CO2 Reduction Technologies Research Articles

Selectivity and Efficiency of Heat Treated Sputter Deposited Thin Films of Copper towards the Carbon Dioxide Electro-reduction

The CO2 electro-reduction has the potential to store energy from intermittent renewable sources and to produce valuable carbon-neutral fuels or chemical feedstocks. However, current CO2 reduction technologies are challenged by high overpotentials, poor overall faradaic efficiencies (FE) and low selectivity, producing a mixture of carbon monoxide, methane, ethylene, formate, methanol, ethanol, and others. Catalyst performance is a significant contributor to these factors due to multiple proton-coupled electron transfer steps of CO2 electro-reduction reaction [1-3]. Recent experimental studies on Cu electrocatalysts have shown that higher CO2 and CO reduction efficiencies and selectivities towards certain valuable products could be achieved by modifying these metallic electrodes [4, 5]. For example, Cu thin films prepared by electrochemically reduced thermally grown Cu oxide (Cu2O) layers exhibit dramatically improved selectivity towards ethanol at significantly lower potentials (up to 50% FE at -0.35 V vs. RHE) in comparison to non-treated Cu catalysts (»3% FE at -0.35 V vs. RHE) [5]. Herein, inspired by these studies, we will present detailed examination of modified Cu thin film electrodes for CO2 reduction. Cu thin films are fabricated by reactive sputter deposition and subsequently modified by heat treatment varying the temperature and time of exposure. A combination of SEM/EDX, XRD and XPS were used for physico-chemical characterization. Whereas, CO2 electro-reduction products were monitored using in line GC for gas products and capillary GC, IC, NMR for liquid products. The results show that these modified Cu surfaces can improve the selectivity and efficiency of the catalyst. Acknowledgements Financial support of this work by the Swiss Competence Center for Energy Research Heat and Electricity Storage, the Competence Center Energy and Mobility, and Swiss Electric Researach and the Swiss Federal Office of Energy are greatly acknowledged.

Exergetic and Exergoeconomic Analysis of Three Different Technologies for Post-combustion CO2 Capture

The last decades have seen a fast rise in global greenhouse-gas (GHG) emissions by more than one-quarter, with CO2 accounting for 60% of all anthropogenic GHG emissions and the energy sector representing two-thirds of the total. Carbon Capture and Storage (CCS) has been acknowledged as a technology for CO2 reduction, however development in lowering the cost and energy consumption remains an important challenge. One tool that can be used for optimizing the energy consumption of capture is the application of an exergy-based analysis including an exergetic and exergoeconomic analysis. This paper aims to develop an exergy-based analysis and compare the results of different post-combustion CO2 capture technologies using MEA chemical absorption, gas separation membranes and vacuum/pressure swing adsorption (VPSA). The results show that liquid/gas processes such as chemical absorption using MEA solvent has a total irreversibility almost double that of gas/gas processes such as gas separation membranes or vacuum /pressure swing adsorption.

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting technology development and demonstrative research programs related to SOFC, as one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of their achievements was the-first-in-the-world commercialization of SOFC-based combined heat and power (CHP) system “ENE-FARM type S” in 2011. In June 2014, the Ministry of Economy, Trade and Industry (METI) has compiled a Strategic Road Map for Hydrogen and Fuel Cells. It was established, releasing fuel cells for commercial and industrial use onto the market in 2017 as one of the processes of expanding the use of fuel cell technology. NEDO’s activities and recent trends on SOFC, including a program “Technology development for promoting SOFC commercialization” , will be overviewed.

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting development and demonstrative research projects relating to the solid oxide fuel cell (SOFC), as it is one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of NEDO’s achievements was the world’s first commercialization of an SOFC-based combined heat and power (CHP) system called ENE-FARM type S in 2011. In June 2014, Japan’s Ministry of Economy, Trade and Industry (METI) formulated its Strategic Road Map for Hydrogen and Fuel Cells. In accordance with the road map, it was planned to release fuel cells for commercial and industrial use onto the market in 2017 as one of the processes for expanding the use of fuel cell technology. NEDO’s activities, including its Technology Development for Promotion of Practical Applications of Solid Oxide Fuel Cells project, and recent trends in the SOFC field, are overviewed here.

