Light-assisted synthesis MoSx as a noble metal free cocatalyst formed heterojunction CdS/Co3O4 photocatalyst for visible light harvesting and spatial charge separation

Cadmium Sulfide 3D Photonic Crystal with Hierarchically Ordered Macropores for Highly Efficient Photocatalytic Hydrogen Generation

Cadmium sulfide is a potential candidate for photocatalytic water splitting. However, CdS nanoparticles have a high recombination rate of photoinduced carriers induced by aggregation. Therefore, decreasing the recombination rate and increasing the migration rate of photogenerated carriers are essential to drive the development and application of CdS in hydrogen production. In this study, we design CdS with a three-dimensional ordered macroporous (3DOM) structure using polymethylmethacrylate as a template. It not only retains the excellent visible light response of CdS but also improves the easy recombination of photogenerated carriers in CdS nanoparticles by taking advantage of the unique ability of mass transfer, charge separation, and migration in the 3DOM structure. Meanwhile, the highly ordered periodic structure of 3DOM CdS can produce a slow photon effect of photonic crystals to obtain more photoinduced carriers. In particular, we found that a suitable stop-band position is beneficial to maximize the utilization of the slow photon effect. The photocatalytic hydrogen evolution rate of Pt-CdS is considerably improved after constructing the 3DOM structure. This study provides a new design strategy of ordered macroporous sulfide catalysts to achieve high photocatalytic activity.

Sensitivity of photoelctrocehmical aptasensor using spiral nanorods for detecting antiobiotic levels in experimental and real samples

Given increasing concern regarding antibiotic environmental contamination, there is immediate need to monitor antibiotic levels to effectively control pollution. In this study, we used a photoelectrochemical aptasensor based on TiO₂@MoS₂ spiral nanoarrays to detect chloramphenicol (CAP) in antibiotics. Nanoarrays were directly grown on fluorine-doped tin oxide (FTO) conductive glass with excellent biochemical stability, while aptamer-SH were immobilized by chemical binding on a synthetic TiO₂@MoS₂ nanoarray. Results show that the photocurrents were reduced in the presence of photoelectrochemistry associated with specific selection of aptamer for CAP. When the measurement of the fabricated nanomaterial chip was carried out using a three-electrode system, we found a highly specific and stable detection of chloramphenicol that ranged between 0.1 pM and 1 μM, with the detection limit of 0.1 pM. In addition, we obtained satisfactory results when real sample were used to validate the potential of photoelectrochemical (PEC) aptasensor for detecting chloramphenicol content in milk. Our results demonstrate that photoelectrochemical aptasensor is conducive to the development of less toxic multifunctional nanomaterials, making the biosensor more robust and environmentally friendly. Therefore, photoelectrochemical aptasensor can be widely applied in the field of environmental monitoring.

CoS2-decorated CdS nanorods for efficient degradation of organic pollutants

The heterostructure between CoS2 and CdS can improve the charge separation efficiency during photocatalysis and promote the generation of more OH and O2− radicals under light irradiation.

Superhydrophobic Self-Supporting BiOBr Aerogel for Wastewater Purification

This research was focused on the raw material level construction of bismuth oxybromide (BiOBr) catalysis-loaded 3D cross-linked network polyurethane (PU) foam via the in situ polymerization method. After modification of superhydrophobic polydivinylbenzene nanoparticles, the PU foam possessed excellent superhydrophobic stability. The larger selective absorption oil phase capacity depended on its macroporous structure, and the existence of catalyst BiOBr (the band gap energy was about 2.57 eV) among the PU foam played a crucial role in degrading water-soluble contaminants under visible light irradiation. In this article, the photocatalytic experiment results verify that it has remarkable recycle degradation ability (the degradation efficiency can reach ∼97%) and the capture experiments indicate that the uppermost active species is h⁺.

Constructing CuNi dual active sites on ZnIn2S4 for highly photocatalytic hydrogen evolution

Novel CuNi bimetal-modified ZnIn₂S₄ photocatalysts with enhanced photocatalytic hydrogen evolution performance have been explored. The possible mechanism of the synergistic effect and spillover effect between Cu and Ni were proposed.

Flexible photocatalytic membrane based on CdS/PMMA polymeric nanocomposite films: multifunctional materials

