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Xu D, Huang Q, Xu X, Sang X. NiMOF-derived oxygen vacancy rich NiO with excellent capacitance and ORR/OER activities as a cathode material for Zn-based hybrid batteries. Dalton Trans 2020; 49:12441-12449. [PMID: 32852016 DOI: 10.1039/d0dt01153c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An Ni-Zn battery is a distinguished member in the family of closed Zn-based batteries due to its ideal power density and voltage. However, when it is employed as a power supply for electric vehicles, its defects in terms of specific capacitance and energy density become obvious. Herein, to resolve this problem, a hybrid battery system was created through a combination of Ni-Zn and Zn-air batteries at the cell level. In a hybrid battery system, oxygen vacancy rich NiO with S,N co-modified mesoporous carbon as a matrix was used as the cathode material. This cathode material showed a high specific capacitance of 202.1 mA h g-1 at 1.0 A g-1. When the current density reduces to 20 A g-1, this value decreases to 130.2 mA h g-1, which implies that 64.4% of specific capacitance was retained. It also exhibits excellent OER and ORR activities. For the hybrid battery system, when the discharge process was carried out at 1 mA cm-2, there were two voltage plateaus at 1.72 and 1.12 V, which originated from Ni-Zn and Zn-air, respectively. In this case, its specific capacitance and energy density reaches 800.3 mA h g-1 and 961 W h kg-1, respectively. The hybrid battery also possesses perfect stability during multi-cycle charge-discharge tests. The construction of this hybrid battery system develops a new road to prepare a power supply device with high performance.
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Affiliation(s)
- Dandan Xu
- Department of Chemistry, College of Science, Northeastern University, Shenyang, 110819, P.R. China.
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Da Pan, Tao L, Sun K, Golston LM, Miller DJ, Zhu T, Qin Y, Zhang Y, Mauzerall DL, Zondlo MA. Methane emissions from natural gas vehicles in China. Nat Commun 2020; 11:4588. [PMID: 32917876 PMCID: PMC7486943 DOI: 10.1038/s41467-020-18141-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 07/10/2020] [Indexed: 11/09/2022] Open
Abstract
Natural gas vehicles (NGVs) have been promoted in China to mitigate air pollution, yet our measurements and analyses show that NGV growth in China may have significant negative impacts on climate change. We conducted real-world vehicle emission measurements in China and found high methane emissions from heavy-duty NGVs (90% higher than current emission limits). These emissions have been ignored in previous emission estimates, leading to biased results. Applying our observations to life-cycle analyses, we found that switching to NGVs from conventional vehicles in China has led to a net increase in greenhouse gas (GHG) emissions since 2000. With scenario analyses, we also show that the next decade will be critical for China to reverse the trend with the upcoming China VI standard for heavy-duty vehicles. Implementing and enforcing the China VI standard is challenging, and the method demonstrated here can provide critical information regarding the fleet-level CH4 emissions from NGVs.
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Affiliation(s)
- Da Pan
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA. .,Center for Mid-Infrared Technologies for Health and The Environmental, NSF-ERC, Princeton, NJ, 08544, USA.
| | - Lei Tao
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA.,Center for Mid-Infrared Technologies for Health and The Environmental, NSF-ERC, Princeton, NJ, 08544, USA
| | - Kang Sun
- Department of Civil, Structural and Environmental Engineering, University at Buffalo, Buffalo, NY, 14260, USA.,Research and Education in eNergy, Environment and Water (RENEW) Institute, University at Buffalo, Buffalo, NY, 14260, USA
| | - Levi M Golston
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA.,Center for Mid-Infrared Technologies for Health and The Environmental, NSF-ERC, Princeton, NJ, 08544, USA
| | - David J Miller
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA.,Center for Mid-Infrared Technologies for Health and The Environmental, NSF-ERC, Princeton, NJ, 08544, USA.,Currently at Environmental Defense Fund, New York, NY, 10010, USA
| | - Tong Zhu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, 100871, Beijing, China
| | - Yue Qin
- Department of Geography, The Ohio State University, Columbus, OH, 43210, USA.,Sustainability Institute, The Ohio State University, Columbus, OH, 43210, USA
| | - Yan Zhang
- Department of Geography, Environment, and Spatial Sciences, Michigan State University, East Lansing, MI, 48824, USA
| | - Denise L Mauzerall
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA.,Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, NJ, 08544, USA
| | - Mark A Zondlo
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA. .,Center for Mid-Infrared Technologies for Health and The Environmental, NSF-ERC, Princeton, NJ, 08544, USA.
