Palladium-Functionalized Nanostructured Nickel-Cobalt Oxide as Alternative Catalyst for Hydrogen Sensing Using...

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Development of advanced catalysts is crucial for sensitive hydrogen detection.
• Noble metal catalysts are effective but costly, necessitating alternatives.
• Nanostructured metal oxides offer tunable properties for catalytic applications.

Purpose of the Study:

• To synthesize and evaluate a palladium-functionalized nanostructured Ni0.5Co2.5O4 catalyst for hydrogen sensing.
• To investigate the effect of palladium loading and synthesis method on catalyst performance.
• To assess the catalyst's sensitivity, stability, and cross-sensitivity to humidity.

Main Methods:

• Coprecipitation synthesis of palladium-functionalized Ni0.5Co2.5O4.
• Characterization using scanning transmission electron microscopy (STEM) and energy-dispersive X-ray (EDX).
• Testing in planar pellistor sensors at 400 °C in dry and humid air.

Main Results:

• Synthesized catalyst exhibited a sheet-like morphology with high palladium distribution.
• Achieved a sensor response of 109 mV/10,000 ppm H2 (25% of LFL), a 4.6-fold increase over pristine Ni0.5Co2.5O4.
• Demonstrated reduced humidity cross-sensitivity (~10%) compared to pristine Ni0.5Co2.5O4 (~27%).

Conclusions:

• Palladium-functionalized Ni0.5Co2.5O4 shows high sensitivity and stability for hydrogen detection below LFL.
• The catalyst's performance is attributed to strong metal-metal oxide interactions and high Pd dispersion.
• Promising for developing next-generation hydrogen sensors with improved safety and reliability.