Controlling Emission Wavelength and Chirality of Quantum Emitters in 2D Heterostructures
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Role of emission controls in reducing the 2050 climate change penalty for PM2.5 in China
Previous studies demonstrated that global warming can lead to deteriorated air quality even when anthropogenic emissions were kept constant, which has been called a climate change penalty on air quality. It is expected that anthropogenic emissions will decrease significantly in the future considering the aggressive emission control actions in China. However, the dependence of climate change penalty on the choice of emission scenario is still uncertain. To fill this gap, we conducted multiple independent model simulations to investigate the response of PM2.5 to future (2050) climate warming (RCP8.5) in China but with different emission scenarios, including the constant 2015 emissions, the 2050 CLE emissions (based on Current Legislation), and the 2050 MTFR emissions (based on Maximum Technically Feasible Reduction). For each set of emissions, we estimate climate change penalty as the difference in PM2.5 between a pair of simulations with either 2015 or 2050 meteorology. Under 2015 emissions, we find a PM2.5 climate change penalty of 1.43 µg m-3 in Eastern China, leading to an additional 35,000 PM2.5-related premature deaths [95% confidence interval (CI), 21,000-40,000] by 2050. However, the PM2.5 climate change penalty weakens to 0.24 µg m-3 with strict anthropogenic emission controls under the 2050 MTFR emissions, which decreases the associated PM2.5-related deaths to 17,000. The smaller MTFR climate change penalty contributes 14% of the total PM2.5 decrease when both emissions and meteorology are changed from 2015 to 2050, and 24% of total health benefits associated with this PM2.5 decrease in Eastern China. This finding suggests that controlling anthropogenic emissions can effectively reduce the climate change penalty on PM2.5 and its associated premature deaths, even though a climate change penalty still occurs even under MTFR. Strengthened controls on anthropogenic emissions is key to attaining air quality targets and protecting human health in the context of future global climate change.
Liu, Song↗
Distinct Seasonality in Aerosol Responses to Emission Control Over Northern China
Despite intensive research exploring how aerosols respond to emission control over Northern China, efforts mostly focus on the environmental benefit, especially in winter. Here we found that unlike the most substantial PM 2.5 concentration reduction in winter, aerosol optical depth (AOD) declines more than 2 times faster in summer, causing an increase in aerosol radiative effects of 1.2 (5.7)Wm -2 on all-sky (clear-sky) conditions over 2013–2019 and largely shaping the climate impact. Low-level aerosols are shown to be the prime contributor under the synergetic effects of aerosol composition and ambient relative humidity (RH). The dominance of the highly hygroscopic sulfate combined with high RH enables a strong extinction efficiency of the reduced summertime aerosols, while the insignificant AOD decline in wintertime result from the dominance of organic aerosols with weak hygroscopicity, and is further offset by the increased frequencies of extremely high RH. We show the environmental and climatic responses of aerosols to emission control exhibit distinctively different seasonality.
54 ENVIRONMENTAL SCIENCES↗
The Response of Summertime Organic Aerosol Composition to Emission Controls in the Northeastern United States
The responses of secondary organic aerosols (SOA) to emission controls remain uncertain due to the limited continuous long‐term measurements. Measurements of detailed carbonaceous aerosol composition in the New York City metropolitan region during the summers of 2001, 2009, 2011, and 2018 provide a look at the changes in summertime SOA over the past two decades when significant pollution reduction and emission controls occurred in the northeastern United States. Here, we show that the averaged nighttime SOA, especially the fresh local SOA, extreme mass concentrations resulted from anthropogenic volatile organic compounds reductions, while there is a little trend for the regional aged SOA. Meanwhile, these fresh SOA extremes occurred most often under conditions of high relative humidity during nighttime. The analysis presented here provides a comprehensive evaluation of the evolution of the increasingly important organic component of the submicron ambient aerosols in this major metropolitan area.
