Unlocking Dual-Pathway Low-Potential Aldehyde Oxidation on Chromium-Doped Copper Catalysts

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Low-potential aldehyde oxidation reaction (LPAOR) is crucial for hybrid water electrolysis and biomass fuel cells.
• Current research on Cu catalysts for LPAOR lacks full elucidation of reaction pathways and stability.
• Understanding reaction mechanisms is key to optimizing catalysts for energy-efficient hydrogen production and biomass upgrading.

Purpose of the Study:

• To prepare and investigate a Cr-doped mixed-valent Cu nanowire array catalyst (An-CrCu_xO-AC NWAs) for LPAOR.
• To elucidate the dual reaction pathways involved in LPAOR using the novel catalyst.
• To enhance LPAOR performance through Cr incorporation and electronic structure modulation.

Main Methods:

• Synthesis of Cr-doped mixed-valent Cu nanowire arrays (An-CrCu_xO-AC NWAs).
• Electrochemical characterization to evaluate LPAOR performance.
• Analysis of reaction pathways, including the role of OH* adsorption and C-H bond cleavage.
• Coupling LPAOR with oxygen reduction reaction (ORR) in a hybrid system.

Main Results:

• The An-CrCu_xO-AC NWAs catalyst facilitates parallel one-electron and two-electron pathways in LPAOR.
• Cr doping regulates OH* adsorption and H* generation, promoting water formation via the Volmer step.
• The Cr-doped catalyst achieves 100 mA cm^-2 at 0.224 V_RHE, outperforming undoped catalysts (0.271 V_RHE).
• A hybrid system utilizing An-CrCu_xO-AC NWAs reached a peak power density of 43.0 mW cm^-2.

Conclusions:

• Cr-doped Cu catalysts effectively elucidate dual pathways in LPAOR.
• Cr incorporation enhances catalyst performance by tuning electronic structure and adsorption properties.
• The developed catalyst shows significant potential for energy-efficient hydrogen production and biomass upgrading in hybrid electrochemical systems.