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Your search keyword '"Wang, Jiajun"' showing total 102 results
Start Over Author "Wang, Jiajun" Publisher american chemical society
102 results on '"Wang, Jiajun"'

1. Exploiting Topological Darkness in Photonic Crystal Slabs for Spatiotemporal Vortex Generation

Author

Liu, Wenzhe, Wang, Jiajun, Tang, Yang, Wang, Xinhao, Zhao, Xingqi, Shi, Lei, Zi, Jian, Chan, Che Ting, Liu, Wenzhe, Wang, Jiajun, Tang, Yang, Wang, Xinhao, Zhao, Xingqi, Shi, Lei, Zi, Jian, and Chan, Che Ting

Abstract

Spatiotemporal optical vortices (STOVs) with swirling phase singularities in space and time hold great promise for a wide range of applications across diverse fields. However, current approaches to generate STOVs lack integrability and rely on bulky free-space optical components. Here, we demonstrate routine STOV generation by harnessing the topological darkness phenomenon of a photonic crystal slab. Complete polarization conversion enforced by symmetry enables topological darkness to arise from photonic bands of guided resonances, imprinting vortex singularities onto an ultrashort reflected pulse. Utilizing time-resolved spatial mapping, we provide the first observation of STOV generation using a photonic crystal slab, revealing the imprinted STOV structure manifested as a curved vortex line in the pulse profile in space and time. Our work establishes photonic crystal slabs as a versatile and accessible platform for engineering STOVs and harnessing the topological darkness in nanophotonics. © 2024 The Authors. Published by American Chemical Society.

Published
2024

2. Morphology and Structural Regulation of S and Cr Co-doped FeOOH Nanoarray for Promoting Oxygen Evolution Reaction.

Author

Mu, Jianshuai, Peng, Aizhu, Wang, Xinran, Wang, Jin, Hong, Zengjiao, Guo, Danna, Lei, Shulai, Wang, Jiajun, and Yang, En-Cui

Abstract

Designing low-cost and environmentally friendly oxygen evolution reaction (OER) electrocatalysts to enhance the electrocatalytic water decomposition to produce hydrogen still faces great challenges. In this work, a feasible strategy for metallic/nonmetallic elements co-doping to boost the OER catalytic properties of iron oxyhydroxide is proposed. A series of S and Cr co-doped iron oxyhydroxides nanoarrays loaded on nickel foam (Sx,Cr-FeOOH/NF) were prepared by an electrodeposition–hydrothermal method. The optimized S0.1,Cr-FeOOH/NF exhibits a superior electrocatalytic OER performance with low overpotential (235 mV at 100 mA cm–2), highly outperforming commercial RuO2. Meanwhile, the overpotential of S0.1,Cr-FeOOH/NF increases by only 4 mV after 70 h of stability testing at 100 mA cm–2, demonstrating its durability. The nanoarray with ultrathin nanosheets of S0.1,Cr-FeOOH/NF regulated by S and Cr co-doping can offer abundant active sites and also facilitate mass transportation. The density functional theory (DFT) calculation results show that S and Cr co-doping modifies the electronic structure of S0.1,Cr-FeOOH/NF, which thus optimizes the adsorption energy toward the OER intermediates, promotes the transformation of *O to *OOH (rate-determining step), and thus accelerates the OER kinetics. [ABSTRACT FROM AUTHOR]

Published
2024
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34. Hollow Co9S8/CdS Nanocages as Efficient Photocatalysts for Hydrogen Evolution.

Author

Xia, Chang, Xue, Chongyu, Bian, Weixiao, Liu, Jia, Wang, Jiajun, Wei, Yajuan, and Zhang, Jingbo

Abstract

The development of highly efficient photocatalysts is the key for the application of hydrogen production. Due to the narrow band gap and high catalytic activity, Co9S8 is considered as a prospective photocatalyst for hydrogen evolution from water splitting. Nevertheless, the serious recombination of carriers on Co9S8 always results in an ultrapoor performance on hydrogen evolution. Herein, we combine CdS quantum dots on hollow dodecahedron Co9S8 to form heterostructured Co9S8/CdS nanocages by a low-energy atmospheric one-pot strategy. Owing to the Z-type heterojunction, the hollow structure, size effect of quantum dots, and abundant active sites, the separation and migration of carriers are accelerated, and the electron–hole recombination is successfully suppressed. The catalyst hollow Co9S8/CdS nanocages show a remarkable activity with the hydrogen production efficiency of 14963 μmol·h–1·g–1, which is 5.7 and 28.5 times as high as those of pure CdS and Co9S8, respectively. Besides, the long-term (up to 30 h) stability also indicates that the photocatalyst hollow Co9S8/CdS nanocages have a great potential in the photocatalytic splitting of water for hydrogen evolution. [ABSTRACT FROM AUTHOR]

Published
2021
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