Laboratory-scale experiment on a novel mineralization-based method of CO2 capture using alkaline solution

We propose a novel CO2 conversion technology that is based on use of an alkaline solution. In this investigation, alkaline solutions were used to fix CO2 in the presence of K+, Na+, and Ca2+ ions. NaOH and KOH were selected and used at a 30 wt% in H2O. All the experiments were conducted under normal temperature and pressure conditions to reduce the total energy in the system. We also used a 30 wt% mono-ethanolamine (MEA) solution to make a comparison with the selected alkaline solution. Metal ions were supplied as Ca2+ from a CaO solution. The product precipitate was then analyzed by X-ray diffraction. We found that the selected alkaline solution formed a metal carbonate by reacting with injected CO2. The NaOH and KOH solutions reacted directly with the CO2. The NaOH did not form CaCO3 in the first conversion experiment. However, its CO2 reduction capacity was dramatically increased after a CaO solution was added. In addition, we believe that the formed precipitates could be used in various industries. Therefore, this research contributes not only to the basic research into alternatives to the use of an MEA solution for CO2 fixation, but may also be applicable to CO2 reduction technologies.

Plasmon-Enhanced Photocatalytic CO2 Reduction Using Colloidal Nanocrystals

Using inputs of only sunlight, electricity, carbon dioxide, and water, photocatalytic CO2 reduction could mitigate the effects of climate change caused by the burning of fossil fuels and produce valuable fuels or chemical feedstocks. However, current CO2 reduction technologies suffer from high overpotentials and low selectivity, producing a mixture of carbon monoxide, methane, ethylene, formate, methanol, and others. Plasmon-assisted photocatalytic CO2 reduction leads to greater selectivity and lower overpotentials by unlocking unique mechanistic pathways. It has been well-documented that the strongly localized near fields at the surface of plasmonic nanoparticles promote electron-hole pair generation in nearby semiconductors.1–3 Plasmon decay generates an excited “hot” electron which can be transferred to a surface molecule for direct reduction or injected into an adjacent wide band gap catalyst, effectively limiting carrier recombination through charge separation and expanding the usable portion of the solar spectrum.4–7 The electron dynamics in an irradiated plasmonic nanoparticle can alter the electronic coupling with surface adsorbed CO2 and reaction intermediates, thereby changing the binding energy of these species and the catalytic properties of the plasmonic metals. The wide tunability of the plasmon resonance frequency with shape, size, and material confers fine control over these catalytic mechanisms, allowing for optimization of the photocatalytic performance. To take advantage of plasmonic catalysis, nano-sized spheres, cubes, and wires of gold, silver, and copper have been synthesized as these materials exhibit strong plasmonic and electrocatalytic behavior. For the semiconducting component of the photoelectrodes, nanostructured TiO2 co-catalysts have also been prepared. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to determine the shape and size distribution of the nanoparticles. X-ray diffraction (XRD) and optical spectroscopy were employed to characterize the electrodes. The CO2 reduction ability of the plasmonic metal nanoparticles with and without a semiconductor co-catalyst has been tested in a custom glass photoelectrochemical cell coupled to a light source and gas chromatograph-mass spectrometer (GC-MS) that allows detection and quantification of gaseous products. Ex-situ high performance liquid chromatography (HPLC) was used to quantify liquid products. (1) Thomann, I.; Pinaud, B. A.; Chen, Z.; Clemens, B. M.; Jaramillo, T. F.; Brongersma, M. L. Nano Lett. 2011, 11, 3440–3446. (2) Ingram, D. B.; Linic, S. J. Am. Chem. Soc. 2011, 133, 5202–5205. (3) Gao, H.; Liu, C.; Jeong, H. E.; Yang, P. ACS Nano 2012, 6, 234–240. (4) Mukherjee, S.; Zhou, L.; Goodman, A. M.; Large, N.; Ayala-Orozco, C.; Zhang, Y.; Nordlander, P.; Halas, N. J. J. Am. Chem. Soc. 2014, 136, 64–67. (5) Mubeen, S.; Lee, J.; Singh, N.; Krämer, S.; Stucky, G. D.; Moskovits, M. Nat. Nanotechnol. 2013, 8, 247–251. (6) Naya, S.; Teranishi, M.; Isobe, T.; Tada, H. Chem. Commun. 2010, 46, 815–817. (7) Lee, J.; Mubeen, S.; Ji, X.; Stucky, G. D.; Moskovits, M. Nano Lett. 2012, 12, 5014–5019.

Thickness- and Particle-Size-Dependent Electrochemical Reduction of Carbon Dioxide on Thin-Layer Porous Silver Electrodes.

The electrochemical reduction of CO2 can not only convert it back into fuels, but is also an efficient manner to store forms of renewable energy. Catalysis with silver is a possible technology for CO2 reduction. We report that in the case of monolithic porous silver, the film thickness and primary particle size of the silver particles, which can be controlled by electrochemical growth/reduction of AgCl film on silver substrate, have a strong influence on the electrocatalytic activity towards CO2 reduction. A 6 μm thick silver film with particle sizes of 30-50 nm delivers a CO formation current of 10.5 mA cm(-2) and a mass activity of 4.38 A gAg (-1) at an overpotential of 0.39 V, comparable to levels achieved with state-of-the-art gold catalysts.