Zhang, Jie↗
System and method for thermal emission control using segmented array
The present disclosure relates to a thermal emissivity control system. The system may have a segmented array that makes use of a thermally conductive base layer configured to be connectable to an external heat generating subsystem, with the base layer including a thermally emissive surface. The array may also have a plurality of actuation elements at least one of positioned on or adjacent to the thermally emissive surface. A plurality of movable shutter elements is disposed adjacent one another in a grid pattern, and controlled in movement by the actuation elements to create gaps of controllably varying dimension therebetween. The shutter elements control at least one of a magnitude of, or direction of, thermal radiation through the gaps.
Panas, Robert Matthew↗
Techno-economic evaluation of emission control configurations for AMP/PZ-based post-combustion CO 2 capture
Minimizing the environmental impacts of amine-based post-combustion carbon capture technologies is essential for regulatory compliance and public acceptance. Experimental campaigns at RWE's CO 2 capture pilot plant in Niederaussem using CESAR1 demonstrated that combining existing emission abatement technologies can substantially reduce the concentration of amines and degradation products in the CO 2 -depleted flue gas to below the detection limit of an infrared spectrometer. The campaign confirmed that a proprietary dry bed technology (OEASE aerozone™) or a second water wash can reduce AMP and PZ emissions to below 1 mg/Nm 3 . However, an acid or chemically active wash downstream of the water wash is necessary to reduce NH 3 emissions to very low levels (<2 mg/Nm 3 ). Combining a dry bed with an acid wash significantly reduces both the required acid solution and the resulting acid waste. The techno-economic analysis indicates that implementing emission mitigation technologies provides substantial environmental benefits for the CESAR1 process, with only a marginal increase (<1 €/tCO 2 ) in both the carbon capture cost (CCC) and CO 2 avoidance cost (CAC). The additional capital cost associated with extra column packing is offset by operational cost savings from reduced solvent losses. For stringent emission permits targeting NH 3 , a configuration combining a dry bed upstream of the water wash followed by an acid wash achieves the best balance between emission control and cost efficiency. This configuration results in a Levelized Cost of Electricity (LCOE) of 143 €/MWh, a CCC of 45.4 €/tCO 2 , and a CAC of 88.4 €/tCO 2 .
AMP↗
Targeted electrochemical reduction of carcinogenic N -nitrosamines from emission control systems within CO 2 capture plants
N-Nitrosamines are one of the environmentally significant byproducts from aqueous amine-based post-combustion carbon capture systems (CCS) due to their potential risk to human health. Safely mitigating nitrosamines before they are emitted from these CO 2 capture systems is therefore a key concern before widescale deployment of CCS can be used to address worldwide decarbonization goals. Electrochemical decomposition is one viable route to neutralize these harmful compounds. The circulating emission control waterwash system, commonly installed at the end of the flue gas treatment trains to minimize amine solvent emissions, plays an important role to capture N-nitrosamines and control their emission into the environment. The waterwash solution is the last point where these compounds can be properly neutralized before becoming an environmental hazard. In this study, the decomposition mechanisms of N-nitrosamines in a simulated CCS waterwash with residual alkanolamines was investigated using several laboratory-scale electrolyzers utilizing carbon xerogel (CX) electrodes. Hcell experiments revealed that N-nitrosamines were decomposed through a reduction reaction and are converted into their corresponding secondary amines thereby neutralizing their environmental impact. Batch-cell experiments statistically examined the kinetic models of N-nitrosamine removal by a combined adsorption and decomposition processes. The cathodic reduction of the N-nitrosamines statistically obeyed the first-order reaction model. Finally, a prototype flow-through reactor using an authentic waterwash was used to successfully target and decompose N-nitrosamines to below the detectable level without degrading the amine solvent compounds allowing them to be return to the CCS and lower the system operating costs. Furthermore, the developed electrolyzer was able to efficiently remove greater than 98% of N-nitrosamines from the waterwash solution without producing any additional environmentally harmful compounds and offers an effective and safe route to mitigate these compounds from CO 2 capture systems.
