High-performance and cost-effective electrocatalysts are essential for both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Herein, we provide the first report about a facile colloidal method to fabricate 2D ultrathin ternary FeNiS 2 nanosheets (NSs). When serving as an OER catalyst under alkaline conditions, they exhibited superior electrocatalytic performance over RuO 2 and achieved a current density of 10 mA cm −2 with a potential of 1.54 V and a Tafel slope of 46 mV decade − 1 . Meanwhile, an ORR catalytic activity was also achieved with an onset potential of 0.78 V, a Tafel slope of 107 mV decade − 1 , and a high selectivity with electron transfer number of 3.92 and H 2 O 2 % of 3.6% at 0.3 V under neutral conditions, which were comparable to those of the commercial Pt/C. The ternary FeNiS 2 -NSs were superior over the binary FeS NSs and Ni 9 S 8 nanorods synthesized via the same routes. More importantly, with the resistance for the corrosion and poison from the alkaline and phosphate buffer solution , the FeNiS 2 NSs exhibited superior stability without apparent OER or ORR catalytic activity loss over long-term operation. Their enhanced electrocatalytic performance compared to their binary counterparts indicate that a new strategy to prepare high performance OER and ORR catalysts was developed. In addition, the as-prepared FeNiS 2 NSs could serve as a noble-metal-free catalyst for OER or ORR with good electrocatalytic activities and long-term stability for practical applications.
It is critical to developing electrocatalysts with highly active and cost-effective for oxygen evolution to resolve environmental pollution and energy issues, in which FeNi-based nanomaterials hold a great promise. Herein, (Fe 0.33 Ni 0.67 )S 2 and (Fe 0.33 Ni 0.67 )S 2 /reduced graphene oxide (rGO)- x % ( x = 10, 20) composites, which exhibited highly efficient oxygen evolution reaction (OER) electrocatalytic activity under alkaline conditions, were synthesized via a hydrothermal approach and following thermal treatment with sulfur powders. Benefiting from the integrated structure of (Fe 0.33 Ni 0.67 )S 2 and support of conductive graphene backbones, (Fe 0.33 Ni 0.67 )S 2 /rGO-20% electrocatalyst showed the best OER activity with an overpotential of 172 mV at 10 mA·cm −2 and Tafel slopes of 45 mV·decade −1 . The composition, phase, and surface structure of the catalyst were characterized before and after OER reaction. The results indicated that crystal phase of the catalyst was reconstructed to the amorphous crystalline features after OER, with oxidation of iron-nickel sulfide and appearance of Ni–Fe oxo/hydroxide species, which may play a crucial role in the high OER performance as the catalytic-active. Moreover, in a two-electrode system towards overall water splitting with (Fe 0.33 Ni 0.67 )S 2 /rGO-20%/NF and Pt/C/NF as the anode and cathode, respectively, the catalysts exhibited excellent catalytic performance with the voltage of only 1.42 V at 10 mA·cm −2 . Graphical abstract
危险品化学品经营许可证（带存储）