Recent progress of amine modified sorbents for capturing CO2 from flue gas

Under the Paris agreement, China has committed to reducing CO_2 emissions by 60%–65% per unit of GDP by 2030.Since CO_2 emissions from coal-fired power plants currently account for over 30% of the total carbon emissions in China, it will be necessary to mitigate at least some of these emissions to achieve this goal. Studies by the International Energy Agency(IEA) indicate CCS technology has the potential to contribute 14% of global emission reductions, followed by 40% of higher energy efficiency and 35% of renewable energy, which is considered as the most promising technology to significantly reduce carbon emissions for current coal-fired power plants.Moreover, the announcement of a Chinese national carbon trading market in late 2017 signals an opportunity for the commercial deployment of CO_2 capture technologies.Currently, the only commercially demonstrated technology for post-combustion CO_2 capture technology from power plants is solvent-based absorption. While commercially viable, the costs of deploying this technology are high. This has motivated efforts to develop more affordable alternatives, including advanced solvents, membranes,and sorbent capture systems. Of these approaches, advanced solvents have received the most attention in terms of research and demonstration. In contrast, sorbent capture technology has less attention, despite its potential for much lower energy consumption due to the absence of water in the sorbent. This paper reviews recent progress in the development of sorbent materials modified by amine functionalities with an emphasis on material characterization methods and the effects of operating conditions on performance. The main problems and challenges that need to be overcome to improve the competitiveness of sorbent-based capture technologies are discussed.

Feature Extraction and Diagnosis System Using Virtual Instrument Based on CI

Through investigating intelligent diagnosis method of Computational Intelligence (CI) and studying its application in fault feature extraction, a gear fault detection and Virtual Instrument Diagnostic System is developed by using the two hybrid programming method which combines both advantages of VC++ and MATLAB. The interface is designed by VC++ and the calculation of test data, signal processing and graphical display are completed by MATLAB. The pro-gram converted from M-file to VC++ is completed by interface software, and a various multi-functional gear fault di-agnosis software system is successfully obtained. The software system, which has many functions including the intro-duction of gear vibration signals, signal processing, graphical display, fault detection and diagnosis, monitoring and so on, especially, the ability of diagnosing gear faults. The method has an important application in the field of mechanical fault diagnosis.

In situ monitoring of Suzuki-Miyaura cross-coupling reaction by using surface-enhanced Raman spectroscopy on a bifunctional Au-Pd nanocoronal film

Surface-enhanced Raman spectroscopy(SERS), a powerful surface vibrational spectroscopic technique, is ideally suited for in situ monitoring the chemical transformations occurred at surfaces and/or interfaces.For in situ SERS monitoring, a platform integrated both plasmonic and catalytic activity is a prerequisite. Here, we fabricate a bifunctional Au-Pd nanocoronal film for in situ SERS monitoring Suzuki-Miyaura cross-coupling reaction. This excellent bifunctional substrate leads to the coupling of high catalytic activity with a strong SERS effect at the center of two adjacent Au cores and shows fine reproducibility and stability of SERS signals. During investigating the Suzuki reaction with in situ SERS, we found two distinct catalytic kinetic processes resulted from two disparate catalytic sites on a Au-Pd nanocoronal. Comparing with conventional analytical techniques, this work provides a novel approach for studying Suzuki reactions at surfaces and/or interfaces with in situ SERS.

Boosting Plasmonic Hot Electron Utilization for Visible-Light Photocatalysis Using Polarized Ag-TiO_(2) Nanoparticles

Plasmonic hot electrons have long been regarded as a promising energy source for inducing chemical transformations.However,because of the mismatch between the electron cloud of reactant molecules and the hot-electron gas of metal nanoparticles(NPs),the highly localized and short-lived hot electrons are dif-ficult to utilize in bulk synthesis when the reactant molecules do not have a strong affinity for the metal surface.Here,we propose the concept of polarized nanocatalysts to mimic chemical polarity at the nanometer scale.Under plasmonic photorecycling conditions,the rationally designed asymmetric Ag-TiO_(2) hybrid NPs enable six-electron reduction of molecules in bulk solution.This hot-electron-driven reaction does not require a conventional hydrogen or hydride reducing agent.As a proof-of-concept,one-pot photocatalytic syntheses of amides,such as paracetamol,using nitro reactants were performed.This provides a new opportunity to enable challenging multielectron transformations in organic chemistry.

