Constructing highly efficient and cost-effective photocatalyst system has been a big challenge for photocatalysis . Herein, CdS nanosphere ( N -CdS), hollow CdS (H-CdS) and a series of H-CdS@NiCoP core–shell nanospheres have been successfully prepared via a facile hydrothermal method . The activity test showed that H-CdS exhibited higher photocatalytic activity (3.34 mmol g -1 h −1 ) compared with N -CdS (0.99 mmol g -1 h −1 ) under visible light irradiation (λ ≥ 420 nm), suggesting that hollow structure could effectively improve photocatalytic activity. Moreover, the H-CdS@NiCoP-7 wt% displayed a maximum photocatalytic H 2 evolution rate of 13.47 mmol g -1 h −1 , which was about 4 times and 2.5 times higher than that of pristine H-CdS and H-CdS@Pt-3 wt%, respectively. Furthermore, H-CdS@NiCoP-7 wt% exhibited a good stability during 20 h test. The physicochemical properties were characterized by XRD , SEM , TEM, XPS , UV–vis DRS , PL and photoelectrochemical technique. The results showed that NiCoP addition can construct p-n junction with H-CdS and effectively promote the charge transfer from CdS to NiCoP, which improved the photocatalytic hydrogen evolution activity. This work revealed that NiCoP could react as an excellent co-catalyst for enhancing H-CdS photocatalytic activity.
Junnan Tao,Mingyuan Wang,Xiangzhao Zhang,Lei Lu,Hua Tang,Qinqin Liu,Shuangying Lei,Guanjun Qiao,Guiwu Liu
Energy band matching coupled with intimate interface in a heterojunction is the prerequisite for achieving the separation of photogenerated carriers. Herein, 0D CdS nanospheres were uniformly anchored in 3D flower-like CoAl layered double hydroxide (CoAl-LDH) spheres via a hydrothermal process. The unique porous structure and abundant hydrophilic groups can significantly promote the interactions between catalyst and solutions and thus facilitate the photocatalytic reaction. The appropriately staggered band structures can trigger the formation of S-scheme heterojunction, and the tight connection between the CdS and CoAl-LDH offers more charge transport channels, thereby accelerating the charge transfer. The optimized CdS/CoAl-LDH nanohybrid presents a photocatalytic hydrogen evolution of 6.19 mmol/g/h and tetracycline hydrochloride (TC) degradation efficiency of 92.2 % in 50 min. Moreover, the Cd 2+ ion concentration measured by ICP-OES verifies the alleviation of photocorrosion, and the DFT calculations further demonstrate the higher hydrophilia, lower H 2 absorption energy and stronger charge interactions of CdS/LDH hybrid. This work provides a feasible strategy to efficiently utilize the photoinduced carries by constructing a highly hydrophilic S-scheme heterojunction.
A "signal on" aptasensor was fabricated for chlorpyrifos detection by a highly efficient electrochemiluminescence resonance energy transfer (ECL-RET) strategy between MoS 2 /CdS nanospheres and silver/carbon quantum dots (Ag/CQDs). Compared with the conventional MoS 2 /CdS nanosheets, the MoS 2 /CdS nanospheres have a larger specific surface area and electron density, which makes the catalytic effect on K 2 S 2 O 8 stronger and has higher luminescence intensity. As a receptor, through the synergistic effect of Ag NPs and CQDs, it has a very wide absorption band between 300 and 600 nm. The absorption band and the emission spectrum of MoS 2 /CdS completely overlap, and the high quantum yield of Ag/CQDs can achieve efficient energy resonance transfer. The proposed ECL aptasensor provided a linear range from 10 nM to 1.0 fM for chlorpyrifos detection and the detection limit of 0.35 fM (S/N = 3) under optimal experimental conditions. The method was successfully applied to the detection of chlorpyrifos in fruit and vegetable samples with satisfactory results.
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