In this study, poly(methyl methacrylate) with different doping nano-cadmium sulfide (CdS/PMMA) is prepared and characterized. CdS/PMMA polymeric nanocomposite films were synthesized using solution casting methodology. SEM and XRD are used for structure analysis for the studied nanocomposite films. XRD revealed the amorphous domains of PMMA polymer, which increased with increasing CdS nanoparticle contents. SEM revealed the CdS dispersion within the PMMA matrix. CdS nanoparticles in the PMMA matrix are expected to be aggregated due to the casting technique. The optical energy gap is found to be decreased after the CdS addition. ε' and ε″ have the same behavior with the applied frequency. Maxwell-Wagner interfacial polarization is the responsible factor for higher values of ε'-ε″ at the higher frequencies. Electrical conductivity behavior σ_AC tends to obtain a constant value at lower frequencies that approach from its DC conductivity values. After doping PMMA with nano-CdS, an exponential increase after a critical frequency value and the values of σ_AC was also increased. Besides, a significant reduction in laser energy power is identified by the reduction of the output power. CdS/PMMA can attenuate the laser power due to its nonlinear effect. CdS/PMMA nanocomposite can act as a photocatalyst to improve the performance of the photodegradation of Rhodamine B (RhB). Among the different CdS/PMMA nanocomposite films, 3.33 wt% CdS/PMMA demonstrates the highest efficiency in visible photocatalysis of Rhodamine B. CdS/PMMA can be utilized as multifunctional materials use like laser optical limiting to reduce the power of laser sources and as a photocatalyst membranes.

Integrating CuInSe2 nanocrystals with polymeric carbon nitride nanorods for photocatalytic water splitting

Developing photocatalysts with improved photoactivity and efficiency has remained an enduring theme both fundamentally and technologically in the field of photocatalysis. Polymeric carbon nitride (CN) has been widely exploited as an earth-abundant photocatalyst for water redox reactions. Nevertheless, the limited visible-light utilization rate and the high recombination rate of photoinduced charge carriers give rise to the moderate photocatalytic reactivity of CN in water splitting. Herein, p-type CuInSe2 nanocrystals are prepared by a solvothermal approach and then immobilized with n-type CN nanorods through self-assembly and thermal treatment process, forming a CuInSe2/CN hybrid photocatalyst. Benefiting from the p-n heterojunction, a 3% CuInSe2/CN nanocomposite photocatalyst exhibits a three-fold increase in the hydrogen evolution rate (HER) compared to that of bare CN nanorods owing to the strengthened visible-light capturing capability and improved separation rate of photoexcited charge carriers. This work paves new avenues for the construction of p-n heterojunction photocatalysts for solar fuel production.

Nitridation of CoWO4/CdS Nanocomposite Formed Metal Nitrides Assisting Efficiently Photocatalytic Hydrogen Evolution

Nitridation of CoWO₄/CdS nanocomposite results in the formation of metal nitrides on the surface of CdS. The high electrical conductivity, appropriate binding energy for hydrogen, and Pt-like properties of the surface nitrides promote the H₂ evolution performance. Therefore, the optimal performance of nitrided CoWO₄/CdS (CoWO₄/CdS-N, 3650 μmol·h^-1·g^-1) is higher than that of Pt/CdS (2948 μmol·h^-1·g^-1).

Amorphous tungsten phosphosulphide-modified CdS nanorods as a highly efficient electron-cocatalyst for enhanced photocatalytic hydrogen production

Improving the utilization rate of photogenerated electrons generated by visible light excitation is an important factor to improve the activity of photocatalytic decomposition of water for hydrogen evolution.

Photochemical deposition of amorphous MoSx on one-dimensional NaNbO3–CdS heterojunction photocatalysts for highly efficient visible-light-driven hydrogen evolution

A novel ternary MoS_x–CdS–NaNbO₃ (MoS_x–CN) photocatalyst was successfully fabricated through a two-step method (hydrothermal synthesis and photo-deposition step).

Optimization of the facet structure of cobalt oxide catalysts for enhanced hydrogen evolution reaction

The three different exposed crystal planes of Co₃O₄ catalysts, in which the {112} and {011} planes with abundant Co³⁺ sites exhibited photocatalytic hydrogen evolution activity superior to that of the {001} plane.

Synthesis of a novel 2D zinc(ii) metal-organic framework for photocatalytic degradation of organic dyes in water

A novel 2D zinc(ii) metal-organic framework, formulated as [Zn(L)(H2O)]·H2O (1) (H2L = 4-(pyridine-4-yl) phthalic acid), has been successfully obtained under solvothermal conditions. This metal-organic framework (MOF) material exhibits efficient photocatalytic activity towards the degradation of organic dyes in the absence of any photosensitizer or cocatalyst. Its catalytic performance for rhodamine B (RhB) and methyl orange (MO) degradation was superior to most reported MOFs with a degradation efficiency of 98.5% for RhB and 83.8% for MO within 120 min in the absence of H2O2, which could be attributed to its high efficiency in generating ·O2- (an effective oxidant for the degradation of dyes). The possible mechanism of the reaction was discussed in detail. In addition, 1 shows stable catalytic efficiency after five reaction cycles, which indicates that 1 exhibits efficient catalytic activity and good reusability toward the degradation of organic dyes, enabling it to be a potential candidate for environmental governance.