Redox performance of Cu-based oxygen carrier used in chemical looping air separation combined oxy-fuel combustion technology

Chemical looping air separation offering the oxygen source to oxy-fuel combustion is an effective CO2 and NOx reduction technology in fossil fuel combustion. In the technology, oxygen carrier releases oxygen to flue gas and the reduced oxygen carrier absorbs oxygen from air in two separated reactors. And then the oxygen enriched flue gas returns to the combustor. The redox performance of oxygen carrier is essential to this technology. Thermodynamic calculations on CuO/Cu2O in flue gas atmosphere indicate that the redox reaction of copper oxides is not affected by the compositions in the flue gas. The optimization reduction temperatures are determined as 850~1050 °C. The redox performance of Cu-based oxygen carriers with 40wt%, 50wt%, 60wt% MgAl2O4 as inert binder was investigated in TGA and fixed-bed reactor. The reduction rate increases with temperature increasing and with oxygen concentration decreasing. The oxidation rate increases with temperature increasing when temperature is lower than 850 °C, while it begins to decrease when temperature is higher than 850 °C. The highest oxygen concentration in the reduction period is not limited to the gas flow but to the Pe at that temperature. The reduction and oxidation rates all increase with binder adding ratio decreasing. The average reaction rate of oxygen carrier begins to decrease when conversion is higher than 80%. The reduced oxygen carrier can be oxidized in low oxygen concentration.

Optimal Low Carbon Cement Production Cost via Co-processing and Carbon Capture and Storage

Cement production is recorded to have released about 5 % of current global man-made CO2 emissions. They came from the burning of fossil fuel in kiln, electricity usage from grinding of raw and finished materials, and from the calcination of main raw material; limestone to produce clinker. This paper objective is to find the best minimized solution of cement production cost while reducing CO2 emission and without compromising the quality of cement product. This is achieved by developing mathematical optimisation model that will be executed using General Algebraic Modelling System (GAMS). Some of data used in this research will be costs to install the technologies, costs of raw materials and fuels, properties of raw materials, CO2 emission improvements from CO2 reduction technologies and others. CO2 reduction technologies for cement industry considered in this study are co-firing (co-process) and carbon capture and storage. This paper also discusses the best combination of energy efficient technologies to meet the CO2 reduction target and product specification.

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting technology development and demonstrative research programs related to SOFC, as one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of their achievements was the-first-in-the-world commercialization of SOFC-based combined heat and power (CHP) system “ENE-FARM type S” in 2011. In June 2014, the Ministry of Economy, Trade and Industry (METI) has compiled a Strategic Road Map for Hydrogen and Fuel Cells. It was established, releasing fuel cells for commercial and industrial use onto the market in 2017 as one of the processes of expanding the use of fuel cell technology. NEDO’s activities on SOFC, including a program “Technology development for promoting SOFC commercialization” , will be overviewed.

Current Status of National SOFC Projects in Japan

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting technology development and demonstrative research programs related to SOFC, as one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of their achievements was the-first-in-the-world commercialization of SOFC-based combined heat and power (CHP) system “ENE-FARM type S” in 2011. In June 2014, the Ministry of Economy, Trade and Industry (METI) has compiled a Strategic Road Map for Hydrogen and Fuel Cells. It was established, releasing fuel cells for commercial and industrial use onto the market in 2017 as one of the processes of expanding the use of fuel cell technology. NEDO’s activities on Solid Oxide Fuel Cell (SOFC), including a program “Technology development for promoting SOFC commercialization”, will be overviewed.

Solid Adsorbents for Low-Temperature CO2 Capture with Low-Energy Penalties Leading to More Effective Integrated Solutions for Power Generation and Industrial Processes

CO2 capture represents the key technology for CO2 reduction within the framework of CO2 capture, utilization, and storage (CCUS). In fact, the implementation of CO2 capture extends far beyond CCUS since it will link the CO2 emission and recycling sectors, and when renewables are used to provide necessary energy input, CO2 capture would enable a profitable zero- or even negative-emitting and integrated energy-chemical solution. To this end, highly efficient CO2 capture technologies are needed, and adsorption using solid adsorbents has the potential to be one of the ideal options. Currently, the greatest challenge in this area is the development of adsorbents with high performance that balances a range of optimization-needed factors, those including costs, efficiency, and engineering feasibility. In this review, recent advances on the development of carbon-based and immobilized organic amines-based CO2 adsorbents are summarized, the selection of these particular categories of materials is because they are among the most developed low temperature (<100 oC) CO2 adsorbents up to date, which showed important potential for practical deployment at pilot-scale in the near future. Preparation protocols, adsorption behaviors as well as pros and cons of each type of the adsorbents are presented, it was concluded that encouraging results have been achieved already, however, the development of more effective adsorbents for CO2 capture remains challenging and further innovations in the design and synthesis of adsorbents are needed.

