2 research outputs found
Size-Controlled Synthesis and Microstructure Investigation of Co<sub>3</sub>O<sub>4</sub> Nanoparticles for Low-Temperature CO Oxidation
Noble-metal-free functional oxides are active catalysts
for CO oxidation at low temperatures. Spinel-type cobalt oxide (Co<sub>3</sub>O<sub>4</sub>) nanoparticles can be easily synthesized by
impregnation of activated carbon with concentrated cobalt nitrate
and successive carbon burn off. Mean size and particle size distribution
can be tuned by adding small amounts of silica to the carbon precursor,
as witnessed by whole powder pattern modeling of the X-ray powder
diffraction data. The catalytic tests performed after silica removal
show a significant influence of the mean domain size and of size distribution
on the CO oxidation activity of the individual Co<sub>3</sub>O<sub>4</sub> specimens, whereas defects play a less important role in
the present case
Design of N‑Coordinated Dual-Metal Sites: A Stable and Active Pt-Free Catalyst for Acidic Oxygen Reduction Reaction
We develop a host-guest strategy
to construct an electrocatalyst
with Fe-Co dual sites embedded on N-doped porous carbon and demonstrate
its activity for oxygen reduction reaction in acidic electrolyte.
Our catalyst exhibits superior oxygen reduction reaction performance,
with comparable onset potential (<i>E</i><sub>onset</sub>, 1.06 vs 1.03 V) and half-wave potential (<i>E</i><sub>1/2</sub>, 0.863 vs 0.858 V) than commercial Pt/C. The fuel cell
test reveals (Fe,Co)/N-C outperforms most reported Pt-free catalysts
in H<sub>2</sub>/O<sub>2</sub> and H<sub>2</sub>/air. In addition,
this cathode catalyst with dual metal sites is stable in a long-term
operation with 50 000 cycles for electrode measurement and
100 h for H<sub>2</sub>/air single cell operation. Density functional
theory calculations reveal the dual sites is favored for activation
of O-O, crucial for four-electron oxygen reduction