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Zhao, Jiajun

Publications and source records attributed to Zhao, Jiajun.

4 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Manipulating the oxygen reduction reaction pathway on Pt-coordinated motifs

Electrochemical oxygen reduction could proceed via either 4e - -pathway toward maximum chemical-to-electric energy conversion or 2e - -pathway toward onsite H 2 O 2 production. Bulk Pt catalysts are known as the best monometallic materials catalyzing O 2 -to-H 2 O conversion, however, controversies on the reduction product selectivity are noted for atomic dispersed Pt catalysts. Here, we prepare a series of carbon supported Pt single atom catalyst with varied neighboring dopants and Pt site densities to investigate the local coordination environment effect on branching oxygen reduction pathway. Manipulation of 2e - or 4e - reduction pathways is demonstrated through modification of the Pt coordination environment from Pt-C to Pt-N-C and Pt-S-C, giving rise to a controlled H 2 O 2 selectivity from 23.3% to 81.4% and a turnover frequency ratio of H 2 O 2 /H 2 O from 0.30 to 2.67 at 0.4 V versus reversible hydrogen electrode. Energetic analysis suggests both 2e - and 4e - pathways share a common intermediate of *OOH, Pt-C motif favors its dissociative reduction while Pt-S and Pt-N motifs prefer its direct protonation into H 2 O 2 . By taking the Pt-N-C catalyst as a stereotype, we further demonstrate that the maximum H 2 O 2 selectivity can be manipulated from 70 to 20% with increasing Pt site density, providing hints for regulating the stepwise oxygen reduction in different application scenarios.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Downregulation of miR-892b inhibits the progression of osteoarthritis via targeting cyclin D1 and cyclin D2

Highlights: • miR-892b antagomir reversed IL-1β-induced chondrocyte growth inhibition. • miR-892b directly targeted cyclin D1 and cyclin D2. • miR-892b antagomir inhibited the symptom of osteoarthritis in vivo. Osteoarthritis (OA) is an orthopedic inflammatory disease which can cause functional disability and chronic pain. MiRNAs are known to play important roles in OA. To identify the targets for the treatment of OA, bioinformatics analysis was performed to explore differentially expressed miRNAs between OA and normal samples.

60 APPLIED LIFE SCIENCES↗