Generation of electricity from CO2 mineralization: Principle and realization

Current CO2 reduction and utilization technologies suffer from high energy consuming. Thus, an energy favourable route is in urgent demanding. CO2 mineralization is theoretically an energy releasing process for CO2 reduction and utilization, but an approach to recovery this energy has so far remained elusive. For the first time, here we proposed the principle of harvesting electrical energy directly from CO2 mineralization, and realized an energy output strategy for CO2 utilization and reduction via a CO2-mineralization fuel cell (CMFC) system. In this system CO2 and industrial alkaline wastes were used as feedstock, and industrial valuable NaHCO3 was produced concomitantly during the electricity generation. The highest power density of this system reached 5.5 W/m2, higher than many microbial fuel cells. The maximum open circuit voltage reached 0.452 V. Moreover, this system was demonstrated viable to low concentration CO2 (10%) and other carbonation process. Thus, the existing of an energy-generating and environmentally friendly strategy to utilize CO2 as a supplement to the current scenario of CO2 emission control has been demonstrated.

Plant derived porous graphene nanosheets for efficient CO2capture

There is an urgent need for the mitigation of climate change through CO2 reduction technologies. In this work, we demonstrate a novel method for production of porous graphene-like nanosheets (PGLNS) from the lignocellulosic fiber of oil palm empty fruit bunches (EFB) by a thermal graphitization technique for efficient CO2 capture. We used a wide range of microscopic and spectroscopic techniques to provide insights into the morphological and structural characteristics of the synthesized PGLNS (with d-spacing of ∼0.35 nm and pore size of <1 nm) obtained from the EFB biomass. The PGLNS show excellent performance as adsorbents for post-combustion CO2 capture. At 25 °C and 1 bar pressure, the maximum CO2 uptake was 2.43 mmol g−1 which is considerably higher than other competitive CO2 adsorbents, including zeolite, activated carbon and some metal organic frameworks. The selectivity of the PGLNS for CO2 over N2 (SCO2/N2 = 18.7), computed from single component isotherms at conditions pertinent to post-combustion applications, is also much higher than that of most of the previously reported adsorbents. Moreover, the significantly low isosteric heat of adsorption (∼21 kJ mol−1) revealed the possibility of desorbing CO2 and regenerating the PGLNS for their repeated use at a much lower energy penalty.

A graphical approach for the planning and design of a low carbon product

CO2 is being emitted throughout a product’s life cycle, i.e., during the material acquisition and extraction, materials transportation, product manufacturing and disposal. Strategies such as product path selection, supply chain planning, product reuse and recycling, fuel switching, conversion of waste to energy and carbon sequestration can contribute to carbon emission minimisation at the different stages of a product’s life cycle. A Carbon Supply Chain Product Curve (CSCPC), and an extended Systematic Hierarchical Approach for Resilient Process Screening (SHARPS) are proposed to evaluate a product CO2 emission throughout its supply chain and to select the suitable, and economically viable CO2 minimisation strategies. The proposed method has been tested to plan and design a low carbon palm cooking oil. Palm oil milling is determined as the major emission contributor in the palm cooking oil life cycle. High CO2 reduction technologies require more investment and are less profitable. By using the CSCPC-SHARPS tool, CO2 reduction can be a cost-effective, and result in low carbon emission. Application of the approach on a case study shows a potential reduction of 70.8 % carbon emissions as compared to the conventional palm oil supply chain carbon emission.

