Rational design of CdS@ZnO core-shell structure via atomic layer deposition for drastically enhanced photocatalytic H2 evolution with excellent photostability

Abstract

Rational design of CdS@ZnO core-shell structure via atomic layer deposition for drastically enhanced photocatalytic H evolution with excellent photostability, Nano Energy, http://dx.doi.org/10. 1016/j.nanoen.2017.06.047 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. number of deposition cycles, and the obtained CdS@ZnO with 100 ALD deposition cycles displays the optimal photocatalytic H 2 evolution rate of 11.36 mmol/g/h. WhenPt and PdS are used as the co-catalysts, the H 2 evolution rates are further enhanced to 71.39 and 98.82 mmol/g/h, respectively, which are 4.1 and 5.7 times higher than the highest reported value (17.40 mmol/g/h) among CdS-ZnO catalyst systems. Detailed characterization reveals that the drastically enhanced photocatalytic activity can be attributed to not only efficient space separation of the photo-induced electrons and holes resulted from the formation of a direct Z-scheme photocatalytic system between crystalline ZnO and CdS, but also the intimate contact at molecular scale between the two semiconductors. Due to the coverage of ALD-prepared crystalline ZnO shell on CdS core, the CdS@ZnO core-shell structures exhibit excellent photostability. Graphical abstract3 / 31

Fabrication of ZnO/Red Phosphorus Heterostructure for Effective Photocatalytic H2 Evolution from Water Splitting

“…To investigate the separation and transfer efficiency of the photo-generated carriers over the ZnO/RP heterostructures, the PL spectra of the as-synthesized samples are shown in Figure 5 a. It is known that the photo-induced electron in the conduction band will recombine with the hole at the valence band, leading to the emission of fluorescence [ 32 ]. Therefore, the quench of the PL spectra usually indicates the inhibition of the recombination for charge carriers, implying the separation of photo-induced electrons and holes.…”

“…XPS analysis was performed to investigate the chemical states of pure ZnO, ZRP-5 and RP, as shown in Figure 6 b. The P 2 p spectra of ZRP-5 and RP are shown in Figure 6 c. For the RP, the spectrum shows that its surface is mainly composed of P 0 atoms (129.8 eV) and a certain amount of P 5+ atoms (134.47 eV) [ 32 , 41 ]. For ZRP-5, there are two peaks of P 2 p located at 133.5 and 128.5 eV, which is consistent with P 5+ and P 0 , respectively.…”

“…ZRP-5 it presents double peaks at 1021.8 and 1044.9 eV. These two peaks shift to the higher binding energies, indicating the strong interaction between ZnO and RP and the possible transfer of photogenerated charge carriers [ 32 ]. The XPS results reveal the strong interaction and chemical bonding between ZnO and RP, which are believed to result in the fast immigration of charge carriers and the separation of photo-excited electron–hole pairs.…”

A Novel Charge Transfer Channel to Simultaneously Enhance Photocatalytic Water Splitting Activity and Stability of CdS

“…However, more reported application of CdS is severely limited owing to suffering from poor carrier separation, severe surface recombination, and photocorrosion. To solve these issues, several strategies have been explored to address these shortcomings, including using noble metal as a cocatalyst to boost the kinetics of water reduction, and constructing a heterojunction by coupling CdS with other semiconductors (such as TiO 2 , ZnO, ZnS, WO 3 , PbS, Ag 2 S, Al 2 O 3 , WS 2 , and MoS 2 ).…”

Enhanced hydrogen evolution from water splitting based on ZnO nanosheet/CdS nanoparticle heterostructures

“…As a new clean and efficient energy source, hydrogen has attracted wide attention because of its high combustion heat and clean combustion products. [1][2][3][4][5][6] In 1972, Fujishima rst achieved hydrogen production through the photocatalytic decomposition of water using a titanium dioxide semi-conductor as an electrode under ultraviolet irradiation. 7 Since then, hydrogen evolution from water splitting based on photocatalytic technology has been widely and deeply studied.…”