Precise catalysis is critical for the high-quality catalysis industry.However,it remains challenging to fundamentally understand precise catalysis at the atomic orbital level.Herein,we propose a new strategy to unrave...Precise catalysis is critical for the high-quality catalysis industry.However,it remains challenging to fundamentally understand precise catalysis at the atomic orbital level.Herein,we propose a new strategy to unravel the role of specific d orbitals in catalysis.The oxygen reduction reaction(ORR)catalyzed by atomically dispersed Pt/Co-doped Ti_(1−x)O_(2) nanosheets(Pt_(1)/Co_(1)-Ti_(1−x)O_(2))is used as a model catalysis.The z-axis d orbitals of Pt/Co-Ti realms dominate the O2 adsorption,thus triggering ORR.In light of orbital-resolved analysis,Pt_(1)/Co_(1)-Ti_(1−x)O_(2) is experimentally fabricated,and the excellent ORR catalytic performance is further demonstrated.Further analysis reveals that the superior ORR performance of Pt_(1)-Ti_(1−x)O_(2) to Co_(1)-Ti_(1−x)O_(2) is ascribed to stronger activation of Ti by Pt than Co via the d-d hybridization.Overall,this work provides a useful tool to understand the underlying catalytic mechanisms at the atomic orbital level and opens new opportunities for precise catalyst design.展开更多
Co-doped ZnO nanoparticles are synthesized by co-precipitation method. The incorporation of Co ions into ZnO wur- zite structure with increasing Co concentrations was followed by X-ray diffraction. Sample structures w...Co-doped ZnO nanoparticles are synthesized by co-precipitation method. The incorporation of Co ions into ZnO wur- zite structure with increasing Co concentrations was followed by X-ray diffraction. Sample structures were further studied by infrared spectra, from which a broad and strong absorption band in the range of 400 - 700 cm-1 and -OH stretching vibrational mode approximately 3400 cm-1 were observed. Ultraviolet-visible measurements showed a red shift of the absorption edge and four peaks at 468, 515, 577 and 629 nm in its reflectance spectra with increasing Co content. Magnetic measurements showed a ferromagnetic behavior for all samples. From the ESR spectra the presence of Co-metal clusters and Co-oxide precipitates are not observed and can be excluded as the origin of ferromagnetic in our samples. The ESR results are supported by UV-Vis measurements data.展开更多
在电化学氮还原(NRR)合成氨过程中,为了认识真实水环境对过渡金属掺杂氮碳材料催化NRR活性的影响,并筛选出实际催化性能最佳的构型,本研究通过密度泛函理论(DFT)和从头算分子动力学(AIMD)相结合的方法,对一系列不同配位形式的过渡金属...在电化学氮还原(NRR)合成氨过程中,为了认识真实水环境对过渡金属掺杂氮碳材料催化NRR活性的影响,并筛选出实际催化性能最佳的构型,本研究通过密度泛函理论(DFT)和从头算分子动力学(AIMD)相结合的方法,对一系列不同配位形式的过渡金属掺杂氮碳催化剂(TMN_(x)C_(y), TM=Sc、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn;x=1~4;y=4-x,总共40种构型)催化NRR的热力学稳定性和实际氮还原催化活性进行了系统研究.计算结果表明,本工作所研究的40种催化剂结构均具有较高的热力学稳定性,可作为实际的NRR候选催化剂.其中,利用隐性+显性水溶剂模拟真实水环境时,过渡金属V掺杂形成的VN3C1结构催化NRR酶机制过程的最大吉布斯自由能变值仅为0.35eV(在U=0 V vs. RHE时),表现出最佳的NRR催化性能.总体而言,本研究采用DFT与AIMD相结合的方法,深入地阐述了TMN_(x)C_(y)催化剂的实际NRR催化过程,为实验过程做出了更为贴切的理论预测.展开更多
The direct band gap ZnTe with transition metal （TM） impurities plays a vital role in optoelectronic and spintronic applications. In the present study, we use the advanced modified Becke-Johnson （mBJ） functional fo...The direct band gap ZnTe with transition metal （TM） impurities plays a vital role in optoelectronic and spintronic applications. In the present study, we use the advanced modified Becke-Johnson （mBJ） functional for performing the structural computations and detailed investigations of the optical characters in Zn1_xTMxTe （TM = Fe, Co） alloys with 0 ≤ x ≤1. By employing the FP-LAPW method, we determine various optical parameters for the ternary alloys and for the end binaries. The calculated static dielectric constants and optical band gaps for Zn1_xTMxTe （TM = Fe, Co） have an inverse relation that verifies the Penn model. We find that the static dielectric constant is nearly equal to the square of the static refractive index, and both increase with TM content. Furthermore, we also find a slight shift of peaks to a higher energy region with increasing TM concentration. The decreasing band gap and high value of the absorption in the visible region of electromagnetic spectrum make these alloys suitable for photonic and solar cell applications.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(grant nos.2018JBZ107 and 2019RC035)supported financially by the National Natural Science Foundation of China(grant nos.91961125 and 21905019)+1 种基金the Key Program for International S&T Cooperation Projects of China from the Ministry of Science and Technology of China(grant no.2018YFE0124600)the Chemistry and Chemical Engineering Guangdong Laboratory(nos.1932001,1932004,1911020,and 1911023).
