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Photoelectrically coupling water splitting at high current density is a promising approach for the acquisition of green hydrogen energy. However, it places significant demands on the photo/electrocatalysts. Herein, rare earth elements doping NiMoO4‐based phosphorus/sulfide heterostructure nanorod arrays (RE‐NiMo‐PS@NF [RE = Y, Er, La, and Sc]) are obtained for solar‐enhanced electrocatalytic water splitting at high current densities. The results of the experiment and density‐functional theory studies illustrate that the Y element as a dopant not only makes the NiMoP2/NiMo3S4/NiMoO4 heterostructure exhibit excellent solar‐enhanced electrocatalytic activity (hydrogen evolution reaction [HER]: η1000 = 211 mV, oxygen evolution reaction [OER]: η1000 = 367 mV) but also optimizes the heterostructure interfacial electron density distributions and HER free energy. In addition, Y‐NiMo‐PS@NF achieves 18.64% solar‐to‐hydrogen efficiency. This study not only provides a new way to synthesize heterostructure electrocatalysts but also inspires the application of solar enhancement strategies for high current density water splitting. [ABSTRACT FROM AUTHOR]

We have synthesized 10%Ce-NiMo-PS@NF using the strategy of simultaneous phosphatization and sulfidation strategy. It exhibits significant photo-enhanced electrocatalytic high-current–density activity. Furthermore, it exhibits an STH of 18.68% in a photoelectric coupled water splitting system. [Display omitted] • The Ce-doped NiMo-based phosphorus/sulfide heterostructure is synthesized. • 10%Ce-NiMo-PS@NF exhibits significantly high-current–density electrocatalytic performance under photo-enhanced conditions. • 10%Ce-NiMo-PS@NF exhibits an STH efficiency of 18.68% in a photoelectric coupled water splitting system. NiMo-based electrocatalysts are widely regarded as promising electrocatalysts for overall water splitting (OWS). However, to solve the problem of slow reaction kinetics and serious deactivation at high current density, the reasonable design of NiMo-based electrocatalysts is still a great challenge. In this work, NiMo-based phosphorus/sulfide heterostructure electrocatalysts with different Ce doping ratios (5%/10%/15%Ce-NiMo-PS@NF) have been designed using the combination of cation doping and heterostructure engineering. The doping of Ce not only changes the electronic environment of the heterostructure, accelerates the electron transport at the heterostructure interface, but also enhances the light absorption capacity of the heterostructure. The experimental results show that 10%Ce-NiMo-PS@NF has the best photo-enhanced electrocatalytic activity (hydrogen evolution reaction (HER): η 1000 = 250 mV, oxygen evolution reaction (OER): η 1000 = 242 mV, and OWS: E 1000 = 1.864 V). In addition, its solar-to-hydrogen (STH) efficiency in a photoelectric coupled water splitting system is as high as 18.68%. This study not only provides a new method for the synthesis of new heterostructure electrocatalysts, but also provides a reference for the rational use of light energy to enhance electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Self-supported FcNi-BDC-H 2 O 2 electrocatalysts were synthesized on nickel foam via a one-step solvothermal technique. The electrocatalysts demonstrated improved performance in both OER and UOR, attributed to the ligands competition and H 2 O 2 etching. [Display omitted] Two-dimensional metal–organic frameworks are considered to be promising electrocatalytic materials due to their ultrathin lamellar structure, ultrahigh porosity and large surface area, but there are still many challenges such as the embedding of organic ligands leading to low density of active sites and poor conductivity. Herein, we synthesize two-dimensional ferrocene-based metal–organic frameworks nanosheet electrocatalysts via the one-step hydrothermal hydrogen peroxide etching method. The prepared FcNi-BDC-H 2 O 2 /NF exhibits excellent oxygen evolution reaction performance with a current density of 100 mA·cm-2 at only 258 mV and a small driving potential of 1.542 V (10 mA·cm-2) is required to achieve overall water splitting. Significantly, an overall water-cracked cell using a solar cell assembly achieves the solar hydrogen conversion efficiency of 19.5%. The introduction of high electronegativity ferrocene and the etching of H 2 O 2 increase the Ni3+ content of FcNi-BDC-H 2 O 2 , and expose more unsaturated active sites, which improve the intrinsic activity of the catalysts and the mass transfer rate during the catalytic process. Moreover, the FcNi-BDC-H 2 O 2 /NF demonstrates significant urea oxidation reaction performance, achieving a potential of 1.35 V and producing 10 mA·cm-2. This study presents a viable approach to investigating highly efficient electrocatalysts for oxygen evolution reaction and urea oxidation reaction using MOF-based bifunctional catalysts. [ABSTRACT FROM AUTHOR]