Biomolecule-assisted synthesis of defect-mediated Cd_1−xZn_xS/MoS₂/graphene hollow spheres for highly efficient hydrogen evolution

Abstract

Moderate efficiency and the utilization of noble metal cocatalysts are the key factors that restrict the large-scale application of photocatalytic hydrogen production. To develop more efficient photocatalysts based on earth abundant elements, either a new material strategy or a fundamental understanding of the semiconductor/cocatalyst interfaces is highly desirable. In this paper, we studied the feasibility of in situ formation of defect-rich cocatalysts on graphene-based photocatalysts. A facile biomolecule-assisted strategy was used to self-assmble Cd 1Àx Zn x S/MoS 2 /graphene hollow spheres. The defect-mediated cocatalyst and synergetic charge transfer around heterostructured interfaces exhibit a significant impact on the visible-light-driven photocatalytic activity of multicomponent solid solutions. With engineered interfacial defects, Cd 0.8 Zn 0.2 S/MoS 2 /graphene hollow spheres exhibited a 63-fold improved H 2 production rate, which was even 2 and 3.8 times higher than those of CdS/MoS 2 /graphene hollow spheres and Cd 0.8 Zn 0.2 S/Pt. Therefore, our research provides a promising approach for the rational design of high-efficiency and low-cost photocatalysts for solar fuel production.

An Efficient and Stable MoS2/Zn0.5Cd0.5S Nanocatalyst for Photocatalytic Hydrogen Evolution

“…[31,43] The high-resolutionc ore spectrum of Zn shows two strong symmetricals pin-orbit peaks at 1021.3 and 1044.4 eV,w hich are assigned to Zn 2p 3/2 and Zn 2p 1/2 respectively,c onsistent with the previousr esultsf or Zn 2 + ( Figure S7 bi nt he Supporting Information). [32,43,44] Figure S7 ci nt he Supporting Information shows two peaks at 405.0 and 411.8 eV attributed to binding energies of Cd 3d 5/2 and Cd 3d 3/2 ,r espectively,c orresponding to the Cd 2 + state. [45,46] Figure S7 di nt he Supporting Information shows Mo 3d 5/2 and Mo 3d 3/2 peaks at 228.6 and 232.1 eV, respectively,w hicha re typical for Mo 4 + .…”

“…As shown in Figure S7 a (Supporting Information), the survey spectrum of 5 wt % MoS 2 /Zn 0.5 Cd 0.5 S indicates the existence of Zn, Cd, Mo, S, C, and O elements. The O peak is due to the absorption of oxygen on the surface of the sample on exposure to the atmosphere . In addition, the XPS spectrum of 5 wt % MoS 2 /Zn 0.5 Cd 0.5 S was consistent with the typical spectra of Zn 0.5 Cd 0.5 S and MoS 2 reported in the literature .…”

“…The O peak is due to the absorption of oxygen on the surface of the sample on exposure to the atmosphere . In addition, the XPS spectrum of 5 wt % MoS 2 /Zn 0.5 Cd 0.5 S was consistent with the typical spectra of Zn 0.5 Cd 0.5 S and MoS 2 reported in the literature . The high‐resolution core spectrum of Zn shows two strong symmetrical spin–orbit peaks at 1021.3 and 1044.4 eV, which are assigned to Zn 2p 3/2 and Zn 2p 1/2 respectively, consistent with the previous results for Zn 2+ (Figure S7 b in the Supporting Information) .…”

“…In addition, the XPS spectrum of 5 wt % MoS 2 /Zn 0.5 Cd 0.5 S was consistent with the typical spectra of Zn 0.5 Cd 0.5 S and MoS 2 reported in the literature . The high‐resolution core spectrum of Zn shows two strong symmetrical spin–orbit peaks at 1021.3 and 1044.4 eV, which are assigned to Zn 2p 3/2 and Zn 2p 1/2 respectively, consistent with the previous results for Zn 2+ (Figure S7 b in the Supporting Information) . Figure S7 c in the Supporting Information shows two peaks at 405.0 and 411.8 eV attributed to binding energies of Cd 3d 5/2 and Cd 3d 3/2 , respectively, corresponding to the Cd 2+ state .…”

Design of Heterostructured Hollow Photocatalysts for Solar‐to‐Chemical Energy Conversion

“…As mentioned previously, heterostructures can be constructed by more than two types of building blocks. Cd 1‐ x Zn x S/MoS 2 /graphene hollow spheres were fabricated through a biomolecule‐assisted one‐pot reaction . The heterostructured Cd 0.8 Zn 0.2 S/MoS 2 /graphene hollow spheres show a photocatalytic hydrogen generation rate of 2.97 mmol h −1 g −1 .…”