文摘Precise catalysis is critical for the high-quality catalysis industry.However,it remains challenging to fundamentally understand precise catalysis at the atomic orbital level.Herein,we propose a new strategy to unravel the role of specific d orbitals in catalysis.The oxygen reduction reaction(ORR)catalyzed by atomically dispersed Pt/Co-doped Ti_(1−x)O_(2) nanosheets(Pt_(1)/Co_(1)-Ti_(1−x)O_(2))is used as a model catalysis.The z-axis d orbitals of Pt/Co-Ti realms dominate the O2 adsorption,thus triggering ORR.In light of orbital-resolved analysis,Pt_(1)/Co_(1)-Ti_(1−x)O_(2) is experimentally fabricated,and the excellent ORR catalytic performance is further demonstrated.Further analysis reveals that the superior ORR performance of Pt_(1)-Ti_(1−x)O_(2) to Co_(1)-Ti_(1−x)O_(2) is ascribed to stronger activation of Ti by Pt than Co via the d-d hybridization.Overall,this work provides a useful tool to understand the underlying catalytic mechanisms at the atomic orbital level and opens new opportunities for precise catalyst design.
文摘Co-doped ZnO nanoparticles are synthesized by co-precipitation method. The incorporation of Co ions into ZnO wur- zite structure with increasing Co concentrations was followed by X-ray diffraction. Sample structures were further studied by infrared spectra, from which a broad and strong absorption band in the range of 400 - 700 cm-1 and -OH stretching vibrational mode approximately 3400 cm-1 were observed. Ultraviolet-visible measurements showed a red shift of the absorption edge and four peaks at 468, 515, 577 and 629 nm in its reflectance spectra with increasing Co content. Magnetic measurements showed a ferromagnetic behavior for all samples. From the ESR spectra the presence of Co-metal clusters and Co-oxide precipitates are not observed and can be excluded as the origin of ferromagnetic in our samples. The ESR results are supported by UV-Vis measurements data.
文摘在电化学氮还原(NRR)合成氨过程中,为了认识真实水环境对过渡金属掺杂氮碳材料催化NRR活性的影响,并筛选出实际催化性能最佳的构型,本研究通过密度泛函理论(DFT)和从头算分子动力学(AIMD)相结合的方法,对一系列不同配位形式的过渡金属掺杂氮碳催化剂(TMN_(x)C_(y), TM=Sc、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn;x=1~4;y=4-x,总共40种构型)催化NRR的热力学稳定性和实际氮还原催化活性进行了系统研究.计算结果表明,本工作所研究的40种催化剂结构均具有较高的热力学稳定性,可作为实际的NRR候选催化剂.其中,利用隐性+显性水溶剂模拟真实水环境时,过渡金属V掺杂形成的VN3C1结构催化NRR酶机制过程的最大吉布斯自由能变值仅为0.35eV(在U=0 V vs. RHE时),表现出最佳的NRR催化性能.总体而言,本研究采用DFT与AIMD相结合的方法,深入地阐述了TMN_(x)C_(y)催化剂的实际NRR催化过程,为实验过程做出了更为贴切的理论预测.
基金supported by the Deanship of Scientific Research at King Saud University(for Shahid M Ramay)(Grant No.RG 1435-004)the University of the Punjab,Lahore for financial support through Faculty Research Grant Program(for M Hassan)the HEC Pakistan(Grant No.21-261/SRGP/R&D/HEC/2014)(for M Yaseen)
文摘The direct band gap ZnTe with transition metal （TM） impurities plays a vital role in optoelectronic and spintronic applications. In the present study, we use the advanced modified Becke-Johnson （mBJ） functional for performing the structural computations and detailed investigations of the optical characters in Zn1_xTMxTe （TM = Fe, Co） alloys with 0 ≤ x ≤1. By employing the FP-LAPW method, we determine various optical parameters for the ternary alloys and for the end binaries. The calculated static dielectric constants and optical band gaps for Zn1_xTMxTe （TM = Fe, Co） have an inverse relation that verifies the Penn model. We find that the static dielectric constant is nearly equal to the square of the static refractive index, and both increase with TM content. Furthermore, we also find a slight shift of peaks to a higher energy region with increasing TM concentration. The decreasing band gap and high value of the absorption in the visible region of electromagnetic spectrum make these alloys suitable for photonic and solar cell applications.
