Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal ...Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal target volume (ITV) definitions with 4D CT. Methods: Fourteen patients with primary and metastatic lung cancer underwent SBRT were enrolled. Full and partial arc VMAT plans were generated with four different ITVs: ITVall, ITVMIP, ITVAIP and ITV2phases, representing ITVs generated from all 10 respiratory phases, maximum intensity projection (MIP), average intensity projection (AIP), and 2 extreme respiratory phases. Volumetric and dosimetric differences, as well as MU and delivery time were investigated. Results: Partial arc VMAT irradiated more dose at 2 cm away from planning target volume (PTV) (P = 0.002), however, it achieved better protection on mean lung dose , lung V5, spinal cord, heart and esophagus compared with full arc VMAT. The average MU and delivery time of partial arc VMAT were 240 and 1.6 min less than those of full arc VMAT. There were no significant differences on target coverage and organ at risks (OARs) sparing among four ITVs. The average percent volume differences of ITVMIP, ITVAIP and ITV2phases to ITVall were 8.6%, 13.4%, and 25.2%, respectively. Conclusions: Although partial arc VMAT delivered more dose 2 cm out of PTV, it decreases the dose to lung, spinal cord, and esophagus, as well decreased the total MU and delivery time compared with full arc VMAT without sacrificing target coverage. Partial arc VMAT was feasible and more efficient for lung SBRT.展开更多
Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4...Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.展开更多
通过电解水制备氢气是实现“碳中和”目标的理想途径之一.因此,可在全p H条件下使用的氢析出(HER)催化剂的研发是近年来电催化领域的研究热点.原子级分散的催化剂,能够在保留铂族金属(PGM)固有活性的同时,降低催化剂中PGM的用量.虽然可...通过电解水制备氢气是实现“碳中和”目标的理想途径之一.因此,可在全p H条件下使用的氢析出(HER)催化剂的研发是近年来电催化领域的研究热点.原子级分散的催化剂,能够在保留铂族金属(PGM)固有活性的同时,降低催化剂中PGM的用量.虽然可以通过X射线吸收光谱(XAS)来表征原子分散的PGM电催化剂的配位环境,但目前对原子空间分布的控制仍然具有挑战.本文制备了钒掺杂钨青铜内通道氨配位的钌单原子催化剂(Ru/V-NHWO),用于全p H范围内的HER反应.采用X射线衍射(XRD)、高角环形暗场扫描透射电镜(HAADF-STEM)、X射线光电子能谱(XPS)和原位X射线吸收光谱(XAS)等进行表征,研究了钌单原子与V-NHWO载体的结合方式以及构效关系,并采用密度泛函理论(DFT)计算探索了催化剂中诸多位点的活性贡献.在1 mol/LKOH, 0.5 mol/L H_(2)SO_(4)和1 mol/L磷酸盐缓冲溶液中,其在10 m Acm^(-2)下的过电位分别为28.0, 29.6和40.6 m V.同时,在过电位100 m V时,质量活性分别达到3930, 1941和602.8 m Amg^(-1)Ru,数倍于同等条件下的商业铂碳.XRD结果表明,钌的引入可以确保催化剂在氩气条件下热解后仍保持六方钨铵青铜晶相,证明钌与钨铵青铜六方晶体通道内氨物种,即“通道氨”的结合.HAADF-STEM结果表明,钌原子与NHWO间存在强烈相互作用,有助于提升HER性能.XPS和XAS结果表明, W5+信号出现在引入钌后,峰位置的结合能增加且峰面积降低,说明钌与通道氨之间存在相互作用.N的XPS结果表明,钌的引入导致了金属氨键的形成.XAS结果表明, Ru/V-NHWO/CC中钌单原子和钌团簇共存,钌单原子与通道氨配位,并且钒的引入会诱发V-NHWO中金属键长缩短,这表明催化剂的金属性得到了提升,有利于改善其导电性.采用DFT计算进一步研究了HER活性的来源.相比于V-NHWO载体和钌团簇修饰的V-NHWO,以单原子形式结合的钌具有更低的水解离能垒,该能垒在氨桥接的钌双原子垂直插入、钒掺杂和多通道插入等多种因素作用下进一步降低.同时,氢中间体结合能得到了相应的优化而趋近于0 e V.此外,差分电荷密度模拟结果表明,氢中间体结合后, V-NHWO对于钌单原子存在明显的供电子行为,有利于HER动力学过程.综上,本工作报道了金属载体对于高分散金属原子空间分布调控的重要作用,可为设计和构筑可应用于诸多能源转换过程的新型原子级分散催化剂提供参考.展开更多
Carbon dioxide emissions have increased due to the consumption of fossil fuels,making the neutralization and utilization of CO_(2) a pressing issue.As a clean and efficient energy conversion process,electrocatalytic r...Carbon dioxide emissions have increased due to the consumption of fossil fuels,making the neutralization and utilization of CO_(2) a pressing issue.As a clean and efficient energy conversion process,electrocatalytic reduction can reduce carbon dioxide into a series of alcohols and acidic organic