Developing efficient and stable electrocatalysts has always been the focus of electrochemical research. Here, sea urchin-like nickel-molybdenum bimetallic phosphide nickel-molybdenum alloy (Ni4Mo) and (Ni-Mo-P) were successfully synthesized by hydrothermal, annealing and phosphating methods on nickel foam (NF). The unusual shape of the sea urchin facilitates gas release and mass transfer and increases the interaction between catalysts and electrolytes. The Ni4Mo/NF and Ni-Mo-P/NF electrodes only need overpotentials of 72 and 197 mV to reach 50 mA·cm−2 under alkaline conditions for hydrogen evolution reaction and oxygen evolution reaction, respectively. The Ni4Mo/NF and Ni-Mo-P/NF asymmetric electrodes were used as anode and cathode for the overall water splitting, respectively. In 1.0 M KOH, at a voltage of 1.485 V, the electrolytic device generated 50 mA·cm−2 current density, maintaining for 24 h without reduction. The labor presents a simple method to synthesize a highly active, low-cost, and strongly durable self-supporting electrode for over-water splitting.

Developing highly efficient and stable electrocatalysts is the key to realize hydrogen production from industrial electrolytic water. In this study, we constructed Co(OH)(2) and CoP ultrathin nanosheet arrays on titanium mesh using electrodeposition and phosphating processes. In alkaline conditions, the Co(OH)(2)/Ti-2.0 needed overpotentials of 414 and 457 mV to achieve 500 and 1000 mA cm(-2) for oxygen evolution reaction. Mechanism research showed that CoOOH formed by pre-oxidation of Co(OH)(2) was the actual active substance. After low-temperature phosphorization of Co(OH)(2), CoP nanosheets generated abundant defects and increased reactive sites, and CoP/Ti-2.0 exhibited high activity in the all-pH hydrogen evolution reaction (overpotentials of 106, 116, and 131 mV in acidic, alkaline, and neutral solutions at 10 mA cm(-2), respectively). Density functional theory calculations showed the free energy of hydrogen adsorption of CoP. As efficient electrode materials, the Co(OH)(2) and CoP ultrathin nanosheet arrays on Ti mesh can be assembled to an alkaline electrolyzer, which required only 1.530 V to drive 50 mA cm(-2) for overall water splitting with strong durability.

Fabrication of composite materials on 3D copper foam for electrochemical research.

The rational design of hierarchical hollow nanomaterials is of critical significance in energy storage materials. Herein, dual-wall hollow nanospheres (DWHNS) Sn/MoS2@C are constructed by in situ confined growth and interface engineering. The inner hollow spheres of Sn/MoS2 are formed by atomic soldering MoS2 nanosheets with liquid Sn at high temperature. The formation mechanism of the hierarchical structure is explored by the morphology evolutions at different temperatures. The DWHNS Sn/MoS2@C manifest abundant inner space and high specific surface area, which provides more support sites for Li+/Na+/K+ storage and alleviates the volume effect of tin-based electrode materials to a certain extent. The composite material manifests an outstanding specific capacity and satisfactory reversibility of lithium ion batteries (∼931 mAh g-1 at 1 A g-1 after 500 cycles), sodium ion batteries (∼432 mAh g-1 at 1 A g-1 after 400 cycles), and potassium ion batteries (∼226 mAh g-1 at 1 A g-1 after 300 cycles). Additionally, the morphology evolution and mechanism analysis of DWHNS Sn/MoS2@C in alkali metal ion batteries are verified by ex situ measurement, which confirms the three-in-one hybrid storage mechanism, i.e., intercalation reaction of carbon shells, conversion reaction of MoS2, and alloying reaction of tin.

Reduced graphene oxide/Ag nanoparticles hybrids (rGO/AgNPs) were fabricated via a green and facile hydrothermal method. The as-synthesized materials were characterized in detail using various spectroscopic and microscopic techniques. Under a suitable dosage of silver ions, well-dispersed AgNPs on the reduced graphene oxide sheets were obtained. The surface plasmon resonance properties of AgNPs on graphene show that there is an interaction between AgNPs and graphene. Trace detection of organic dyes is studied based on rGO/AgNPs hybrids as efficient surface enhanced Raman scattering platforms. It has been found that the suitable experiment parameter is crucial to trace detection of organic dyes molecules. This work is of importance in the practical application in device-design based on the SERS effect of noble metal/reduced oxide graphene (or oxide graphene) hybrids.