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Habib G. Chemical and optical properties of PM 2.5 from on-road operation of light duty vehicles in Delhi city. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 586:900-916. [PMID: 28238373 DOI: 10.1016/j.scitotenv.2017.02.070] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 01/26/2017] [Accepted: 02/08/2017] [Indexed: 06/06/2023]
Abstract
This study reports emission factors of PM2.5, elemental carbon (EC), organic carbon (OC), ions, trace elements and mass absorption cross-sections (MAC) of aerosol emitted from the on-road operation of light duty vehicles of different vintages. A portable dilution system was used to achieve complete quenching of aerosol at near ambient condition. The particles were collected on the filters and analyzed for chemical and light absorbing properties of aerosol. The diesel-powered passenger cars emitted higher PM2.5 (56-356mgkm-1) with a large fraction of EC (37-65%), while emissions from gasoline (46-78mgkm-1), and CNG vehicles (33-34mgkm-1) were low and contained low EC (5-15%) and remarkably high OC (46-91%). The MAC of aerosols for diesel vehicles (32-208m2g-1 of PM2.5) were well explained by EC content (31-62%) and showed similarity with MAC values reported for wood fuel combustion in cooking stoves indicating the two sources cannot be resolved on the basis of light absorption properties in source apportionment studies. Ionic contributions to PM2.5 were highest for 4W-gasoline (11-19%) compared to 4W-diesel (7-11%), and CNG (9-10%). The abundance of ions such as Na+, Ca2+, SO42-, NO3-, and NH4+ could be due to use of lubricant oil and abrasive nature of engine of old vehicles. Trace elements (Al, Fe, Zn, Pb, and Cu) emitted from after-treatment devices, additives in lube oil, and wearing of engine components, were found to be 2-14%, 3-8% and 11-12% of total PM2.5 for 4W of diesel, gasoline, and CNG respectively. This study indicates that aerosol emissions from on-road vehicles show a strong dependency on vehicle maintenance, engine type and after-treatment techniques.
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Wadud Z, Khan T. Air quality and climate impacts due to CNG conversion of motor vehicles in Dhaka, Bangladesh. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:13907-13916. [PMID: 24195736 DOI: 10.1021/es402338b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Dhaka had recently experienced rapid conversion of its motor vehicle fleet to run on compressed natural gas (CNG). This paper quantifies ex-post the air quality and climate benefits of the CNG conversion policy, including monetary valuations, through an impact pathway approach. Around 2045 (1665) avoided premature deaths in greater Dhaka (City Corporation) can be attributed to air quality improvements from the CNG conversion policy in 2010, resulting in a saving of around USD 400 million. Majority of these health benefits resulted from the conversion of high-emitting diesel vehicles. CNG conversion was clearly detrimental from climate change perspective using the changes in CO2 and CH4 only (CH4 emissions increased); however, after considering other global pollutants (especially black carbon), the climate impact was ambiguous. Uncertainty assessment using input distributions and Monte Carlo simulation along with a sensitivity analysis show that large uncertainties remain for climate impacts. For our most likely estimate, there were some climate costs, valued at USD 17.7 million, which is an order of magnitude smaller than the air quality benefits. This indicates that such policies can and should be undertaken on the grounds of improving local air pollution alone and that precautions should be taken to reduce the potentially unintended increases in GHG emissions or other unintended effects.
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Affiliation(s)
- Zia Wadud
- Centre for Integrated Energy Research, University of Leeds , Leeds LS2 9JT, U.K
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