molecules,which can effectively realize the utilization and transformation of carbon dioxide.This review focuses on the tuning strategies and structure effects of catalysts for the electrocatalytic CO_(2) reduction reaction(CO_(2)RR).The tuning strategies for the active sites of catalysts have been reviewed from intrinsic and external perspectives.The structure effects for the CO_(2)RR catalysts have also been discussed,such as tandem catalysis,synergistic effects and confinement catalysis.We expect that this review about tuning strategies and structure effects can provide guidance for designing highly efficient CO_(2)RR electrocatalysts.展开更多
Shape- and composition-controlled synthesis of platinum-based nanocrystals （NCs） is critical for the development of electrocatalysts that have high activity toward the methanol oxidation reaction （MOR） in direct m...Shape- and composition-controlled synthesis of platinum-based nanocrystals （NCs） is critical for the development of electrocatalysts that have high activity toward the methanol oxidation reaction （MOR） in direct methanol fuel cells （DMFCs）. We report one-pot surfactant-free synthesis of interconnected PtgsCo5 nanowires （NWs） via an oriented attachment process, which has distinct advantages over conventional template- and surfactant-assisted approaches. Enhanced electrochemical activities toward MOR were confirmed through comparison with pure Pt NWs and commercial Pt/C catalyst. Pt95Co5 NWs demonstrated the highest current density during the long-term stability test. These results reveal that the introduction of the 3d-transition metal Co can reduce the catalyst cost and contribute to the improvement of electrochemical performance. The integrated design of interconnected NW structure, bimetallic composition, and clean surfaces in the present system may open a new way to the development of excellent electrocatalysts in DMFCs.展开更多
The discovery of single-atom catalysts(SACs)represents a groundbreaking advancement in the field of catalysis over the past decades.With the in-depth exploration of relevant structure-activity relationships,the metal−...The discovery of single-atom catalysts(SACs)represents a groundbreaking advancement in the field of catalysis over the past decades.With the in-depth exploration of relevant structure-activity relationships,the metal−support interaction(MSI)is widely adopted to elucidate variations in electronic structure and coordination configuration of atomic active sites on various kinds of supports.Herein,we briefly summarize the metal oxide supports for SACs fabrication,including the distinctive characteristics of metal oxide supports,enlightening advancements in metal oxide support-based SACs(MO-SACs),feasible preparation methods for MO-SACs and effective regulation strategies of MSI effect in MO-SACs.In addition,we present our viewpoints and outlook in this field to stimulate rational design and construction of novel MO-SACs applied in diverse renewable energy devices,while some universal suggestions are sincerely given to provoke thoughtful considerations during the research process.展开更多
