issue. Last but not least, we wish all readers a productive and enjoyable reading of these contributions, which we hope will stimulate further advances in the field in the near future.

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