Challenges and Opportunities for Carbon Dioxide Utilization

Abstract

Progress in CO2 Utilization: The studies assembled in this Special Issue of Energy Technology highlight the prospects and challenges in carbon dioxide utilization for greenhouse gas mitigation and the production of renewable fuels and chemicals. We thank all of our contributors and hope that our readership will share our excitement about this Special Issue. With the atmospheric levels of carbon dioxide being above 400 ppm today, marking the highest they have been in the past 400,000 years, significant pushes have being made to curb anthropogenic carbon emissions. While CO2 capture and subsequent geologic sequestration address CO2 emission problems, there is growing interest to monetize CO2 through value-added carbon utilization. Using fossil-fuel-based CO2 as a raw carbon material and supplementing renewable energy to produce value-added chemicals could potentially generate profits to subsidize the costs of CO2 capture and storage. This Special Issue of Energy Technology addresses many technologies for the utilization of carbon dioxide, ranging from thermal, electrochemical, and photochemical to biological conversion methods. Broad perspectives and feasibility studies on the field are also reviewed. Much of the work in this issue originated from presentations at the "CO2 Utilization" Symposium held at the 251st American Chemical Society National Meeting & Exposition in San Diego, California, in March 2016. Coupling carbon dioxide capture and utilization may yield synergistic benefits. Al-Mamoori et al. provide a perspective on the status of CO2 capture technologies, how the captured CO2 can be utilized, and how integrating these two activities can be beneficial. The use of polyethylenimine for CO2 capture and separation is reviewed by Shen et al. as a possible process for feeding pure CO2 to downstream conversion processes. An alternative is provided by Zevenhoven et al., considering the carbonization of CO2 as a storage media for the gas. When paired with renewable energy sources, carbon dioxide utilization becomes much more feasible, both in terms of economics and sustainability. The sources of CO2 and the energy being used are both important in determining the feasibility of the conversion processes, as described by Meier et al. in reviewing carbon dioxide as a feedstock in Switzerland, and by Navarrete et al. in utilizing renewable energy for carbon dioxide catalysis. Zimmermann and Schomäcker caution us, however, to be careful in comparing CO2 utilization technologies to each other, as the standardization of the field is still in its infancy. There are a multitude of technologies being investigated for the conversion of CO2, with the application, scale, and products varying widely. Thermal reduction of CO2 with H2 to form methane is one such option. Jimenez et al. studied supported cobalt nanorods as catalysts for this process, and El Sibai et al. investigated reactor design models for the methanation of carbon dioxide. Electrochemical conversion of CO2 has recently resulted in significant research activity. Much research is still needed in this area, in particular in electrocatalysis development and cell construction. Vickers et al. review gold, copper, and alloy materials as catalysts for CO2 electroreduction, showing how the type of metal, as well as the morphology of the metal, significantly impacts the catalyst properties and products. Electrocatalytic investigations for CO2-to-carbon monoxide conversion over silver nanoparticles using carbon foams and silver–zinc alloys were reported by Ma et al. and Hatsukade et al., respectively. Palladium–polyaniline catalysts were investigated by Zheng et al. to synthesize formic acid and methanol from CO2. Rough and nanoscale copper were shown to primarily form methane in the works by Karaiskakis and Biddinger and Merino-Garcia et al., respectively. The catalysis properties of CO2 electroreduction systems are not the only factors that dictate the performance of the systems; the membranes also play a significant role. Kutz et al. show that the membrane resistance should not be the only concern in development, and that incorporating imidazolium-functionalized polymers into the membranes could provide kinetic benefits by lowering the reaction overpotentials required for CO2 electroreduction. In addition to the electrically-driven reduction of CO2, photolytically-driven reduction of CO2 is being investigated. Jiao et al. reported their use of platinum nanoparticles supported on titania phonic crystals as photocatalysts for the conversion of CO2 to methane. Using high-pressure hydrogen and carbon dioxide, Miyano et al. photochemically synthesized methanol over layered double hydroxides. CO2 conversion is not limited only to chemical means of transformation. Biochemical systems are also utilized in converting CO2 to a variety of products. Schlager et al. provide a review on biocatalytic and bioelectrocatalytic reduction of CO2. As you can see from the variety of works compiled in this special issue, there are many opportunities to convert CO2 to useful products. We hope that you enjoy this special issue of Energy Technology. Thank you to all who contributed works to this issue and to the journal for hosting it. Hongfei Lin is an Associate Professor in the Voiland School of Chemical Engineering and Bioengineering at Washington State University. He received his B.E and M.S. degrees in Chemical Engineering from Tsinghua University, China, and his Ph.D. degree in Chemical Engineering from Louisiana State University. Prof. Lin has more than 15 years of industrial and academic experience on catalysis and reaction engineering. His current research focuses on developing sustainable processes coupled with multifunctional catalytic material systems for the production of fuels and chemicals using renewable feedstocks. He has authored more than 40 peer-reviewed scientific journal papers and delivered numerous presentations in conferences and research institutions. He is an active member of the American Chemical Society (ACS) and American Institute of Chemical Engineers (AIChE) and has regularly organized symposia and conference sessions in the areas of biomass conversion and CO2 utilization. Elizabeth J. Biddinger has been an Assistant Professor in the Department of Chemical Engineering at the City College of New York, CUNY since Fall 2012, and she is also on the Graduate Faculty in the City University of New York (CUNY) Chemistry Ph.D. Program. Her research interests encompass green chemistry and energy applications utilizing electrochemistry, catalysis, alternative solvents, and sustainable engineering methods. She received her B.S. in Chemical Engineering from Ohio University in 2005 and her Ph.D. in 2010 in Chemical Engineering from The Ohio State University, with the focus of her thesis work on PEM and direct methanol fuel cell cathode catalysts. Prior to joining City College, Professor Biddinger was a Postdoctoral Fellow at the Georgia Institute of Technology 2010-2012. She has more than 30 publications in the fields of electrocatalysis, electrodeposition, and the use of ionic liquids as novel solvents. Prof. Biddinger is active in The Electrochemical Society, American Chemical Society, and American Institute of Chemical Engineers.