Studies on pathways to carbon neutrality for indirect coal liquefaction in China

The production capacity of indirect coal liquefaction(ICL)in use in China has reached a level of 8 million t/a,which corresponds to a carbon footprint of>60 million t/a.ICL is facing mountainous pressure to reduce its carbon emissions when its development is planned with carbon neutrality as a background objective.This paper studies the pathways that can lead to carbon neutrality for ICL in China,constructing four carbon-neutral pathways for ICL systems with the introduction of green hydrogen,biomass as feedstock and with CCS(carbon capture and storage),which can reduce significant carbon emissions from coal-gasification and water-gas shift processes.The carbon-neutral biomass is used to replace some coal as co-feed to gasification and combustion,leading to reduced carbon emissions as well.Calculations and economic analyses are performed on different carbon-reduction pathways using a carbon-neutral ICL system on a 1 million t/a scale as an example.The results are that the pathway of direct coal substitution with biomass is the lowest carbon-reduction route at RMB 31-125/t CO_(2),substitution with green hydrogen costs the highest at RMB 84-422/t CO_(2) and CCS costs are in the middle at RMB 96-148/t CO_(2).Each pathway has its pros and cons,and a combination of the three may be used for the best outcome.Furthermore,a comprehensive study and systematic summation of the critical technological processes and their underlying challenges for carbon-neutral ICL together with direction for a technological breakthrough are presented.These ICL carbon-reduction pathways presented in this paper are capable of realizing an integrated development between fossil and renewable energy sources,helping the carbon-intense coal-chemical industries to achieve their goals of carbon peak and carbon neutrality.

Research progress in green synthesis of ammonia as hydrogen-storage carrier under‘hydrogen 2.0 economy’

Hydrogen energy is characterized by its environmental friendliness,high efficiency,lack of carbon emissions and wide range of applications.However,its transportation and storage are challenges that limit further development of the hydrogen-energy industry.Ammonia is a carbon-free hydrogen-rich carrier.The storage of hydrogen in ammonia has unique advantages of high energy density,easy storage and transportation,reliable safety,a mature industrial foundation and no tail-end carbon emissions.However,industrial ammonia synthesis still heavily relies on the Haber-Bosch process,which accounts for significant energy consumption and greenhouse gas emissions.Therefore,the development of green and sustainable ammonia-synthesis methods is extremely important and urgent.Recently,ammonia-synthesis technologies such as electrocatalysis,photocatalysis,photoelectrocatalysis and biocatalysis have successfully produced ammonia from nitrogen and water,resulting in lower costs.The nitrogen-reduction-reaction conditions of these methods are mild and can be carried out under ambient temperatures and atmospheric pressure with low energy consumptions.Meanwhile,these methods bypass the traditional hydrogen-production section and their routes are simpler.Therefore,these technologies can be used to flexibly integrate renewable energy,including intermittent renewable energy,to achieve distributed ammonia synthesis.These benefits contribute to both global energy and environmental sustainability goals.In this study,the mechanisms of ammonia synthesis under ambient conditions are reviewed and the technical difficulties of various catalysts for ammonia synthesis are summarized.Based on the optimization strategies reported for various catalysts,the high-performing catalysts reported for ammonia synthesis are reviewed and the developmental trend of this field has been forecasted.

The 2022 Clean Energy reviewer awards

Energy is crucial for prosperity and development as well as playing a key role in driving innovation.The transition of the world fuel energy mix from fossil fuels towards renewable energy will take time and require innovative technologies.The Clean Energy journal strives to publish high-quality papers on the latest research developments and knowledge on topics related to clean energy.