In situ growth of CuS nanoparticles on g-C₃N₄ nanosheets for H₂ production and the degradation of organic pollutant under visible-light irradiation

Abstract

The solar-to-fuel conversion using a photocatalyst is an ideal method to solve the energy crisis and global warming. In this contribution, photocatalytic H 2 production and organic pollutant removal using g-C 3 N 4 / CuS composite was demonstrated. Well dispersed CuS nanoparticles (NPs) with a size of about 10 nm were successfully grown on the surface of g-C 3 N 4 nanosheet via a facile hydrothermal method. The asprepared g-C 3 N 4 /CuS nanocomposite at an optimized loading exhibited a much higher visible light photoactivity, giving up to 2.7 times and 1.5 times enhancements in comparison to pure g-C 3 N 4 for photocatalytic H 2 production and methylene orange (MO) degradation, respectively. These enhanced photocatalytic activities are attributed to the interfacial transfer of photogenerated electrons and holes between g-C 3 N 4 and CuS, which leads to effective charge separation on both parts. That is, under the visible light irradiation, electrons in the valence band (VB) of g-C 3 N 4 can directly transfer to the CuS NPs, which can act as an electron sink and co-catalyst to promote the separation and transfer of photogenerated electrons, thus significantly improving the photocatalytic efficiency. Fig. 4 (A) The photodegradation activities of MO as a function of time over different photocatalysts under visible light irradiation (>420 nm), (B) the value of the rate constant k of the photodegradation of MO in the presence of as-prepared photocatalysts, (C) cycling runs of g-C 3 N 4 / 0.5 wt% CuS photocatalyst in the photodegradation of MO under visible light irradiation (>420 nm), and (D) photodegradation of MO in the presence of three types of scavengers and g-C 3 N 4 /0.5 wt% CuS photocatalyst under visible light irradiation (>420 nm).This journal is

Facile One‐Pot Synthesis and Enhanced Photocatalytic Performances of Ternary Metal Sulfide Composite g‐C3N4/Cu3SnS4

“…[58,59] Meanwhile, the electrons on the CB of CTS can reduce O 2 to H 2 O 2 (O 2 /H 2 O 2 = 0.695 eV/NHE), and then, H 2 O 2 is further reduced to •OH radicals (H 2 O 2 /OH = 0.32 eV/NHE) by the electrons on the CB (Equations 6, 7). [49,56,57] The h + holes, as well as •O 2…”

“…The potential of the valence band ( E VB ) and conduction band ( E CB ) of g‐C 3 N 4 and CTS can be calculated by empirical formulas: [49] …”

“…where X is the electronegativity of the semiconductor, and E e is the energy of free electrons via hydrogen (about 4.5 eV/NHE). The X values of CTS and g‐C 3 N 4 are 5.07 eV, [31] and 4.64 eV, [49] respectively. Therefore, the E VB and E CB of CTS are 1.32 eV/NHE and −0.17 eV/NHE, and the E VB and E CB of g‐C 3 N 4 are 1.49 eV/NHE and −1.21 eV/NHE.…”

Hollow Structured Metal Sulfides for Photocatalytic Hydrogen Generation

“…However, the improvement and development of this semiconductor material towards practical application is limited due to the fast recombination of the photogenerated electron‐hole pairs of CuS. Previous reports on the formation of heterojunctions between CuS‐based and other semiconductor materials such as ZnS, ZnO, and TiO 2 , wherein copper sulfides are employed as co‐catalyst, have shown promising results including the slowed recombination of photogenerated electrons‐holes which enhanced the photocatalytic efficiency of the materials …”

Designing 2D–2D g-C3N4/Ag:ZnIn2S4 nanocomposites for the high-performance conversion of sunlight energy into hydrogen fuel and the meaningful reduction of pollution

“…15 Two-dimensional (2D) g-C 3 N 4 can offer an extended specic surface area, reveal supplemental exposed active sites, provide an easier approach and diffusion paths for both ions and electrons. [16][17][18] However, a single component cannot satisfy all requirements because of the low efficiency of solar energy conversion, the less-than-ideal solar light response range, the low ability for charge separation/ transfer, and reduced photocatalytic stability. 19,20 To solve the aforementioned problems, some typical protocols have been conceived to enhance the photocatalytic process.…”