High-Heat-Resistance Polymers for SiC Power Modules

Power semiconductor devices are critical to CO2-reduction technology. In this study, we focus on a silicon carbide (SiC) device with a wide bandgap (WBG), which operates with low loss and high efficiency at temperatures up to 300°C. Conventional isolation/sealing technologies are unable to cope with such high operating temperatures; therefore, new advanced materials are necessary. In this report, we introduce SiC power module platforms to evaluate an alternative technology involving various encapsulating materials, bonding materials, and techniques for assembly. We attempted to produce four types of platforms, PT-1 through PT-4. Fig. 1 presents the cross section and a photograph of the platform PT-3, which was assembled from a Si insulated-gate bipolar transistor (IGBT) and a SiC diode. A simulation analysis was performed to evaluate the optimum properties of the platforms from the viewpoint of their reliabilities. The purpose of this project is to accelerate the development of high-heat-resistance materials and bonding technologies through the abovementioned evaluation platforms. We identify this project as “KAMOME-PJ (Kanagawa Advanced Module for Material Evaluation).” As a pertinent example, we report a novel polymer alloy having both high heat resistance and low thermal expansion (CTE). This alloy was prepared by melt mixing of two compounds,bismaleimide diphenyl methane (BMI) and 3,3’-(methylen-1,4-diphenylen) -bis(3,4-dihydro-2H-1,3-benzoxazine) (P-d). The resin comprising BMI 1.0 vs. P-d 0.3 exhibited superior thermal properties and processability. When cured at only 200°C for 4 h, the glass transition temperature of the resulting product was above 300°C. An encapsulation material was prepared using this polymer alloy, whose properties are described in Table 1 and are compared to those of conventional epoxy materials.

High Value Added Utilization of Vanadium Slag

Vanadium slag is a kind of common furnace slags in the metallurgical field that contains rich vanadium oxides and iron oxides. The high value added utilization of vanadium slag was exploratory studied in this paper. Under the existing experimental conditions, chemical reactions conducted between vanadium slag and concentrated sulfuric acid. Vanadium titanium catalyst was prepared with the lixivium (whose main ingredients were 44.42% of V2O5 and 29.36% of TiO2), which could meet the demand of industrial production; zeolite 4A was prepared creatively with leach residue of vanadium slag for the first time and its feasibility in CO2 capture was verified via detecting the CO2/N2 adsorption capacity. It is feasible to recycle solid wastes efficiently, reduce the environmental pollution and promote the development of CO2 reduction technology by this means.

Ecological Restoration Approaches for CO&lt;sub&gt;2&lt;/sub&gt; Emission from a Large Gas Field at Operation Period

The capacity of a large gas field is up to hundreds of billions of cubic metres, and percentage of the CO2 volume in raw gas is 8%~10%. Estimated by survey data and empirical equations, over 60% of the total emission from the gas field can be absorbed and utilized by regional crops and vegetation, and nearly a million tons per year exhausted. Based on analysis of mechanism and effect of CO2 influence on regional plants, soil and atmosphere, approaches for regional ecological restoration are put forward, including the approach of regional crops restoration, other plants restoration, ecological landscape reconstruction, and CO2 reduction technologies. This study provides reference for sustainable development of other gas field in low carbon era.

Forecasting Co2 Mitigation and Policy Options for China's Key Sectors in 2010–2030

The technological status of seven key sub-sectors in three sectors (energy, industry and consumption) was analysed using bottom-up modelling. Using 2010 as a baseline, the paper predicts direct CO2 emission trends, turning points, reduction potentials and costs for the three sectors in two policy scenarios and three technology scenarios for the years 2015, 2020 and 2030. The scenario analysis shows that the industry sector might reach its emissions peak between 2015 and 2020, which leaves more emission reduction potential for the consumption sector. CO2 emissions in the consumption sector will increase through to 2030 without reaching a turning point. In the Social Low Control Middle (SL-CM) scenario, CO2 reduction technology potentials of the industry and consumption sectors will reach 0.84 billion tonnes CO2-eq by 2020. Within this, production contributes 13% of reductions, transportation 48%, and construction 39%. In the 2030SL-CM-scenario, the CO2 reduction potentials rise to 1.6 billion tonnes CO2-eq, within which production contributes 8%, transportation 44% and construction 48%. In building China's Emission Trading Scheme (ETS), the government should pay more attention to a low carbon consumption policy rather than a traditional CO2 control policy for the industrial sector.

Integrated assessment of CO2 reduction technologies in China's cement industry

The main objective of this article is to evaluate CO2 mitigation potential and to calculate costs avoided by the use of different CO2 mitigation technologies in China's cement sector, namely energy efficiency improvements, use of alternative fuels, clinker substitution and carbon capture and storage (CCS). Three scenarios are designed based on the projection of cement output and technology development over the next 40 years (2010–2050). 2.5, 4.7 and 4.3Gttonnes of CO2 will be saved totally in basic scenario and two low carbon scenarios up to 2050. By comparing these technologies along the scenarios, it can be concluded that CO2 emissions can mainly be reduced by energy efficiency improvements and use of alternative fuels. Clinker substitution, which reduces the clinker-to-cement ratio as well as energy intensity, results in significant cost advantages. CCS, including post-combustion capture and oxy-fuel combustion capture, could play an important role in the capture of CO2 in the cement industry, and is expected to be in commercial use by 2030.