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Exploration of cost-efficient and high-performance photocatalyst for H2 evolution by using a facile approach is of great importance. In this manuscript, a facile one-pot method was employed to fabricate MoS2/CdS heterostructures with MoS2 intimately grown on the surface of CdS resulting in the formation of well-defined heterostructures. Screen experiment reveals the optimized photocatalytic H2 evolution performance of MoS2/CdS is far exceeding that of pristine CdS by a factor of more than 162. The outstanding performance can be ascribed to the formation of heterostructures which accelerate charge transportation and separation, and the MoS2 serving as a cocatalyst for the decrease of H2 overpotential. Moreover, the photocatalytic mechanism of the MoS2/CdS was carefully investigated, which contributes to the deep understanding of the photocatalytic process and the designation of other low-cost and high-efficient photocatalyst.

Photocatalytic water splitting is considered to be a green H2 generation approach and has potential to be applied in the future. As a photocatalytic active material for H2 evolution, CdS is a good candidate. However, the pristine CdS still suffers from low efficiency and poor stability. To address those issues, we developed noble-metal-free CdS@MoS2 core-shell nanoheterostructures which exhibit outstanding photocatalytic H2 evolution performance thus far with rate of 62.55 mmol g−1 h−1, which exceeds that of pristine CdS by a factor of 148. Meanwhile, the photocatalytic stability can be well retained with no deterioration of activity in 24 h reaction. The excellent performance can be reasonably attributed to the low crystallinity of MoS2 with numerous active sites provided, and the band alignment of CdS and MoS2 as determined by valence band-XPS and Mott-Schottky plots analysis, which significantly promotes charge transportation and separation. The enhanced photocatalytic stability here should be ascribed to the intimate growth of MoS2 shells which significantly passivate the surface trap states of CdS cores and thus the photocorrosion is remarkably retarded. This novel strategy will inspire the fabrication of other photocatalytic systems, and may high-efficient photocatalysts be obtained.

In the present work, nitrogen-doped mesoporous carbon nanosheets (NMCNs) are prepared and extensively investigated for the oxygen reduction reaction. Initially, by using dual templates, viz. graphene oxide and a cationic surfactant, silica films (thickness: 1.0 nm) are synthesized and characterized using transmission electron microscope (TEM), nitrogen adsorption-desorption (N2 ad/des) measurements, and small-angle X-ray diffraction (SA-XRD). Morphology and structure of silica evolve along with graphene oxide concentration, while the co-operative assembly and the final structure are determined by the electrostatic interaction between the dual templates. The effect of silica template on the resultant NMCNs is investigated physicochemically by photoelectron spectroscopy (XPS), TEM, N2 ad/des and electrochemically by cyclic voltammetry (CV), and linear sweep voltammetry (LSV). NMCNs are featured of a high content of nitrogen dopant, high specific surface area (SSA) and ultrathin thickness (1.5 nm), favoring catalysis and facilitating the mass transport of the reactive species. From the electrochemical tests, it is confirmed that NMCNs yield a high oxygen reduction reaction (ORR) electrocatalytic activity in acid and alkaline environment; this activity is similar or even better as compared with the one measured over carbon supported platinum commercial catalyst (40 wt % Pt/C).

Quality of interfaces is a key factor determining photoexcited charge transfer efficiency, and in turn photocatalytic performance of heterostructure photocatalysts. In this paper, we demonstrated CdS-MoS2/RGO-E (RGO-E: reduced graphene oxide modified by ethylenediamine) nanohybrid synthesized by using a facile one-pot solvethermal method in ethylenediamine, with CdS nanoparticles and MoS2 nanosheets intimately growing on the surface of RGO. This unique high quality heterostructure facilitates charge separation and transportation, and thus effectively suppressing charge recombination. As a result, the CdS-MoS2/RGO-E exhibits a state-of-the-art H2 evolution rate of 36.7 mmol g−1 h−1 and an apparent quantum yield of 30.5% at 420 nm, which is the advanced performance among all the same-type photocatalysts (see Table S1), and far exceeding that of bare CdS by higher than 104 times. This synthesis strategy gives an inspiration for the synthesis of other compound catalysts, and higher performance photocatalyst may be obtained.