The unmodified graphitic carbon nitride(g-C_3N_4) suffers from low photocatalytic activity because of the unfavourable structure.In the present work,we reported a simple self-structural modification strategy to optimi...The unmodified graphitic carbon nitride(g-C_3N_4) suffers from low photocatalytic activity because of the unfavourable structure.In the present work,we reported a simple self-structural modification strategy to optimize the microstructure of g-C_3N_4 and obtained graphene-like g-C_3N_4 nanosheets with porous structure.In contrast to traditional thermal pyrolysis preparation of g-C_3N_4,the present thermal condensation was improved via pyrolysis of thiourea in an alumina crucible without a cover,followed by secondary heat treatment.The popcorn-like formation and layer-by-layer thermal exfoliation of graphene-like porous g-C_3N_4 was proposed to explain the formation mechanism.The photocatalytic removal performance of both NO and NO_2 with the graphene-like porous g-C_3N_4 for was significantly enhanced by selfstructural modification.Trapping experiments and in-situ diffuse reflectance infrared fourier transform spectroscopy(DRIFTS) measurement were conducted to detect the active species during photocatalysis and the conversion pathway of g-C_3N_4 photocatalysis for NO_x purification was revealed.The photocatalytic activity of graphene-like porous g-C_3N_4 was highly enhanced due to the improved charge separation and increased oxidation capacity of the ·O_2^- radicals and holes.This work could not only provide a novel self-structural modification for design of highly efficient photocatalysts,but also offer new insights into the mechanistic understanding of g-C_3N_4 photocatalysis.展开更多
Recently,the rational design of non-precious metal electrocatalysts for highly efficient hydrogen evolution reaction(HER)in alkaline media has received considerable interests in sustainable and renewable energy resear...Recently,the rational design of non-precious metal electrocatalysts for highly efficient hydrogen evolution reaction(HER)in alkaline media has received considerable interests in sustainable and renewable energy researches.Herein,vertically aligned and interconnected NiS2/CoS2/MoS2 nanosheet arrays on Ni foam were prepared by a two-step procedure that conducted by the hydrothermal synthesis of NiCo molybdate nanosheet array as the precursor and followed by the vapor phase sulfurization to achieve in situ conversion.Basing on the scanning electron microscopy(SEM)and transmission electron microscopy(TEM)characterizations,it can be found that the honeycomb-like structure of the Ni-Co molybdate nanosheet array was well preserved after the sulfurization process.The high-resolution TEM(HRTEM)characterization reveals that the NiS2/CoS2/MoS2 nanosheet array provided abundant well-exposed active edge sites and multiple heterointerfaces towards enhanced alkaline HER performance.Electrochemical studies demonstrated that the ultrathin NiS2/CoS2/MoS2nanosheets exhibited excellent HER performance with an overpotential of 112 m V at 10 m A cm-2and a smaller Tafel slope of 59 m V dec-1in comparison with NiS2/MoS2(155 mV and 89 mV dec-1)and CoS2/MoS2(124 m V and 75 m V dec-1)samples by taking the advantage of the well-exposed multiple heterointerfaces.This work presents a facile and reliable synthetic strategy for the rational design of highly efficient electrocatalysts for the HER in alkaline solution based on non-precious metal sulfide nanocomposite.展开更多
开发具有多层次结构(包括多孔结构、杂化骨架和/或拓扑形貌)的超结构碳材料,对于满足电化学储能和转换系统中复杂催化反应的需求非常关键.在本文中,我们以钴纳米颗粒为催化位点,在杂化碳纳米管骨架表面可控接枝毛发状碳纳米管,开发了一...开发具有多层次结构(包括多孔结构、杂化骨架和/或拓扑形貌)的超结构碳材料,对于满足电化学储能和转换系统中复杂催化反应的需求非常关键.在本文中,我们以钴纳米颗粒为催化位点,在杂化碳纳米管骨架表面可控接枝毛发状碳纳米管,开发了一类层次化多孔的钴修饰碳纳米管瓶刷(Co/CNTBs).其中,精确的瓶刷状拓扑形貌和分级多孔结构能够有效地提供可及表/界面和高导电网络,钴修饰的杂化骨架可以促进硫的氧化还原反应动力学.因此,基于Co/CNTBs功能化隔膜的锂硫电池具有优异的倍率性能(在10 C下比容量为707 mA h g^(-1))和长效的循环稳定性.更重要的是,基于Co/CNTBs催化剂的高硫载量电池(6.72 mg cm^(-2))在0.1 C下循环100圈后仍具有4.81 mA h cm^(-2)的高面积容量.本工作为高性能超结构杂化碳材料的原位接枝合成策略带来了新的思路,有望用于众多具有挑战性的应用.展开更多
