A New Allotrope of Carbon—Graphdiyne (g‐C_nH_2n−2) Boosting with Mn_0.2Cd_0.8S form S‐Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution

Abstract

As a new 2D carbon hybrid material, graphdiyne has attracted much attention due to its good conductivity, adjustable electronic structure, and special electron transfer enhancement properties. It has great potential in the field of hydrogen evolution by photocatalytic water splitting due to its special properties. In this paper, layered graphdiyne is prepared by crosscoupling method, using CuI instead of typical copper film as catalyst. Graphdiyne/CuI is used to modify Mn0.2Cd0.8S (MCS) solid solution for the first time, which greatly improves the optical properties and hydrogen production performance of the photocatalyst. The S‐scheme heterojunction constructed between graphdiyne and MCS greatly improves the transfer rate of photoinduced electrons. In addition, the results of fluorescence spectra and photoelectrochemical tests show that the nanocomposites have longer carrier lifetime, lower recombination rate, faster carrier migration rate, and lower hydrogen evolution overpotential. Therefore, the hydrogen evolution rate of the MnCdS/graphdiyne/CuI with the best performance can reach 9.904 mmol g−1 h−1, which is 4.02 times of that of pure MCS. This work not only proposes the possible mechanism of photocatalytic hydrogen production but also provides an important strategy for the application of graphdiyne in the field of photocatalytic hydrogen production.

In Situ X-ray Photoelectron Spectroscopy (XPS) Demonstrated Graphdiyne (g-CnH2n–2) Based GDY-CuI/NiV-LDH Double S-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution

“…As shown in Figure a, the absorption peak of GDY can be seen, where 2925 cm –1 is owed to the tensile vibration of CH 2  . The absorption peak of 2191 cm –1 is a conjugated diyne bond formed by sp hybridization, which can be owed to CC, but is weak due to the high symmetry of GDY . In Figure b, the absorption peak at 2359 cm –1 is owed to the OCO bond vibration displayed by the absorption of CO 2 by the catalyst .…”

“…27 The absorption peak of 2191 cm −1 is a conjugated diyne bond formed by sp hybridization, which can be owed to � C�C�, but is weak due to the high symmetry of GDY. 28 In Figure 3b, the absorption peak at 2359 cm −1 is owed to the O�C�O bond vibration displayed by the absorption of CO 2 by the catalyst. 29 For the original NiV-LDH, the absorption peaks at 1644 and 3444 cm −1 can be owed to the stretching between the hydrotalcite layers and the stretching of water molecules between the layers.…”

Rational Construction of Z‐Scheme Charge Transfer Based on 2D Graphdiyne (g‐CnH2n−2) Coupling with Amorphous Co3O4 Quantum Dots for Efficient Photocatalytic Hydrogen Generation

“…A distinct weak and broad characteristic peak at 23° is observed for GDY, which is indexed to the (002) plane, and the (002) plane is the characteristic plane belonging to the typical amorphous carbon materials. [56,57] Figure 2b demonstrates the XRD profiles of the GDY/CQDs composites with different content of GDY (10%, 15%, 20%, 30%, and 40%), all GDY/CQDs samples present similar diffraction peaks and can be observed in the feature peak of CQDs at 2θ = 36.8 o , declaring that the import of GDY does not alter the crystal structure for CQDs. Furthermore, no other peaks are detected in all composites declaring that the purity of the catalysts is very high.…”

Graphdiyne-based photocatalysts for solar fuel production

“…129 These advantages contribute to the excellent activities of graphdiyne-based photocatalysts in photocatalytic hydrogen evolution. 130–132…”

“…129 These advantages contribute to the excellent activities of graphdiyne-based photocatalysts in photocatalytic hydrogen evolution. [130][131][132] For instance, Li et al synthesised a graphdiyne/CuBr composite using CuBr as a substrate for photocatalytic hydrogen evolution. 133 Due to the suitable band arrangement between graphdiyne and CuBr, a p-n heterojunction is formed between them.…”