Highly Dispersed NiCo₂O₄ Nanodots Decorated Three-Dimensional g-C₃N₄ for Enhanced Photocatalytic H₂ Generation

Abstract

NiCo2O4 nanodots decorated graphitic carbon nitride (g-C3N4) heterojunction was synthesized based on the energy band matching theory for efficient photocatalytic hydrogen evolution reaction under simulated solar irradiation. NiCo2O4 species (E g = 1.77 eV) are uniformly anchored on the surface of g-C3N4 for the formation of NiCo2O4/g-C3N4 heterojunction to enhance the light response of the hybrid catalyst. The NiCo2O4/g-C3N4 heterojunction generates more structure defects, favoring the photocatalysis by accelerating the separation and transfer of the photoexcited electrons and holes and suppressing the recombination of the photoinduced carries. At the heterojunction interface, the photogenerated electrons transfer from the conduction band of NiCo2O4 to that of g-C3N4, while the photogenerated holes transfer from the valence band of g-C3N4 to that of NiCo2O4, making more active electrons participate in the generation of hydrogen. Compared with the pristine g-C3N4 and NiCo2O4, a NiCo2O4/g-C3N4 heterojunction sample (NC-6%) shows a hydrogen generation rate at 462.4 μmol·g–1·h–1, reaching 2.2 times and 400 times higher than that of g-C3N4 and NiCo2O4, respectively.

Multifunctional WO3/NiCo2O4 heterojunction with extensively exposed bimetallic Ni/Co redox reaction sites for efficient photoelectrochemical water splitting

“…The optical characteristics of prepared samples are compared by the UV‐vis curves displayed in Figure 6. The phenomenon is clearly presented that only light with a wavelength within about 460 nm is absorbed by pristine WO 3 , which demonstrates the performance of visible light photoresponse needs to be improved [48] . However, the pure NiCo 2 O 4 shows the wider absorption range of visible light to 475 nm.…”

“…As a spinel type binary metal oxide and p‐type semiconductor, NiCo 2 O 4 has been widely used in electrocatalysis with the properties of abundant reserves, excellent conductivity and low cost [47,48] . Furthermore, the abundant redox couples of Ni 2+ /Ni 3+ and Co 2+ /Co 3+ contained in NiCo 2 O 4 not only lead to higher electrical conductivity than NiO and Co 3 O 4 , [49–51] but also induce the potential of co‐catalyst in the PEC water splitting.…”

NH2-MIL-88B (FeαIn1−α) mixed-MOFs designed for enhancing photocatalytic Cr(vi) reduction and tetracycline elimination

“…27,28 Photocatalytic degradation is widely used in recent years because of mild reaction conditions, high efficiency, low cost and greenly. 20,[29][30][31] Metal-organic frameworks (MOFs), as a class of crystalline inorganic-organic hybrid materials, are composed of the interconnection between metal centers and multidentate organic ligands. 32,33 MOFs have been valued by researchers in the eld of photocatalysis 34,35 due to the inherent large specic surface area, uniform and adjustable pore structure, and abundant active sites.…”

Nanocarbon-Enhanced 2D Photoelectrodes: A New Paradigm in Photoelectrochemical Water Splitting

“…Commonly, ternary metal oxide is often defined as an oxide matrix consisting of two different metal ions. Compared with binary oxides, such as TiO 2 [160], ZnO [161], and WO 3 [162,163], ternary metal oxides possess rich and tunable compositions, which leads to controllable atomic and electronic structures as photoelectrodes with tunable light absorption [164,165]. In previous reviews [166][167][168], ternary BiVO 4 -related photoelectrodes have been summarized and discussed; hence, 2D BiVO 4 as a common supporting material in PEC systems is not discussed further.…”