Engineering topics

Jiang, Shaojie

Publications and source records attributed to Jiang, Shaojie.

3 records

DOE OSTI2024

Randomly Layered Superstructure of In 2 O 3 Truncated Nano-Octahedra and Its High-Pressure Behavior

This study outlines the synthesis and characterization of a unique superlattice composed of vertex-truncated indium oxide (In 2 O 3 ) nano-octahedra, along with an exploration of its response to high-pressure conditions. Here, using a bright-field transmission electron microscope (BF-TEM), we determined an average circumradius of 15.2 nm for these octahedral building blocks. The resilience and response of the superlattice to pressure variations, peaking at 18.01 GPa, were examined by employing synchrotron-based Wide-Angle X-ray Scattering (WAXS) and Small-Angle X-ray Scattering (SAXS) techniques. The WAXS data revealed no phase transitions, reinforcing the stability of the 2D superlattice comprised of random layers in alignment with a 2D p31m symmetry. Notably, the SAXS data unveiled a pressure-induced, irreversible octahedron translation and ligand interaction occurring within the random layer. Through our examination of these pressure-sensitive behaviors, we identified a distinctive translation model inherent to octahedra and observed modulation in the superlattice cell parameter induced by pressure. This research signifies a noteworthy progression in deciphering the intricate behaviors of 2D superlattices under high-pressure conditions.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Enhanced Oxygen Reduction Performance on {101} CoMn 2 O 4 Spinel Facets

Here, we present a facile colloidal synthesis method for producing {101}-facet-tailored CoMn 2 O 4 spinel nano-octahedra with uniform size (9 nm). These nano-octahedra exhibit superior electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media compared to their spherical counterparts and previously reported spinel electrocatalysts. At 0.85 V, they achieve a high mass activity (MA) of 60.0 A/g, surpassing the spherical counterparts (38.6 A/g). Furthermore, the CoMn 2 O 4 nano-octahedra demonstrate excellent stability, maintaining an MA of 47.2 A/g after 10,000 durability cycles. This work highlights a promising approach for synthesizing advanced spinel nano-oxides with controlled crystal facets, offering potential as non-precious metal ORR electrocatalysts. The exposed active catalyst surfaces and well-defined structures contribute to their enhanced ORR performance.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Improving Oxygen Reduction Performance of Surface-Layer-Controlled Pt–Ni Nano-Octahedra via Gaseous Etching

This study demonstrates an atomic composition manipulation on Pt–Ni nano-octahedra to enhance their electrocatalytic performance. By selectively extracting Ni atoms from the {111} facets of the Pt–Ni nano-octahedra using gaseous carbon monoxide at an elevated temperature, a Pt-rich shell is formed, resulting in an ~2 atomic layer Pt-skin. The surface-engineered octahedral nanocatalyst exhibits a significant enhancement in both mass activity (~1.8-fold) and specific activity (~2.2-fold) toward the oxygen reduction reaction compared with its unmodified counterpart. After 20,000 potential cycles of durability tests, the surface-etched Pt–Ni nano-octahedral sample shows a mass activity of 1.50 A/mg Pt , exceeding the initial mass activity of the unetched counterpart (1.40 A/mg Pt ) and outperforming the benchmark Pt/C (0.18 A/mg Pt ) by a factor of 8. DFT calculations predict this improvement with the Pt surface layers and support these experimental observations. Therefore, this surface-engineering protocol provides a promising strategy for developing novel electrocatalysts with improved catalytic features.

36 MATERIALS SCIENCE↗