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Designing efficient non-precious electrocatalysts to boost water splitting for green energy is a worthy and crucial objective, while it is still an enormous challenge. Herein, single-phase Ni5P4 ultrathin porous nanosheets grown on Ni foam constructed using the three-dimensional single-phase hierarchical nanoflower Ni5P4 (defined as 3D SHF-Ni5P4) were assembled via a simple hydrothermal and phosphating process in an enclosed space. Benefitting from the special structure and morphology of 3D hierarchical porous ultrathin nanosheets, as well as their increasing number of active sites, the 3D SHF-Ni5P4 exhibited outstanding performance with low overpotentials of 180 mV and 106 mV for achieving a current density of 10 mA cm−2 in 1 M KOH toward both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), and the Tafel slopes were 54 mV dec−1 and 79 mV dec−1, respectively. The overall water separation setup, using 3D SHF-Ni5P4 as both the cathode and anode in 1.0 M KOH, achieved a current density of 10 mA cm−2 at a low voltage of 1.47 V, which surpasses that of the commercial Pt C/NF‖‖RuO2/NF (1.52 V). This work highlights an achievable strategy for the controllable fabrication of a 3D single-phase hierarchical nanoflower Ni5P4 electrocatalyst, constructed with ultrathin porous nanosheets containing plenty of active sites. It provided new insights into developing cost-effective single-phase electrocatalysts towards green energy by water splitting. [ABSTRACT FROM AUTHOR]

The development of excellent photocatalysts for hydrogen evolution is of great significance to solving the global energy crisis. In this work, a novel 3D hierarchical CdS/NiAl-LDH photocatalyst was fabricated by a facile electrostatic assembly strategy, which was composed of 1D CdS nanorods and 3D flower-like NiAl-LDH microspheres. Under the visible irradiation, the CNA-20 hierarchical photocatalyst presents the optimum hydrogen evolution rate achieved to 3.24 mmol g−1 h−1, which is improved 6.23-fold in comparison with the pure CdS. Through the analysis of energy band structures and first-principles calculation, the type-Ⅱ charge transfer mechanism was proposed. Driven by the built-in electric field, as well as the effect of intimate interface contact of CdS and NiAl-LDH, the photogenerated charge could be achieved rapidly separate and migrate, which effectively promotes the H 2 evolution. This well-designed synergistic 1D/3D interface interaction and provides an economic approach to rationally developing metal-free photocatalysts for hydrogen production. [Display omitted] • A novel 3D hierarchical CdS/NiAl-LDH photocatalyst was fabricated by the electrostatic self-assembly strategy. • The CdS/NiAl-LDH photocatalyst displays excellent H 2 production activity and stability. • DFT calculations helped to explain the charge transfer at the heterojunction interface between CdS and NiAl. • A possible charge transfer mechanism during the photocatalytic H 2 evolution was proposed. [ABSTRACT FROM AUTHOR]