Electrochemical energy conversion technologies involving processes such as water splitting and O_(2)/CO_(2) reduction,provide promising solutions for addressing global energy scarcity and minimizing adverse environmen...Electrochemical energy conversion technologies involving processes such as water splitting and O_(2)/CO_(2) reduction,provide promising solutions for addressing global energy scarcity and minimizing adverse environmental impact.However,due to a lack of an in-depth understanding of the reaction mechanisms and the nature of the active sites,further advancement of these techniques has been limited by the development of efficient and robust catalysts.Therefore,in situ characterization of these electrocatalytic processes under working conditions is essential.In this review,recent applications of in situ Raman spectroscopy and X-ray absorption spectroscopy for various nano-and single-atom catalysts in energy-related reactions are summarized.Notable cases are highlighted,including the capture of oxygen-containing intermediate species formed during the reduction of oxygen and oxidation of hydrogen,and the detection of catalyst structural transformations occurring with the change in potential during the evolution of oxygen and reduction of CO_(2).Finally,the challenges and outlook for advancing in situ spectroscopic technologies to gain a deeper fundamental understanding of these energy-related electrocatalytic processes are discussed.展开更多
Global warming caused by excess carbon dioxide(CO_(2))emission has been a focus of the world.The development of neutral carbon technologies becomes a strategic choice for the sustainable human society.Integrating CO_(...Global warming caused by excess carbon dioxide(CO_(2))emission has been a focus of the world.The development of neutral carbon technologies becomes a strategic choice for the sustainable human society.Integrating CO_(2) capture and conversion(iCCC)technology can simultaneously convert the captured CO_(2) from flue gas into value-added chemicals,which saves great energies and expenses incurred in CO_(2) compression and transportation processes of conventional carbon capture,utilization,and storage(CCUS)technology.The present review criti-cally discusses the dual-function materials(DFMs)and the iCCC technology at intermediate temperature for methane production and high temperature for syngas production.The design of reactor and optimization of operation conditions are emphasized from the perspective of industrial applications.The dual-fixed-bed reactors mode by switching the flue gas and reactant gases,and the dual-fluidized-bed reactors mode by the circulation of DFMs particles are comparatively reviewed.We hope this review can stimulate further studies including designing and fabricating feasible DFMs,exploring realistic catalytic process for CO_(2) conversion to high value-added chemicals,developing workable reactor modes and optimizing operation conditions,and establishing industrial demonstration for real applications of iCCC technology in the future.展开更多
The autothermic pyrolysis in-situ conversion process (ATS) consumes latent heat of residual organic matter after kerogen pyrolysis by oxidation reaction, and it has the advantages of low development cost and exploitat...The autothermic pyrolysis in-situ conversion process (ATS) consumes latent heat of residual organic matter after kerogen pyrolysis by oxidation reaction, and it has the advantages of low development cost and exploitation of deep oil shale resources. However, the heating mechanism and the characteristic of different reaction zones are still unclear. In this study, an ATS numerical simulation model was proposed for the development of oil shale, which considers the pyrolysis of kerogen, high-temperature oxidation, and low-temperature oxidation. Based on the above model, the mechanism of the ATS was analyzed and the effects of preheating temperature, O_(2) content, and injection rate on recovery factor and energy efficiency were studied. The results showed that the ATS in the formation can be divided into five characteristic zones by evolution of the oil and O_(2) distribution, and the solid organic matter, including residue zone, autothermic zone, pyrolysis zone, preheating zone, and original zone. Energy efficiency was much higher for the ATS than for the high-temperature nitrogen injection in-situ conversion process (HNICP). There is a threshold value of the preheating temperature, the oil content, and the injection rate during the ATS, which is 400 °C, 0.18, and 1100 m3/day, respectively, in this study.展开更多