20 FOSSIL-FUELED POWER PLANTS↗
Advanced Emission Control for High-Efficiency Engines
The CRADA between Cummins and Battelle will focus on: advanced emission control for high-efficiency engines. It will specifically focus on the following three areas: 1. Passive NOx absorbers - The purpose is to develop next generation materials that can be efficiently used to address the cold-operation, as driven by improved engine efficiency. 2. Oxidation of methane and short alkanes – The purpose is to address cold-operation emissions arising from CNG vehicles. 3. Improved understanding of particulates – The purpose is to understand how particulates are formed which will be used to develop strategies to address the tightening regulations and their enforcement for exhaust particulate matter. The first two areas will be based on PNNL’s technical leadership in the area of zeolite-based materials. The third area will have a shorter time scope to leverage the unique SPLAT capabilities at PNNL to help address Cummins’ needs in improving the understanding of particulates
02 PETROLEUM↗
Transformation of CeO 2 Nanoparticles into Atomically Dispersed Ce Cations Leads to Enhanced Reactivity for Automotive Emissions Control
Nanosized cerium oxide (CeO 2 ) has been extensively used as the oxygen storage component in automotive emission control systems. However, the possible influence of atomically dispersed Ce in these catalysts has not been recognized. Here, in this study, we demonstrate the controllable transformation of ceria nanoparticles into isolated cerium cations on γ-Al 2 O 3 via reductive atom trapping in 10% H 2 at 800 °C, achieving over half-monolayer coverage. Dispersed Ce 1 ions anchored by surface penta- and octa-coordinated Al sites exhibit outstanding thermal stability in air up to 500 °C, enabling further loading of active metals with well-defined catalyst structures. With this strategy, supported single-atom Rh 1 surrounded by dispersed Ce 1 is confirmed to exhibit much superior performance to Rh 1 on bare Al 2 O 3 or nanocrystalline CeO 2 in catalyzing NO reduction by CO, exhibiting a striking one-order-of-magnitude increase in activity. Dispersed Ce 1 exhibits greatly enhanced oxygen transfer capability compared to ceria nanoparticles and introduces a modified reaction mechanism that involves an adjacent Rh 1 –Ce 1 motif, resulting in a greatly decreased activation barrier (from 192 to 96 kJ/mol). The reactivity enhancements are also seen with Ce 1 -promoted Pt nanoparticles for oxidation of CO and hydrocarbons.
Jiang, Dong [Washington State Univ., Pullman, WA (↗
Controllable X-ray Pulse Trains from Enhanced Self-Amplified Spontaneous Emission
We report the demonstration of optical compression of an electron beam and the production of controllable trains of femtosecond, soft x-ray pulses with the Linac Coherent Light Source (LCLS) freeelectron laser (FEL). This is achieved by enhanced self-amplified spontaneous emission with a 2 μm laser and a dechirper device. Optical compression was achieved by modulating the energy of an electron beam with the laser and then compressing with a chicane, resulting in high current spikes on the beam which we observe to lase. A dechirper was then used to selectively control the lasing region of the electron beam. Field autocorrelation measurements indicate a train of pulses, and we find that the number of pulses within the train can be controlled (from 1 to 5 pulses) by varying the dechirper position and undulator taper. These results are a step toward attosecond spectroscopy with x-ray FELs as well as future FEL schemes relying on optical compression of an electron beam.
