Ultrafast synthesis of Cu2O octahedrons inlaid in Ni foam for efficient alkaline water/seawater electrolysis

Zeolite-Templated Carbons Supported Rh and Ru Electrocatalysts for Highly Active Hydrogen Evolution Reaction

Here, we report the systematical synthesis of zeolite-templated carbon (ZTC) supported Ru and Rh mono- or bi-metallic electrocatalysts towards hydrogen evolution reaction (HER). The zeolite A or ZSM-5 derived ZTC supports and metal sites were adjusted, and all electrocatalysts outperformed the commercial Pt/C electrocatalyst for HER performance. In particular, the RhRu/(ZTC/ZSM5) sample exhibited superior catalytic performance with the overpotential of 24.8 mV@10 mA ⋅ cm-2, and outstanding stability with 1 mV drop after 20000 cyclic voltammetry circles. This work offers a simple impregnation method for the synthesis of highly performed HER electrocatalysts supported on porous zeolite-templated carbon.

Nanoflower-like FeVNi3S2-xas efficient electrocatalyst for alkaline oxygen evolution reaction

The development of low cost efficient catalysts for oxygen evolution reaction (OER) is still a obstacle to realize the commercialization of electrocatalytic water splitting. Herein, interface engineering and heteroatom doping is adopted to synthesize iron and vanadium doped nickel sulfide on nickel foam via hydrothermal method followed by hydrogen treatment to create sulfur defects. The optimized nanoflower-like FeVNi3S2-x/NF is an efficient OER electrocatalyst that outperforms many of the reported transition metals catalysts. Benefiting from abundant sulfur defects and the synergistic effect of heteroatom doping, FeVNi3S2-x/NF exhibits an ultralow overpotential of 230 mV to reach a current density of 100 mA cm-2, a rapid reaction kinetics with a small Tafel slope of 46.6 mV dec-1, and a stable long-term durability in 1 M KOH. Experimental results and characterizations confirm that sulfur vacancies together with the synergistic effect from multiple heteroatom doping can effectively regulate the electronic structure, resulting in increased electrical conductivity and electrochemically active surface area, thus enhancing OER performance. Furthermore,in situRaman spectroscopy reveals that, the reconstitution amorphous nickel oxyhydroxide (NiOOH) on the catalyst surface is responsible for catalyzing the OER reaction. This work represents a promising methodology to synthesize low-cost and highly active OER electrocatalysts.

Elevating the d-Band Center of Ni3S2 Nanosheets by Fe Incorporation to Boost the Oxygen Evolution Reaction

Many attempts have been made to enhance the relatively poor electrochemical activity of Ni₃S₂ for the oxygen evolution reaction (OER) by elevating the d-band center. Unfortunately, only limited success has been encountered thus far. Owning to the lower electronegativity and one less 3d electron relative to Ni, Fe shows great potentials in upshifting the overall d-band center of Ni₃S₂ when incorporating into its crystal structures. Herein, to enhance the intrinsic activity by elevating the d-band center, Ni₃S₂ nanosheets incorporated with suitable Fe content have been fabricated by a facile one-step solvothermal method. The obtained Fe-incorporated Ni₃S₂ catalyst exhibits an outstanding OER performance in alkaline media, only requiring 244 mV overpotential (with a reduction of 210 mV compared to Ni₃S₂) at 50 mA cm^-2 in 1 M KOH and without obvious degradation after sustaining for a 60 h test at a voltage above 1.5 V. Ultraviolet photoemission spectroscopy and density functional theory calculations consistently demonstrate that the superior performance of Fe-incorporated Ni₃S₂ is attributed to the upshift of the d-band center on neutralizing the electron densities of Ni, which optimize greatly the adsorption energy of the intermediate (OOH*) in the rate-determining Volmer step.

Hierarchical Design in Nanoporous Metals

Hierarchically porous metals possess intriguing high accessibility of matter molecules and unique continuous metallic frameworks, as well as a high level of exposed active atoms. High rates of diffusion and fast energy transfer have been important and challenging goals of hierarchical design and porosity control with nanostructured metals. This review aims to summarize recent important progress toward the development of hierarchically porous metals, with special emphasis on synthetic strategies, hierarchical design in structure-function and corresponding applications. The current challenges and future prospects in this field are also discussed.