Accelerating gas escape efficiency by parallel alignment of nanosheets arrays for high-current oxygen evolution and urea oxidation.

Electrocatalysts play a crucial role in energy production and chemical oxidation. Nonetheless, the efficacy of catalysts in expediting reactions is notably affected by the escape of bubbles and the re-exposure of active sites, particularly under high-current-density conditions. Herein, parallel-aligned Ni(OH) 2 nanosheets array is anchored on nickel foam as substrate to verify mass transfer enhancement theory. Compare with disordered and interconnected nanosheets structures, parallel alignment of nanosheets array with superior mass transfer capability, larger exposed surface area, and spatial confinement effects is demonstrated to boost effective removal of in situ generated gas bubbles. Moreover, carbon coating layer with high electrical conductivity and nickel-iron-based composite with high activity is simultaneously anchored on parallel-aligned nanosheets surface (C@FeNi/NF-P). As illustration of application viability, C@FeNi/NF-P exhibits overpotential of 317 mV and potential of 1.45 V at 500 mA cm−2, respectively, for oxygen evolution (OER) and urea oxidation (UOR) with good stability. Moreover, the mass transfer enhancement effect of parallel aligned structure for the high active electrodes is also discussed. This work provides new insight for physical structural modulation of active materials to strengthen electrocatalytic activity with high mass-transfer efficiency, further ensuring high-efficient and stable water splitting and urea oxidation. [Display omitted] • The parallel-aligned nanosheets arrays is fabricated by lattice matching growth. • Open and confined structure can promote bubbles release and active sites exposure. • Carbon layer and Fe-dopant are introduced to enhance conductivity and activity. • Superior OER and UOR activity can be achieved at 500 mA cm−2 with high stability. • Structure alignment of active materials plays universal role in activity modulation. [ABSTRACT FROM AUTHOR]