Duris, Joseph P↗
Spin-Correlated Radical Pairs as Magnetic Switches for Controlling Emissive Triplet States via Triplet–Triplet Energy Transfer
Magnetic fields offer a powerful means to control molecular emission, enabling quantum sensing and spin-level control of chemical reactions. Here, we demonstrate a strategy to magnetically control red to near-infrared phosphorescence via triplet–triplet energy transfer (TTET) from donor–chiral bridge–acceptor (D−χ–A) molecules that generate spin-correlated radical pairs (SCRPs) upon photoexcitation. These SCRPs yield non-emissive triplet excited states whose formation is sensitive to magnetic fields. Here, by transferring this energy to emissive Pt- and Pd-based π-extended porphyrins, we enable magnetic control over phosphorescence that would otherwise be unresponsive to weak magnetic fields (<1 T). This approach establishes a platform for quantifying magnetic field effects on silent triplet states while extending magnetically responsive emission into the near-infrared. Coupling SCRP-based molecular magnetic switches to long-wavelength emissive acceptors offers a new way for probing and modulating spin-dependent processes and triplet-state populations in molecular systems.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Transformation of Highly Stable Pt Single Sites on Defect Engineered Ceria into Robust Pt Clusters for Vehicle Emission Control
Engineering surface defects on metal oxide supports could help promote the dispersion of active sites and catalytic performance of supported catalysts. Herein, a strategy of ZrO 2 doping was proposed to create rich surface defects on CeO 2 (CZO) and, with these defects, to improve Pt dispersion and enhance its affinity as single sites to the CZO support (Pt/CZO). The strongly anchored Pt single sites on CZO support were initially not efficient for catalytic oxidation of CO/C 3 H 6 . However, after a simple activation by H 2 reduction, the catalytic oxidation performance over Pt/CZO catalyst was significantly boosted and better than Pt/CeO 2 . Pt/CZO catalyst also exhibited much higher thermal stability. The structural evolution of Pt active sites by H 2 treatment was systematically investigated on aged Pt/CZO and Pt/CeO 2 catalysts. With H 2 reduction, ionic Pt single sites were transformed into active Pt clusters. Much smaller Pt clusters were created on CZO (ca. 1.2 nm) than on CeO 2 (ca. 1.8 nm) due to stronger Pt-CeO 2 interaction on aged Pt/CZO. Consequently, more exposed active Pt sites were obtained on the smaller clusters surrounded by more oxygen defects and Ce 3+ species, which directly translated to the higher catalytic oxidation performance of activated Pt/CZO catalyst in vehicle emission control applications.
36 MATERIALS SCIENCE↗
The surprisingly inexpensive cost of state-driven emission control strategies
Traditionally, analysis of the costs of cutting greenhouse gas emissions has assumed that governments would implement idealized, optimal policies such as uniform economy-wide carbon taxes. Yet actual policies in the real world, especially in large federal governments, are often highly heterogeneous and vary in political support and administrative capabilities within a country. While the benefits of heterogeneous action have been discussed widely for experimentation and leadership, little is known about its costs. Focusing on the United States, we represent plausible variation (by more than a factor of 3) in the stringency of state-led climate policy in a process-based integrated assessment model (GCAM-USA). For a wide array of national decarbonization targets, we find that the nationwide cost from heterogeneous subnational policies is only one-tenth higher than nationally uniform policies. Such results hinge on two critical technologies (advanced biofuels and electricity) for which inter-state trade ameliorates the economic efficiencies that might arise with heterogeneous action.
