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[Display omitted] • The ultrathin RhIr NSs/NF was prepared by a simple and mild one-pot aqueous strategy at room temperature. • The unique sheet-like architectures provided large ECSA and exposed high-density active sites. • The self-supported RhIr NSs/NF had excellent HER activity and stability for the HER over a wide pH range. The development of low-cost and high-efficiency electrocatalysts is very important for electrocatalytic hydrogen evolution reaction (HER) in water splitting system. Herein, ultrathin rhodium-iridium nanosheets were facilely in-situ grown on nickel foam (RhIr NSs/NF) by a one-pot aqueous strategy at room temperature. The sheet-like structures with the film thickness of 78 nm were identified by scanning electron microscopy and transmission electron microscopy. The catalyst showed greatly high HER features in both 1.0 M KOH and 0.5 M H 2 SO 4 with the overpotentials of 15 and 14 mV to achieve 10 mA cm−2, respectively, surpassing most Pt-free catalysts. Also, the RhIr NSs/NF exhibited amazing catalytic stability during the long-term operation. This study offers a facile and rational pathway for design and synthesis of advanced HER electrocatalysts for energy conversion devices. [ABSTRACT FROM AUTHOR]

Developing earth-rich and high-efficiency nonprecious metal catalysts is critical but extremely challenging for oxygen evolution reaction (OER). Herein, a simple room-temperature sulfuration method was developed for in situ synthesis of walnut kernel-like iron-cobalt-nickel sulfide nanosheets on nickel foam (FeCoNiS x /NF). The unique nanosheets exposed abundant active sites and provided large electrochemically active surface area. The as-built FeCoNiS x /NF exhibited high OER performances with the small overpotentials of 231 and 268 mV to afford 10 and 50 mA cm−2 in 1.0 M KOH, respectively, coupled with a small Tafel slope of 55 mV dec−1. Furthermore, the FeCoNiS x /NF acted as the anode towards overall water electrolysis with acceptable results, where commercial Pt/C dropped on the NF worked as the cathode. This study provides some valuable insights for rational construction of nonprecious electrocatalysts in electrochemical energy technologies. [ABSTRACT FROM AUTHOR]

Developing cost-effectiveness and superior electrocatalysts is crucial to improve the efficiency of oxygen evolution reaction (OER) in water splitting system. Hence, flower-like phosphorus doped Ni 3 S 2 /CoFe 2 O 4 arrays (P-Ni 3 S 2 /CoFe 2 O 4 /NF) were generated on three-dimensional (3D) nickel foam (NF) via the two-step hydrothermal treatment and subsequent phosphorization. Additionally, a series of control experiments were conducted to investigate the formation mechanism. By virtue of the unique 3D configurations and multi-compositions, the as-prepared catalyst exhibited greatly improved OER performance in 1.0 M KOH solution, with the overpotential of only 254 mV at 50 mA cm−2 and low Tafel slope of 54.43 mV dec−1. This study provides a feasible approach for preparing advanced electrocatalyst in energy conversion and storage devices. [ABSTRACT FROM AUTHOR]

Exploring advanced nanocatalysts are of importance for hydrogen evolution reaction (HER) in alkaline electrolyte (e.g. 1.0 M KOH). Herein, porous iridium-palladium-plumbum wire-like nanonetworks (IrPdPb WNNs) were prepared by a facile one-pot aqueous method with octylphenoxypolyethoxyethanol (NP-40) as the structure-director. The resultant IrPdPb WNNs exhibited superior HER performance in the alkaline electrolyte, such as ultra-low overpotential (21 mV) to drive a current density of 10 mA cm−2, small Tafel slope (66 mV dec−1), and high exchange current density (4.87 mA cm−2), surpassing commercial Pt/C. This study provides a simple strategy for synthesis of advanced multi-metallic electrocatalysts in energy storage and conversion. [ABSTRACT FROM AUTHOR]

Exploring high-performance and stable transition metal electrocatalysts is prerequisite for boosting overall water splitting efficiency. In this study, iron (Fe), manganese (Mn) co-doped three-dimensional (3D) Ni 3 S 2 nanoflowers were in situ assembled by many inter-connected 2D nanosheets on nickel foam (NF) via hydrothermal and sulfuration treatment. By virtue of the introduced Fe and Mn elements and unique flower-like structures, the as-prepared catalyst displayed high activity and stability for oxygen evolution reaction (OER), coupled with a small Tafel slope (63.29 mV dec−1) and a low overpotential of 216 mV to reach the current density of 30 mA cm−2. This study would shed some lights for facile synthesis of exceptional OER catalyst by tailoring the electronic structure and doping transition metal(s). [ABSTRACT FROM AUTHOR]