Haohao Huang

Photochemical preparation of Cd/CdS photocatalysts and their efficient photocatalytic hydrogen production under visible light irradiation

Metal Cd can serve as an analogue of cocatalysts loaded on CdS to separate electrons and holes to significantly enhance the efficiency of CdS photocatalytic hydrogen production. A series of Cd/CdS photocatalysts were synthesized at various molar ratios of CdSO4 and Na2S2O3·5H2O in the presence of simulated solar irradiation. Superior photocatalytic activities relative to that of pure CdS were observed on the Cd/CdS photocatalysts. When the optimal molar ratio R of Na2S2O3·5H2O to cadmium salt is 7, it results in a high average H2-production rate of 1753 μmol h−1. Possible mechanisms for both the formation and the enhanced photocatalytic activity of Cd/CdS were proposed on the basis of theoretical speculation and experimental observations. Most of all, this work highlights that (i) Cd/CdS leads to an improvement in the photocatalytic activity for H2 generation; and (ii) adding Na2S2O3·5H2O into the solution containing cadmium ions to prepare Cd/CdS can effectively remove cadmium ions.

Highly Efficient Photocatalytic Hydrogen Production of Flower-like Cadmium Sulfide Decorated by Histidine

Morphology-controlled synthesis of CdS can significantly enhance the efficiency of its photocatalytic hydrogen production. In this study, a novel three-dimensional (3D) flower-like CdS is synthesized via a facile template-free hydrothermal process using Cd(NO3)2•4H2O and thiourea as precursors and L-Histidine as a chelating agent. The morphology, crystal phase, and photoelectrochemical performance of the flower-like CdS and pure CdS nanocrystals are carefully investigated via various characterizations. Superior photocatalytic activity relative to that of pure CdS is observed on the flower-like CdS photocatalyst under visible light irradiation, which is nearly 13 times of pure CdS. On the basis of the results from SEM studies and our analysis, a growth mechanism of flower-like CdS is proposed by capturing the shape evolution. The imidazole ring of L-Histidine captures the Cd ions from the solution, and prevents the growth of the CdS nanoparticles. Furthermore, the photocatalytic contrast experiments illustrate that the as-synthesized flower-like CdS with L-Histidine is more stable than CdS without L-Histidine in the hydrogen generation.

Photodegradation of textile dye Rhodamine B over a novel biopolymer-metal complex wool-Pd/CdS photocatalysts under visible light irradiation.

A novel biopolymer-metal complex wool-Pd/CdS photocatalysts were prepared and exhibited high activity for photodegradation of Rh B under visible light irradiation. The wool-Pd could not only enhance the utilization rate of noble metal Pd but also significantly improve the activity of dye degradation. Wool-Pd was able to introduce Pd and PdS to effectively prohibit the recombination of photogenerated electrons and holes. The optimal weight percentage of wool-Pd in the photocatalyst was found to be 0.5wt%, which resulted in a good result of degradation of Rh B under visible light. It is obviously better in the catalyst efficiency than pure CdS. The photocatalysts were characterized by X-ray diffraction, diffuse reflectance UV-vis spectroscopy, energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopic (XPS) studies, transmission electron microscopy (TEM). In a word, the prepared novel biopolymer-metal complex wool-Pd/CdS photocatalysts not only improve the degradation efficiency of Rh B, but also has a good advantage of recycling and cost-effective. It will have a good application prospect. In addition, the possible degradation pathway of Rh B was proposed in this paper.

Photodegradation of Rhodamine B over a novel photocatalyst of feather keratin decorated CdS under visible light irradiation

A novel photocatalyst of feather keratin (FK)-decorated CdS was synthesized by a simple co-precipitation method. Scanning electron microscopy (SEM) showed that the particle sizes of FK/CdS nanocomposites were smaller than pure CdS. The coexistence of FK and CdS in the photocatalysts was further confirmed by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results of photocatalytic experiments demonstrated that the FK/CdS composites exhibit significantly enhanced photocatalytic activity for the photocatalytic degradation of RhB compared with pure CdS under visible light irradiation. The enhanced photocatalytic activity of the FK/CdS composites can be attributed to the similar affinity between FK and RhB, which can effectively separate the photogenerated electron–hole pairs. This method not only improves the photocatalytic activity of CdS, but also reduces the environmental pollution of waste feathers. In addition, the possible degradation mechanism of RhB is proposed.

Preparation of a novel acid doped polyaniline adsorbent for removal of anionic pollutant from wastewater

Polyaniline (PANI) was one of the most extensively studied adsorbents due to its low cost and good environmental stability. The objective of the current study was to improve the selective capabilities of PANI for anionic dyes. We found that the acid doped PANI prepared with hydrochloric acid and p-toluenesulfonic acid (PTSA) could selectively adsorb anionic dyes. It exhibited very good selectivity for OG dye, the mechanism was proposed based on the chemical interaction of PANI with the sulfonate group of the dyes. The effects of solution pH, initial dye concentration, and different HCl/PTSA mole ratios on the adsorption capacity of OG have been investigated. Kinetic simulations indicated that the adsorption process could be well represented by pseudo-second-order kinetic plots. The isothermal adsorption curve fitting also showed that the adsorption process could be well described by the Langmuir isothermal equation. The results showed that acid doped PANI could be employed as a promising adsorbent for anion removal from dye wastewater.