Peng, Wei↗
Impact of Mg on Pd-based Methane Oxidation Catalysts for Lean-burn Natural Gas Emissions Control
More efficient lean-burn, natural gas engines are limited by greenhouse gas emissions due to methane oxidation catalysts (MOC) that suffer from water inhibition and high temperature activation. Herein, we report that the addition of Mg to supported 1 wt.% Pd MOCs improved hydrothermal stability even after severe hydrothermal aging. The superior methane oxidation activity compared to the corresponding Mg-free catalyst was attributed to (1) influence of Mg during surface roughening and restructuring at 700 °C on metal-support interaction, (2) reducibility of PdOx sites and (3) preferential stabilization of active Pd (1 0 0) facets in the sample as was evidenced by H 2 TPR and CO TPD characterization experiments. Methane conversion under synthetic exhaust conditions relevant to natural gas, lean-burn engines were investigated. In conclusion, BET, TPR, CO pulse chemisorption followed by TPD provided valuable insights into the surface area, pore volume, reducibility, Pd dispersion and Pd particle size of the selected catalyst samples.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Co-Optimization Scheme for Hybrid Electric Vehicles Powertrain and Exhaust Emission Control System Using Future Speed Prediction
Hybrid electric vehicles (HEVs) have been an effective solution for improved vehicle fuel efficiency and reduced emission pollution. In this paper, a co-optimization scheme is proposed to optimize fuel efficiency for HEVs. Here, the proposed optimization scheme uses obtainable future speed prediction as the basis to optimally tune control parameters for the existing powertrain control system. The ramp-up time of the catalyst temperature to reach its light-off level in the exhaust emission system is also considered as an additional optimization constraint to reduce emission. The Toyota Prius Hybrid Simulink model which is an integrated model for a powertrain and exhaust emission system is validated using real data from several real driving cycle scenarios. Then, to simplify the formulation of the proposed algorithm, the model for the optimization for powertrain and exhaust emission systems is represented by a set of equivalent neural network (NN) models learned using the data generated from the well-validated Toyota Prius Hybrid Simulink model. Using NN models, a co-optimization algorithm is established that provides an optimal tuning of some fuel-sensitive powertrain control parameters using future speed prediction, leading to a novel co-optimization algorithm, achieving on average a further 9.22% fuel savings for the Toyota Prius Hybrid Simulink model.
33 ADVANCED PROPULSION SYSTEMS↗
Methods and systems for emissions control in solvent-based CO2 capture processes using CO2
A method with corresponding systems for reducing emission of amines to the atmosphere. The method includes a a) introducing a gas containing CO 2 into an absorber; b) flowing the flue gas through an absorber having an absorbent with a water-lean solution having less than 50% water and one or more amines, with the absorbent capturing the CO 2 and forming a reduced CO 2 content gas having a baseline CO 2 content; and c) washing the reduced CO 2 content gas in a wash column with a wash solution comprising carbonic acid formed by addition of gaseous CO 2 into the wash solution. In this method, the washing removes the amines from the reduced CO 2 content gas and produces a reduced amine content gas exiting from the wash column.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
A Review on the Impact of SO 2 on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis
A high-efficiency after-treatment technology has been required to meet the increasingly stringent regulations on the emissions of nitrogen oxides (NO x ), hydrocarbons (HCs), and carbon monoxide (CO) exhausts from diesel engine vehicles throughout the world. The diesel oxidation catalyst (DOC) is an indispensable part of a diesel-fueled exhaust system, which mainly functions in the oxidation of unburned HCs and CO to CO 2 and H 2 O (in the case of HCs) and a proportion of NO to NO 2 . However, the DOC will unavoidably be poisoned by trace gaseous SO 2 or accumulated sulfur on the catalyst under real operational conditions and hence impair the overall purification efficiency of the aftertreatment system. There have been significant research efforts from both academia and industry involving sulfur-relevant diesel oxidation chemistry and development of robust sulfur-resistant oxidation catalysts. In this review, we focus on recent advances in the study of SO 2 effects on the catalytic oxidation of NO, HCs, and CO over DOCs, with particular attention to the fundamentals beneath apparent observations of sulfur influence on PGM-based and non-noble metal-based catalysts in the different oxidation reactions. Regeneration methods and design rationale for sulfur-resistant catalysts are also covered. Several challenges in the future research regarding microscopic insights into the SO 2 -influencing mechanism and next-generation sulfur-resistant DOC design are highlighted toward real-world practice.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Reduced Precious Metal Catalysts for CH 4 and NO x Emission Control of Natural Gas Vehicles
The abundant domestic natural gas resources coupled with the desire for clean air and reduced greenhouse gas emissions motivates the accelerated development of natural gas vehicles (NGVs) and engine. Methane (CH 4 ), a potent greenhouse gas, is the major component of natural gas. The current emission catalysts fall short in meeting the desired exhaust CH 4 emission standards for NGVs. In this project we have developed a class of novel Platinum Group Metal (PGM) basedmonolith catalysts with enhanced activity.
03 NATURAL GAS↗