Scanning electrochemical microscopy(SECM)is a scanning probe technology based on Faraday current changes when an ultramicroelectrode is moved across a sample surface,which can directly reflect the surface topography a...Scanning electrochemical microscopy(SECM)is a scanning probe technology based on Faraday current changes when an ultramicroelectrode is moved across a sample surface,which can directly reflect the surface topography and electrochemical information on the sample through imaging.This Review briefly introduces the basic SECM,including its developmental history and working mode.The application of SECM imaging in energy catalysis is mainly introduced,and the development trend of SECM is described briefly.展开更多
文摘Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal target volume (ITV) definitions with 4D CT. Methods: Fourteen patients with primary and metastatic lung cancer underwent SBRT were enrolled. Full and partial arc VMAT plans were generated with four different ITVs: ITVall, ITVMIP, ITVAIP and ITV2phases, representing ITVs generated from all 10 respiratory phases, maximum intensity projection (MIP), average intensity projection (AIP), and 2 extreme respiratory phases. Volumetric and dosimetric differences, as well as MU and delivery time were investigated. Results: Partial arc VMAT irradiated more dose at 2 cm away from planning target volume (PTV) (P = 0.002), however, it achieved better protection on mean lung dose , lung V5, spinal cord, heart and esophagus compared with full arc VMAT. The average MU and delivery time of partial arc VMAT were 240 and 1.6 min less than those of full arc VMAT. There were no significant differences on target coverage and organ at risks (OARs) sparing among four ITVs. The average percent volume differences of ITVMIP, ITVAIP and ITV2phases to ITVall were 8.6%, 13.4%, and 25.2%, respectively. Conclusions: Although partial arc VMAT delivered more dose 2 cm out of PTV, it decreases the dose to lung, spinal cord, and esophagus, as well decreased the total MU and delivery time compared with full arc VMAT without sacrificing target coverage. Partial arc VMAT was feasible and more efficient for lung SBRT.
基金the financial support from the Key Research and Development Program sponsored by the Ministry of Science and Technology(MOST)(2022YFB4002000,2022YFA1203400)the National Natural Science Foundation of China(22102172,22072145,22372155,22005294,21925205,21721003)。
文摘Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.
文摘通过电解水制备氢气是实现“碳中和”目标的理想途径之一.因此,可在全p H条件下使用的氢析出(HER)催化剂的研发是近年来电催化领域的研究热点.原子级分散的催化剂,能够在保留铂族金属(PGM)固有活性的同时,降低催化剂中PGM的用量.虽然可以通过X射线吸收光谱(XAS)来表征原子分散的PGM电催化剂的配位环境,但目前对原子空间分布的控制仍然具有挑战.本文制备了钒掺杂钨青铜内通道氨配位的钌单原子催化剂(Ru/V-NHWO),用于全p H范围内的HER反应.采用X射线衍射(XRD)、高角环形暗场扫描透射电镜(HAADF-STEM)、X射线光电子能谱(XPS)和原位X射线吸收光谱(XAS)等进行表征,研究了钌单原子与V-NHWO载体的结合方式以及构效关系,并采用密度泛函理论(DFT)计算探索了催化剂中诸多位点的活性贡献.在1 mol/LKOH, 0.5 mol/L H_(2)SO_(4)和1 mol/L磷酸盐缓冲溶液中,其在10 m Acm^(-2)下的过电位分别为28.0, 29.6和40.6 m V.同时,在过电位100 m V时,质量活性分别达到3930, 1941和602.8 m Amg^(-1)Ru,数倍于同等条件下的商业铂碳.XRD结果表明,钌的引入可以确保催化剂在氩气条件下热解后仍保持六方钨铵青铜晶相,证明钌与钨铵青铜六方晶体通道内氨物种,即“通道氨”的结合.HAADF-STEM结果表明,钌原子与NHWO间存在强烈相互作用,有助于提升HER性能.XPS和XAS结果表明, W5+信号出现在引入钌后,峰位置的结合能增加且峰面积降低,说明钌与通道氨之间存在相互作用.N的XPS结果表明,钌的引入导致了金属氨键的形成.XAS结果表明, Ru/V-NHWO/CC中钌单原子和钌团簇共存,钌单原子与通道氨配位,并且钒的引入会诱发V-NHWO中金属键长缩短,这表明催化剂的金属性得到了提升,有利于改善其导电性.采用DFT计算进一步研究了HER活性的来源.相比于V-NHWO载体和钌团簇修饰的V-NHWO,以单原子形式结合的钌具有更低的水解离能垒,该能垒在氨桥接的钌双原子垂直插入、钒掺杂和多通道插入等多种因素作用下进一步降低.同时,氢中间体结合能得到了相应的优化而趋近于0 e V.此外,差分电荷密度模拟结果表明,氢中间体结合后, V-NHWO对于钌单原子存在明显的供电子行为,有利于HER动力学过程.综上,本工作报道了金属载体对于高分散金属原子空间分布调控的重要作用,可为设计和构筑可应用于诸多能源转换过程的新型原子级分散催化剂提供参考.