To achieve the goals of carbon peaking and carbon neutrality under the backgrounds of poor resource endowments, weak theoretical basis and other factors, the development of the coalbed methane industry of China faces ...To achieve the goals of carbon peaking and carbon neutrality under the backgrounds of poor resource endowments, weak theoretical basis and other factors, the development of the coalbed methane industry of China faces many bottlenecks and challenges. This paper systematically analyzes the coalbed methane resources, key technologies and progress, exploration effect and production performance in China and abroad. The main problems are summarized as low exploration degree, low technical adaptability, low return on investment and small development scale. This study suggests that the coalbed methane industry in China should follow the “two-step”(short-term and long-term) development strategy. The short-term action before 2030, can be divided into two stages:(1) From the present to 2025, to achieve new breakthroughs in theory and technology, and accomplish the target of annual production of 10 billion cubic meters;(2) From 2025 to 2030, to form the technologies suitable for most geological conditions, further expand the industry scale, and achieve an annual output of 30 billion cubic meters, improving the proportion of coalbed methane in the total natural gas production. The long-term action after 2030 is to gradually realize an annual production of 100 billion cubic meters. The strategic countermeasure to achieve the above goals is to adhere to “technology+management dual wheel drive”, realize the synchronous progress of technology and management, and promote the high-quality development of the coalbed methane industry. Technically, the efforts will focus on fine and effective development of coalbed methane in the medium to shallow layers of mature fields, effective development of coalbed methane in new fields, extensive and beneficial development of deep coalbed methane, three-dimensional comingled development of coalbed methane, applying new technologies such as coalbed methane displacement by carbon dioxide, microwave heating and stimulation technology, ultrasonic stimulation, high-temperature heat injection展开更多
基金supported by the National Natural Science Foundation of China(51478070,21501016 and 21777011)the National Key R&D Program of China(2016YFC0204702)+3 种基金the Innovative Research Team of Chongqing(CXTDG201602014)the Natural Science Foundation of Chongqing(cstc2016jcyj A0481,cstc2017jcyj BX0052)the Early Career Scheme(ECS 809813) from Hong Kongthe Internal Research Grant from Hong Kong Institute of Education(R3588)
文摘The unmodified graphitic carbon nitride(g-C_3N_4) suffers from low photocatalytic activity because of the unfavourable structure.In the present work,we reported a simple self-structural modification strategy to optimize the microstructure of g-C_3N_4 and obtained graphene-like g-C_3N_4 nanosheets with porous structure.In contrast to traditional thermal pyrolysis preparation of g-C_3N_4,the present thermal condensation was improved via pyrolysis of thiourea in an alumina crucible without a cover,followed by secondary heat treatment.The popcorn-like formation and layer-by-layer thermal exfoliation of graphene-like porous g-C_3N_4 was proposed to explain the formation mechanism.The photocatalytic removal performance of both NO and NO_2 with the graphene-like porous g-C_3N_4 for was significantly enhanced by selfstructural modification.Trapping experiments and in-situ diffuse reflectance infrared fourier transform spectroscopy(DRIFTS) measurement were conducted to detect the active species during photocatalysis and the conversion pathway of g-C_3N_4 photocatalysis for NO_x purification was revealed.The photocatalytic activity of graphene-like porous g-C_3N_4 was highly enhanced due to the improved charge separation and increased oxidation capacity of the ·O_2^- radicals and holes.This work could not only provide a novel self-structural modification for design of highly efficient photocatalysts,but also offer new insights into the mechanistic understanding of g-C_3N_4 photocatalysis.
基金supported by the National Natural Science Foundation of China(21603014 and 51872031)the National Key Research and Development Program of China(2016YFA0202703).
