Thermal responsive Rh₁-Pd single-atom catalyst for controlling activity in direct formic acid fuel cells

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Single-atom catalysts offer high activity but lack
• smart
• properties like thermal responsiveness.
• Achieving controllable catalytic activity in single-atom catalysts remains a challenge.

Purpose of the Study:

• To design thermosensitive single-atom Rh-Pd nanosheets (NSs) with temperature-controlled electro-catalytic activity.
• To utilize amino functionalized poly(N-isopropylacrylamide) as a thermal responsive gate for catalyst activity control.
• To investigate the application of these smart catalysts in direct formic acid fuel cells (DFAFCs).

Main Methods:

• Synthesis of thermosensitive single-atom Rh-Pd nanosheets.
• Electrocatalytic testing using formic acid electro-oxidation as a model reaction.
• In-situ spectroscopy and theoretical calculations to understand catalytic mechanisms.
• Performance evaluation in direct formic acid fuel cells (DFAFCs).

Main Results:

• The thermosensitive Rh₁-Pd NSs demonstrated high mass activity (2.29 A mg_PGM^-1) and strong poisoning resistance.
• Reversible thermo-responsibility was observed at a lower critical solution temperature (LCST) of 35 °C.
• The catalyst favored the direct formate pathway, weakening the binding of self-poisonous species.
• DFAFCs with these NSs showed high power density below the LCST and sharp power drop above it, enabling intelligent thermal protection.

Conclusions:

• Thermosensitive single-atom Rh-Pd NSs can be designed with controllable electro-catalytic activity via a thermal responsive gate.
• These smart catalysts exhibit excellent performance and anti-self-poisoning properties for formic acid electro-oxidation.
• The developed material offers intelligent thermal protection for direct formic acid fuel cells (DFAFCs).