文摘Carbon dioxide emissions have increased due to the consumption of fossil fuels,making the neutralization and utilization of CO_(2) a pressing issue.As a clean and efficient energy conversion process,electrocatalytic reduction can reduce carbon dioxide into a series of alcohols and acidic organic molecules,which can effectively realize the utilization and transformation of carbon dioxide.This review focuses on the tuning strategies and structure effects of catalysts for the electrocatalytic CO_(2) reduction reaction(CO_(2)RR).The tuning strategies for the active sites of catalysts have been reviewed from intrinsic and external perspectives.The structure effects for the CO_(2)RR catalysts have also been discussed,such as tandem catalysis,synergistic effects and confinement catalysis.We expect that this review about tuning strategies and structure effects can provide guidance for designing highly efficient CO_(2)RR electrocatalysts.
基金The authors gratefully acknowledge the finandal support from the National Natural Science Foundation of China （Nos. 21435005 and 21627808）, the Development Project of Science and Technology of Jilin Province （No. 20170101195JC）, and Key Research Program of Frontier Sciences, Chinese Academy of Sciences （No. QYZDY-SSW-SLH019）.
文摘Shape- and composition-controlled synthesis of platinum-based nanocrystals （NCs） is critical for the development of electrocatalysts that have high activity toward the methanol oxidation reaction （MOR） in direct methanol fuel cells （DMFCs）. We report one-pot surfactant-free synthesis of interconnected PtgsCo5 nanowires （NWs） via an oriented attachment process, which has distinct advantages over conventional template- and surfactant-assisted approaches. Enhanced electrochemical activities toward MOR were confirmed through comparison with pure Pt NWs and commercial Pt/C catalyst. Pt95Co5 NWs demonstrated the highest current density during the long-term stability test. These results reveal that the introduction of the 3d-transition metal Co can reduce the catalyst cost and contribute to the improvement of electrochemical performance. The integrated design of interconnected NW structure, bimetallic composition, and clean surfaces in the present system may open a new way to the development of excellent electrocatalysts in DMFCs.
基金The authors are grateful to the financial support from the Key Research and Development Program sponsored by the Ministry of Science and Technology(MOST)(2022YFA1203400)the National Natural Science Foundation of China(22102172,22372155,22072145,22005294,21925205,21721003)the authors also thank the ZEROVISION company for providing assistance in creating figures for this manuscript.
文摘The discovery of single-atom catalysts(SACs)represents a groundbreaking advancement in the field of catalysis over the past decades.With the in-depth exploration of relevant structure-activity relationships,the metal−support interaction(MSI)is widely adopted to elucidate variations in electronic structure and coordination configuration of atomic active sites on various kinds of supports.Herein,we briefly summarize the metal oxide supports for SACs fabrication,including the distinctive characteristics of metal oxide supports,enlightening advancements in metal oxide support-based SACs(MO-SACs),feasible preparation methods for MO-SACs and effective regulation strategies of MSI effect in MO-SACs.In addition,we present our viewpoints and outlook in this field to stimulate rational design and construction of novel MO-SACs applied in diverse renewable energy devices,while some universal suggestions are sincerely given to provoke thoughtful considerations during the research process.
基金the financial support from the by the National Natural Science Foundation of China(Nos.21721003,22102172,22072145,22005294,and 21925205).
文摘Scanning electrochemical microscopy(SECM)is a scanning probe technology based on Faraday current changes when an ultramicroelectrode is moved across a sample surface,which can directly reflect the surface topography and electrochemical information on the sample through imaging.This Review briefly introduces the basic SECM,including its developmental history and working mode.The application of SECM imaging in energy catalysis is mainly introduced,and the development trend of SECM is described briefly.
