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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]

Hydrogen evolution reaction (HER) is regarded as a feasible strategy for producing high-purity hydrogen from abundant water. It is significant yet challenging for synthesis of Pt-based pH-universal HER electrocatalysts by substantially reducing the Pt loading without any decay in the activity. Herein, bimetallic PtRh alloyed dendritic nanoassemblies (DNAs) were efficiently prepared by a facile one-pot solvothermal strategy in oleylamine (OAm), coupling with the aid of glycine and cetyltrimethylammonium chloride (CTAC). By virtue of the unique branch-like structures and compositions advantages, the PtRh DNAs catalyst showed steeply enhanced HER activity with small overpotentials (i.e. 28 mV in 1.0 M KOH, 23 mV in 1.0 M phosphate buffer solution and 27 mV in 0.5 M H 2 SO 4) at the current density of 10 mA cm−2, surpassing those of commercial Pt/C under such conditions. This work provides a facile and rational strategy to construct advanced Pt-based bimetallic electrocatalyst for energy-correlated applications. Image 1 • PtRh DNAs were synthesized by a one-pot glycine- and CTAC-assisted solvothermal method. • The dendritic nanoassemblies with open structures had highly enlarged specific surface area. • The as-obtained catalyst showed dramatically boosted catalytic performances for HER in a wide pH range. [ABSTRACT FROM AUTHOR]

• The P-Co 2 MnO 4 /NF was synthesized by hydrothermal treatment, oxidation and P-doping. • The unique straw-like nanoneedle arrays provided large ECSA and rich active sites. • P-doping had the greatly improved HER activities. • The P-Co 2 MnO 4 /NF exhibited excellent HER activities in wide pH range of electrolytes. Developing high-performance and cut-price non-noble-metal electrocatalysts for hydrogen evolution reaction (HER) is desirable yet challenging. Herein, straw-like phosphorus-doped Co 2 MnO 4 nanoneedle arrays supported on nickel foam (P-Co 2 MnO 4 /NF) were prepared by successive hydrothermal treatment, oxidation and P doping for high-efficiency HER. Benefiting from the unique needle-like arrays and compositions advantages, P-Co 2 MnO 4 /NF exhibited excellent HER activities with the overpotentials of 33, 43 and 102 mV to afford a current density of 10 mA cm−2 in alkaline, acidic and neutral media, respectively, coupled with the long-term electrochemical stability. This work affords an effective avenue for preparation of cost-effectiveness, high-efficiency and wide-pH HER catalysts for electrochemical energy technologies. [ABSTRACT FROM AUTHOR]