Pt nanoparticles/Fe-doped α-Ni(OH)2 nanosheets array with low Pt loading as a high-performance electrocatalyst for alkaline hydrogen evolution reaction.

To decrease energy loss in water-alkali electrolysis, it is crucial to construct highly active HER electrocatalyst in alkaline media. In this work, Pt nanoparticles uniformly immobilized on Fe-doped α-Ni(OH) 2 nanosheets array with low Pt loading was designed through one-step liquid-phase route. Impressively, the optimized Pt 2.3% -Fe 0.05 Ni 0.95 (OH) 2 with ∼3.5 nm size of Pt nanoparticles displays superior HER electrocatalytic performance in alkaline electrolyte. It can drive 10 mA cm−2 at very low overpotential of 18 mV, and 500 mA cm−2 of high current density at fairly low overpotential of 159 mV with a small Tafel slope of 25.6 mV dec−1. Its mass activity is 15.23 mA μg Pt −1 at − 0.070 V vs. RHE, almost 28.7 times relative to Pt/C. Moreover, it presents distinguished stability in both low and high current densities. Fe3+ ions doped in α-Ni(OH) 2 lattice by partial substitution of Ni2+ ions provides a good platform for anchoring ultrafine Pt nanoparticles. A synergy between the Fe-doped α-Ni(OH) 2 nanosheets interface for water dissociation and the Pt nanoparticles surface for adsorbed H atoms recombination enhances the catalytic activity for HER. The strong contact between Pt nanoparticles and site-specific Fe3+-O(H)–Pt bonds of Fe-doped α-Ni(OH) 2 nanosheets is contributed to its outstanding activity and stability. Image 1 • Pt nanoparticles/Fe-doped α-Ni(OH) 2 nanosheets array is constructed. • The Pt loading is as low as 2.3%. • It can serve as a high-performance electrocatalyst for alkaline HER. • It can deliver 10 mA cm−2 at a low overpotential of 18 mV. • It can drive 500 mA cm−2 at a low overpotential of 159 mV. [ABSTRACT FROM AUTHOR]