Engineering topics

Zheng, Hongkui

Publications and source records attributed to Zheng, Hongkui.

3 records

DOE OSTI2024

Engineering of a Coupled Nanocomposite as a High-Performance Protonic Ceramic Fuel Cell Cathode

The lack of high-performance cathode catalysts is a salient issue that bedeviled the commercialization of protonic ceramic fuel cells (PCFCs). Here, in this work, we report a remarkable electrocatalytic activity and stability enhancement of cathode electrodes by engineering a coupled nanocomposite. The as-prepared Pr 0.3 (Ba 0.5 Sr 0.5 ) 0.7 Co 0.8 Fe 0.2 O 3−δ nanocomposite possesses a bulk cubic phase on which homogeneous and intimate orthorhombic PrCo 0.5 Fe 0.5 O 3−δ nanoparticles are uniformly decorated. X-ray diffraction and Raman spectroscopy reveal the excellent thermal stability of the nanocomposite. It achieves a high peak power density of 1.02 W cm –2 based on protonic electrolytes at 600 °C. No noticeable structural degradation is observed over ∼210 h at 550 °C according to scanning electron microscopy analysis. This work demonstrates an effective strategy to boost the performance of perovskite oxides for PCFCs via nanocomposite engineering. It may apply to other catalyst designs and discoveries, such as for batteries, electrolyzers, and membrane reactors.

08 - HYDROGEN↗

DOE OSTI2023

Enhanced electrolysis performance through hierarchical nanoparticle formation in the BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ cathode materials system

This study demonstrated that the activity of a triple conducting BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ (BCFZY0.1) air cathode was improved by in situ formation BCFZY0.1 nanoparticles (NPs). The NPs, directly formed from the reaction of BCFZY0.1 with H 2 O and CO 2 from air under electrolysis measurements conditions, were uniformly distributed in a porous BCFZY0.1 framework. At 600 °C, the current density increased and reached a plateau of 1.12 A/cm 2 with the hierarchical BCFZY0.1 cathode under electrolysis conditions within 400 h operation. Distribution of Relaxation Time (DRT) measurements found that the polarization resistance decreased over time as NPs were formed. Furthermore, SEM and TEM results confirm the nanoparticle formation, and the chemical and structural features were assigned to a BCFZY0.1 phase.

08 HYDROGEN↗

DOE OSTI2022

van der Waals Semiconductor Empowered Vertical Color Sensor

We report biomimetic artificial vision is receiving significant attention nowadays, particularly for the development of neuromorphic electronic devices, artificial intelligence, and microrobotics. Nevertheless, color recognition, the most critical vision function, is missed in the current research due to the difficulty of downscaling of the prevailing color sensing devices. Conventional color sensors typically adopt a lateral color sensing channel layout and consume a large amount of physical space, whereas compact designs suffer from an unsatisfactory color detection accuracy. In this work, we report a van der Waals semiconductor-empowered vertical color sensing structure with the emphasis on compact device profile and precise color recognition capability. More attractive, we endow color sensor hardware with the function of chromatic aberration correction, which can simplify the design of an optical lens system and, in turn, further downscales the artificial vision systems. Also, the dimension of a multiple pixel prototype device in our study confirms the scalability and practical potentials of our developed device architecture toward the above applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