Earth-Abundant MoS2 and Cobalt Phosphate Dual Cocatalysts on 1D CdS Nanowires for Boosting Photocatalytic Hydrogen Production

Cocatalysts play a significant role in accelerating the catalytic reactions of semiconductor photocatalyst. In particular, a semiconductor assembled with dual cocatalysts, i.e., reduction and oxidation cocatalysts, can obviously enhance the photocatalytic performance because of the synergistic effect of fast consumption of photogenerated electrons and holes simultaneously. However, in most cases, noble metal cocatalysts are employed, which tremendously increases the cost of the photocatalysts and restricts their large-scale applications. Herein, on the platform of one-dimensional (1D) CdS nanowires, we have utilized the earth-abundant dual cocatalysts, MoS₂ and cobalt phosphate (Co-Pi), to construct the CdS@MoS₂@Co-Pi (CMC) core-shell hybrid photocatalysts. In this dual-cocatalyst system, Co-Pi is in a position to expedite the migration of holes from CdS, while MoS₂ acts as an electron transporter as well as active sites to accelerate the surface water reduction reaction. Taking the advantages of the dual-cocatalyst system, the prepared CMC hybrid shows an obvious enhancement of both the photoactivity and photostability toward hydrogen production compared with bare 1D CdS nanowires and binary hybrids (CdS@MoS₂ and CdS@Co-Pi). This work highlights the promising prospects for rational utilization of earth-abundant dual cocatalysts to design low-cost and efficient hybrids toward boosting photoredox catalysis.

Oxygen deficiency introduced to Z-scheme CdS/WO3-x nanomaterials with MoS2 as the cocatalyst towards enhancing visible-light-driven hydrogen evolution

An oxygen deficiency modified Z-scheme CdS/WO3-x nanohybrid with MoS2 as the cocatalyst was synthesized by a microwave hydrothermal method and was used for photocatalytic hydrogen production under visible light irradiation. Loadings of WO3-x and MoS2 as well as the synthesis time of the microwave-assisted hydrothermal process were optimized, and the physicochemical and optical properties of the as-prepared photocatalysts were characterized by various techniques. Results showed that the material with 30 wt% of WO3-x, 0.1 wt% of MoS2 and a preparation time of 120 minutes exhibited the most desirable morphology and structure for hydrogen production. The maximum hydrogen production of 2852.5 μmol g-1 h-1 was achieved, which was 5.5 times that of pure CdS (519.1 μmol g-1 h-1) and 1.5 times that of CdS/30 wt% WO3-x (1879.0 μmol g-1 h-1), and the external quantum efficiency (EQE) reached 10.0% at 420 nm. The improvement of photocatalytic performance could be attributed to the Z-scheme formed between CdS and WO3-x and MoS2 as an electron trap. It is worth mentioning that the size of the composite had a negative correlation with the H2 production rate.

Photoelectron directional transfer over a g-C3N4/CdS heterojunction modulated with WP for efficient photocatalytic hydrogen evolution

The separation and transfer of photoelectrons is a crucial factor in the process of photocatalysis.

Properties of monoclinic wolframite structure InWO4 for efficient and sustainable photocatalytic hydrogen evolution

This is the first report on the application of InWO₄ nanospheres in the field of photocatalysis.

Bi-component synergic effect in lily-like CdS/Cu7S4 QDs for dye degradation

CdS has attracted extensive attention in the photocatalytic degradation of wastewater due to its relatively narrow bandgap and various microstructures. Previous reports have focused on CdS coupled with other semiconductors to reduce the photocorrosion and improve the photocatalytic performance. Herein, a 3D hierarchical CdS/Cu₇S₄ nanostructure was synthesized by cation exchange using lily-like CdS as template. The heterojunction material completely inherits the special skeleton of the template material and optimizes the nano-scale morphology, and achieves the transformation from nanometer structure to quantum dots (QDs). The introduction of Cu ions not only tuned the band gap of the composites to promote the utilization of solar photons, more importantly, Fenton-like catalysis was combined into the degradation process. Compared with the experiments of organic dye degradation under different illumination conditions, the degradability of the CdS/Cu₇S₄ QDs is greatly superior to pure CdS. Therefore, the constructed CdS/Cu₇S₄ QDs further realized the optimization of degradation performance by the synergic effect of photo-catalysis and Fenton-like catalysis.

CdS has attracted extensive attention in the photocatalytic degradation of wastewater due to its relatively narrow bandgap and various microstructures.

CdS p–n heterojunction co-boosting with Co3O4 and Ni-MOF-74 for photocatalytic hydrogen evolution

A high-efficiency Ni-MOF-74/CdS/Co₃O₄ composite catalyst, the CdS co-boosting with Ni-MOF-74 and Co₃O₄, is successfully prepared.

Noble metal-free 0D–1D NiSx/CdS nanocomposites toward highly efficient photocatalytic contamination removal and hydrogen evolution under visible light

The heterostructures formed between 1D CdS nanorods and 0D NiS_xnanoclusters were prepared and showed high photocatalytic activity.