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Wu Y, Yang W, Zhang H, Xu H, Jiao Y, Zhong L, Wang J, Chen Y. Boosting Methane Combustion over Pd/Y 2O 3-ZrO 2 Catalyst by Inert Silicate Patches Tuning Both Palladium Chemistry and Support Hydrophobicity. ACS APPLIED MATERIALS & INTERFACES 2023; 15:44887-44898. [PMID: 37721481 DOI: 10.1021/acsami.3c08087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Supported palladium (Pd) catalysts are widely utilized to reduce the emission of exhaust CH4 from lean-burn engines by catalytic combustion. A large amount of water vapor in the exhaust makes hydroxyls accumulate on the catalyst surface at temperatures below 450 °C, leading to severe catalyst deactivation. Tuning palladium chemistry and inhibiting water adsorption are critical to developing active catalysts. Modifying the support surface with inert silicates would both change the palladium-support interaction and decrease water adsorption sites. This study reports an improved Pd/Y2O3-ZrO2 catalyst by constructing silicate patches on yttria-stabilized zirconia (Y2O3-ZrO2) support. The silicates hindered electron transfer from Y2O3-ZrO2 oxygen vacancies to palladium, which optimized palladium chemistry, especially the reducibility of active PdO species, and thereby boosted CH4 conversion under dry conditions. The temperature of 90% methane conversion (T90) over the catalyst decreased from 386 to 309 °C. Moreover, the inert silicates decreased surface oxygen vacancies of Y2O3-ZrO2 to improve support hydrophobicity, thereby inhibiting hydroxyl accumulation. The poisoning effect of water on the active sites located on the palladium-silicate interface was alleviated. When reaction gases contained 10 vol % water, the silicate-modified catalyst still showed higher activity with T90 of 404 °C, which is lower than T90 of 452 °C for unmodified catalyst. This work represents a step forward in preparing high-performance palladium catalysts for low-temperature wet methane combustion.
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Affiliation(s)
- Yang Wu
- Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, China
| | - Wenhu Yang
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610065, China
| | - Hailong Zhang
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610065, China
| | - Haidi Xu
- Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, China
| | - Yi Jiao
- Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, China
| | - Lin Zhong
- College of Chemical Engineering, Sichuan University, Chengdu 610065, China
| | - Jianli Wang
- Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, China
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610065, China
| | - Yaoqiang Chen
- Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, China
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610065, China
- College of Chemical Engineering, Sichuan University, Chengdu 610065, China
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Yasumura S, Saita K, Miyakage T, Nagai K, Kon K, Toyao T, Maeno Z, Taketsugu T, Shimizu KI. Designing main-group catalysts for low-temperature methane combustion by ozone. Nat Commun 2023; 14:3926. [PMID: 37400448 DOI: 10.1038/s41467-023-39541-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 06/16/2023] [Indexed: 07/05/2023] Open
Abstract
The catalytic combustion of methane at a low temperature is becoming increasingly key to controlling unburned CH4 emissions from natural gas vehicles and power plants, although the low activity of benchmark platinum-group-metal catalysts hinders its broad application. Based on automated reaction route mapping, we explore main-group elements catalysts containing Si and Al for low-temperature CH4 combustion with ozone. Computational screening of the active site predicts that strong Brønsted acid sites are promising for methane combustion. We experimentally demonstrate that catalysts containing strong Bronsted acid sites exhibit improved CH4 conversion at 250 °C, correlating with the theoretical predictions. The main-group catalyst (proton-type beta zeolite) delivered a reaction rate that is 442 times higher than that of a benchmark catalyst (5 wt% Pd-loaded Al2O3) at 190 °C and exhibits higher tolerance to steam and SO2. Our strategy demonstrates the rational design of earth-abundant catalysts based on automated reaction route mapping.
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Affiliation(s)
- Shunsaku Yasumura
- Institute for Catalysis, Hokkaido University, N-21 W-10, Sapporo, Hokkaido, 001-0021, Japan
| | - Kenichiro Saita
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
| | - Takumi Miyakage
- Institute for Catalysis, Hokkaido University, N-21 W-10, Sapporo, Hokkaido, 001-0021, Japan
| | - Ken Nagai
- Institute for Catalysis, Hokkaido University, N-21 W-10, Sapporo, Hokkaido, 001-0021, Japan
| | - Kenichi Kon
- Institute for Catalysis, Hokkaido University, N-21 W-10, Sapporo, Hokkaido, 001-0021, Japan
| | - Takashi Toyao
- Institute for Catalysis, Hokkaido University, N-21 W-10, Sapporo, Hokkaido, 001-0021, Japan
| | - Zen Maeno
- School of Advanced Engineering, Kogakuin University, Tokyo, 192-0015, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo, Hokkaido, 001-0021, Japan
| | - Ken-Ichi Shimizu
- Institute for Catalysis, Hokkaido University, N-21 W-10, Sapporo, Hokkaido, 001-0021, Japan.
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Effects of Ignition Timing on Combustion Characteristics of a Gasoline Direct Injection Engine with Added Compressed Natural Gas under Partial Load Conditions. Processes (Basel) 2021. [DOI: 10.3390/pr9050755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The gasoline/natural gas dual-fuel combustion mode has been found to have unique advantages in combustion. The ignition timing has a significant impact on the combustion characteristics of gasoline engines. Thus, here we study the combustion characteristics of gasoline/natural gas dual-fuel combustion mode to determine the details of their respective advantages under cooperative combustion. A direct-injection turbocharged gasoline engine was modified, and an engine experimental platform was built for the coordinated control of gasoline direct-injection and natural gas port injection. A low-speed and low-load operating point was selected, and the in-cylinder pressure, heat release rate, pressure rise rate, combustion temperature, ignition delay, and combustion duration under the coordinated combustion of gasoline and natural gas dual fuel at the ignition moment were studied through bench tests among other typical combustion parameters. The results show that with the increase of the ignition advance angle, the maximum cylinder pressure, heat release rate, pressure rise rate, and maximum combustion temperature increase. The ignition advance angle is 28°CA-BTDC, and PES40 has the best fuel synergy effect and the best power performance improvement. The effect of the advance of the ignition advance angle on the ignition delay and the combustion duration reaches the peak at 20°CA-BTDC–22°CA-BTDC, and the improvement of the two periods is more significant at PES60.
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Fundamentals of Sulfate Species in Methane Combustion Catalyst Operation and Regeneration—A Simulated Exhaust Gas Study. Catalysts 2019. [DOI: 10.3390/catal9050417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Emission regulations and legislation inside the European Union (EU) have a target to reduce tailpipe emissions in the transportation sector. Exhaust gas aftertreatment systems play a key role in low emission vehicles, particularly when natural gas or bio-methane is used as the fuel. The main question for methane operating vehicles is the durability of the palladium-rich aftertreatment system. To improve the durability of the catalysts, a regeneration method involving an efficient removal of sulfur species needs to be developed and implemented on the vehicle. This paper tackles the topic and its issues from a fundamental point of view. This study showed that Al2(SO4)3 over Al2O3 support material inhibits re-oxidation of Pd to PdO, and thus hinders the formation of the low-temperature active phase, PdOx. The presence of Al2(SO4)3 increases light-off temperature, which may be due to a blocking of active sites. Overall, this study showed that research should also focus on support material development, not only active phase inspection. An active catalyst can always be developed, but the catalyst should have the ability to be regenerated.
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