3D Hierarchical NiCo Layered Double Hydroxide Nanosheet Arrays Decorated with Noble Metal Nanoparticles for Enhanced Urea Electrocatalysis

• Published in: ChemElectroChem Vol. 7; no. 1; pp. 163 - 174
• Main Authors: Khalafallah, Diab, Xiaoyu, Li, Zhi, Mingjia, Hong, Zhanglian
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 02.01.2020
• Subjects: Arrays; Clean energy; double layered hydroxide; Electrocatalysis; Electrocatalysts; Electronic structure; Energy conversion; Fuel cells; Hydroxides; Interlayers; Intermetallic compounds; Nanoparticles; nanosheet arrays; Nanosheets; Noble metals; Oxidation; Palladium; Platinum; Reaction kinetics; Silver; Sustainable development; Urea; urea electrocatalysis
• ISSN: 2196-0216; 2196-0216
• DOI: 10.1002/celc.201901423

The electrocatalysis of urea represents an important potential as an efficient technology for sustainable energy development. This anodic reaction generates hydrogen or electrical power through direct electrooxidation of urea molecules, but is greatly inhibited by its slow kinetics. Therefore, tailoring highly efficient, earth‐abundant, and durable electrocatalysts for urea oxidation reaction (UOR) is a fundamental for the enhancement of green energy conversion technologies. Herein, we report a scalable synthetic strategy to construct three‐dimensional (3D) nickel‐cobalt layered double hydroxide nanosheet arrays (NiCo−LDH NSAs) with silver (Ag0) or gold (Au0) and palladium (Pd0) intercalants as high performance catalysts for UOR. Experimental results suggest that the interlayer spacing of multi‐anions LDH NSAs can effectively afford synergetic effects of increased electrochemical surface area, better exposure of catalytically active sites, and favorable adsorption energy of urea molecules. As expected, the deposition of noble metal nanoparticles (NPs) could successfully modulate the electronic structure, delivering a rise to significantly improved UOR activity. Specifically, the Au/NiCo−LDH hybrid exhibits a superior electro‐catalytic performance toward urea electrooxidation with a highest current. These findings offer an effective pathway to prepare potential earth‐abundant electrocatalysts for direct urea fuel cells (DUFCs). Golden catalyst: 3D highly porous Au/NiCo−LDH architecture was fabricated and applied as an electrocatalyst for urea catalysis in alkaline environment with a high‐performance benefiting from the vertical orientation of nanosheets building blocks with multiple void spaces/passages, facile diffusion of ions and mass at both interiors and outer surfaces, and enriched active sites as well. The robustly deposited Au nanoparticles could significantly improve the electronic structure and thus boosted the catalytic activity of the hybrid.