文摘Recently,the rational design of non-precious metal electrocatalysts for highly efficient hydrogen evolution reaction(HER)in alkaline media has received considerable interests in sustainable and renewable energy researches.Herein,vertically aligned and interconnected NiS2/CoS2/MoS2 nanosheet arrays on Ni foam were prepared by a two-step procedure that conducted by the hydrothermal synthesis of NiCo molybdate nanosheet array as the precursor and followed by the vapor phase sulfurization to achieve in situ conversion.Basing on the scanning electron microscopy(SEM)and transmission electron microscopy(TEM)characterizations,it can be found that the honeycomb-like structure of the Ni-Co molybdate nanosheet array was well preserved after the sulfurization process.The high-resolution TEM(HRTEM)characterization reveals that the NiS2/CoS2/MoS2 nanosheet array provided abundant well-exposed active edge sites and multiple heterointerfaces towards enhanced alkaline HER performance.Electrochemical studies demonstrated that the ultrathin NiS2/CoS2/MoS2nanosheets exhibited excellent HER performance with an overpotential of 112 m V at 10 m A cm-2and a smaller Tafel slope of 59 m V dec-1in comparison with NiS2/MoS2(155 mV and 89 mV dec-1)and CoS2/MoS2(124 m V and 75 m V dec-1)samples by taking the advantage of the well-exposed multiple heterointerfaces.This work presents a facile and reliable synthetic strategy for the rational design of highly efficient electrocatalysts for the HER in alkaline solution based on non-precious metal sulfide nanocomposite.
基金supported by the National Natural Science Foundation of China(51872336,51925308,and 52172061)the National Key Research and Development Program of China(2021YFF0500600)+3 种基金the Pearl River Talent Plan of Guangdong(2017GC010612)the Natural Science Foundation of Guangdong(2021A1515011617)the Fundamental Research Funds for the Central Universities(20lgzd18)the Science and Technology Program of Guangzhou(202102021111 and 202002020041)。
文摘开发具有多层次结构(包括多孔结构、杂化骨架和/或拓扑形貌)的超结构碳材料,对于满足电化学储能和转换系统中复杂催化反应的需求非常关键.在本文中,我们以钴纳米颗粒为催化位点,在杂化碳纳米管骨架表面可控接枝毛发状碳纳米管,开发了一类层次化多孔的钴修饰碳纳米管瓶刷(Co/CNTBs).其中,精确的瓶刷状拓扑形貌和分级多孔结构能够有效地提供可及表/界面和高导电网络,钴修饰的杂化骨架可以促进硫的氧化还原反应动力学.因此,基于Co/CNTBs功能化隔膜的锂硫电池具有优异的倍率性能(在10 C下比容量为707 mA h g^(-1))和长效的循环稳定性.更重要的是,基于Co/CNTBs催化剂的高硫载量电池(6.72 mg cm^(-2))在0.1 C下循环100圈后仍具有4.81 mA h cm^(-2)的高面积容量.本工作为高性能超结构杂化碳材料的原位接枝合成策略带来了新的思路,有望用于众多具有挑战性的应用.
文摘Electrochemical energy conversion technologies involving processes such as water splitting and O_(2)/CO_(2) reduction,provide promising solutions for addressing global energy scarcity and minimizing adverse environmental impact.However,due to a lack of an in-depth understanding of the reaction mechanisms and the nature of the active sites,further advancement of these techniques has been limited by the development of efficient and robust catalysts.Therefore,in situ characterization of these electrocatalytic processes under working conditions is essential.In this review,recent applications of in situ Raman spectroscopy and X-ray absorption spectroscopy for various nano-and single-atom catalysts in energy-related reactions are summarized.Notable cases are highlighted,including the capture of oxygen-containing intermediate species formed during the reduction of oxygen and oxidation of hydrogen,and the detection of catalyst structural transformations occurring with the change in potential during the evolution of oxygen and reduction of CO_(2).Finally,the challenges and outlook for advancing in situ spectroscopic technologies to gain a deeper fundamental understanding of these energy-related electrocatalytic processes are discussed.
基金The authors are grateful to the financial support from Shanghai Science and Technology Committee(No.19160712100)National Natural Science Foundation of China(No.21878076).
文摘Global warming caused by excess carbon dioxide(CO_(2))emission has been a focus of the world.The development of neutral carbon technologies becomes a strategic choice for the sustainable human society.Integrating CO_(2) capture and conversion(iCCC)technology can simultaneously convert the captured CO_(2) from flue gas into value-added chemicals,which saves great energies and expenses incurred in CO_(2) compression and transportation processes of conventional carbon capture,utilization,and storage(CCUS)technology.The present review criti-cally discusses the dual-function materials(DFMs)and the iCCC technology at intermediate temperature for methane production and high temperature for syngas production.The design of reactor and optimization of operation conditions are emphasized from the perspective of industrial applications.The dual-fixed-bed reactors mode by switching the flue gas and reactant gases,and the dual-fluidized-bed reactors mode by the circulation of DFMs particles are comparatively reviewed.We hope this review can stimulate further studies including designing and fabricating feasible DFMs,exploring realistic catalytic process for CO_(2) conversion to high value-added chemicals,developing workable reactor modes and optimizing operation conditions,and establishing industrial demonstration for real applications of iCCC technology in the future.
基金financial support offered by the National Key R&D Program of China(Grant No.2019YFA0705502,Grant No.2019YFA0705501)the National Natural Science Fund Project of China(Grant No.4210020395)+1 种基金the China Postdoctoral Science Foundation(Grant No.2021M700053)Technology Development Plan Project of Jilin Province(Grant No.20200201219JC).
文摘The autothermic pyrolysis in-situ conversion process (ATS) consumes latent heat of residual organic matter after kerogen pyrolysis by oxidation reaction, and it has the advantages of low development cost and exploitation of deep oil shale resources. However, the heating mechanism and the characteristic of different reaction zones are still unclear. In this study, an ATS numerical simulation model was proposed for the development of oil shale, which considers the pyrolysis of kerogen, high-temperature oxidation, and low-temperature oxidation. Based on the above model, the mechanism of the ATS was analyzed and the effects of preheating temperature, O_(2) content, and injection rate on recovery factor and energy efficiency were studied. The results showed that the ATS in the formation can be divided into five characteristic zones by evolution of the oil and O_(2) distribution, and the solid organic matter, including residue zone, autothermic zone, pyrolysis zone, preheating zone, and original zone. Energy efficiency was much higher for the ATS than for the high-temperature nitrogen injection in-situ conversion process (HNICP). There is a threshold value of the preheating temperature, the oil content, and the injection rate during the ATS, which is 400 °C, 0.18, and 1100 m3/day, respectively, in this study.
基金Supported by the China National Science and Technology Major Project (2016ZX05042)。
文摘To achieve the goals of carbon peaking and carbon neutrality under the backgrounds of poor resource endowments, weak theoretical basis and other factors, the development of the coalbed methane industry of China faces many bottlenecks and challenges. This paper systematically analyzes the coalbed methane resources, key technologies and progress, exploration effect and production performance in China and abroad. The main problems are summarized as low exploration degree, low technical adaptability, low return on investment and small development scale. This study suggests that the coalbed methane industry in China should follow the “two-step”(short-term and long-term) development strategy. The short-term action before 2030, can be divided into two stages:(1) From the present to 2025, to achieve new breakthroughs in theory and technology, and accomplish the target of annual production of 10 billion cubic meters;(2) From 2025 to 2030, to form the technologies suitable for most geological conditions, further expand the industry scale, and achieve an annual output of 30 billion cubic meters, improving the proportion of coalbed methane in the total natural gas production. The long-term action after 2030 is to gradually realize an annual production of 100 billion cubic meters. The strategic countermeasure to achieve the above goals is to adhere to “technology+management dual wheel drive”, realize the synchronous progress of technology and management, and promote the high-quality development of the coalbed methane industry. Technically, the efforts will focus on fine and effective development of coalbed methane in the medium to shallow layers of mature fields, effective development of coalbed methane in new fields, extensive and beneficial development of deep coalbed methane, three-dimensional comingled development of coalbed methane, applying new technologies such as coalbed methane displacement by carbon dioxide, microwave heating and stimulation technology, ultrasonic stimulation, high-temperature heat injection
