•Mesoporous silica particles were first synthesized by using THEEDA as catalyst.•The particles with the size about 30 nm present stable colloidal suspensions.•Thiol functional groups were modified into the silica particles.•Examined the influence of adjusting TEOS/MPTMS on the structure and morphology.•The modification particles could effectively remove heavy metal ions Au3+ and Hg2+.Colloidal suspensions of monodispersed nanoporous silica particles were first successfully synthesized by using small organic amine (N,N,N′,N′-Tetrakis(2-hydroxyethyl)ethylenediamine) as basic catalyst; and then, the mercaptopropyl functionalized counterpart was also fabricated by co-condensation of mercaptopropyl silane and tetraethyl orthosilicate in a similar way. These nanoporous silica particles were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), nitrogen adsorption-desorption and X-ray diffraction. Experimental results indicated that all the spherical nanoporus silica particles are uniform (with the size of about 30–40 nm) and possessed large specific surface area (about 500 m2/g), large pore volume (>1.6 cm3g−1) and narrow pore sizes distribution (<3 nm). Furthermore, the mercaptopropyl functionalized products served as adsorbent to efficiently remove Hg2+ and Au3+ ions in water.

•Ni nanoparticles with high crystallization are prepared by chemical reduction and then loaded on CdS surface by photo-reduction.•Non-noble metal Ni nanocrystallines act as co-catalyst for photocatalytic water splitting-hydrogen evolution.•Ni/CdS exhibits high activity (25.848 mmol h−1·g−1 (QE = 26.8%, λ = 420 nm)) and perfect stability.Ni nanoparticles were prepared via chemical reduction of aqueous NiCl2·6H2O by N2H4·H2O, and loaded on the surface of CdS by photo-induced electrons as water splitting reaction was occurring. Resultant CdS modified with Ni nanoparticles (denoted as Ni/CdS) was characterized by transmission electron microscopy, X-ray diffraction, UV–vis diffuse reflectance spectrometry, and photoluminescence spectrometry, and its photocatalytic performance for water splitting under visible light irradiation producing hydrogen was evaluated with a 300 W Xe lamp as the light source (λ ≥ 420 nm). It was found that as-obtained Ni nanoparticles with an average size of about 10 nm have face centered cubic structure, and they are preferentially deposited on the (100), (002), and (101) crystal planes of CdS nanorods to afford Ni/CdS photocatalyst. Besides, as-prepared Ni/CdS photocatalyst has a surface area of 28.8 m2/g (determined by BET method), higher than that of CdS nanorods, which indicates that Ni nanoparticles is beneficial to increasing the surface area of CdS nanorods. Moreover, as-prepared Ni/CdS photocatalyst shows absorption traits in the visible light region, and its photoluminescence peak intensity is lower than that of CdS, which means that Ni nanoparticles function as the trappers of photo-generated electrons to quench the photoluminescence of CdS. More importantly, although pristine CdS exhibits no activity for hydrogen production from water splitting under visible light irradiation, Ni/CdS photocatalyst with a Ni content of 4% (mass fraction) provides a hydrogen production rate of 25.848 mmol/(h g) (QE = 26.8%, λ = 420 nm) from water splitting of (NH4)2SO3 aqueous solution under the same testing condition and it retains a high stability and activity even after 20 h of water splitting. This demonstrates that Ni/CdS could be a promising candidate photocatalyst for visible light water splitting yielding hydrogen.

In this paper, nano-rod CdS was prepared by using a solvothermal method adopting thiourea as sulfur source. The micro-morphology and structure of the as-prepared CdS were investigated by using XRD, HRTEM, and ED, based on which it is suggested that the nano-rod CdS may have a preferential orientation growth along c-axis. Experiments of water splitting were performed with a 300 W Xe light as resources (λ > 420 nm). The preparation conditions of solvothermal reaction were systematically studied. The CdS synthesized at 160 °C had a high photo-activity with a hydrogen evolution rate at 34 mmol/h/gCat. Moreover, the as-prepared CdS possessed a large BET surface area of 36.7 m2/g and pore volume of 0.09 cm3/g. Therefore, the high activity might be due to its high crystallinity and large surface area.

In this paper, the surface states of Pt/TiO2 thin film were tested in air, H2 and N2 flows. Pt/TiO2 was prepared by means of photoreduction of PtCl62- on anatase nano-TiO2 powders and was coated on the microscopy glass using powder–sol technique. Powder conductivity method was applied in the analysis of surface states. The experimental results show that a new surface state was formed in air flow; which was 0.43 eV lower than the conduction band edge of TiO2. In N2 flow, three surface states, with the energy levels of 0.42, 0.62 and 0.90 eV, respectively, were detected. Compared with that tested in airflow, 0.42 and 0.62 eV could be attributed to Pt and floating bond of TiO2 respectively, while 0.90 eV might have resulted from the Ti3+ formed at high temperature in N2 flow. The conductivity of the sample tested in H2 flow increased significantly and was almost unchanged with temperature, which could be interpreted by the dissociative adsorption of H2 on Pt.

Nano-TiO2 powder was prepared by sol–gel method with modified precursor, tetrabutyl titanate (TBT), and photocatalytic oxidation was applied in removal of organics in the powder. The microstructure of as-prepared nano-TiO2 was determined using UV–vis, TEM, XRD and BET. The results indicated that the nano-TiO2, with grain size of 3.8 nm and specific surface area of 359.1 m2/g, was composed of anatase alone, and that it exhibited significant blue-shift in its UV–vis spectrum. The decomposition of organics in the sample was systematically investigated using FT-IR and TG-DTA. According to the testing results, we could conclude that organics in the samples were completely eliminated by means of photocatalytic oxidation. With photocatalytic decoloration of active brilliant red X-3B in aqueous solution as model reaction, the photocatalytic activity of as-prepared nano-TiO2 was investigated and was compared with that of the samples experiencing heat treatment and Degussa P-25 as well. The experimental results indicated that the photoactivity of as-prepared nano-TiO2 is much higher than that of the samples experiencing heat treatment.

In this paper, the surface states of Pt/TiO2 thin film were tested in air, H2 and N2 flows. Pt/TiO2 was prepared by means of photoreduction of PtCl62- on anatase nano-TiO2 powders and was coated on the microscopy glass using powder–sol technique. Powder conductivity method was applied in the analysis of surface states. The experimental results show that a new surface state was formed in air flow; which was 0.43 eV lower than the conduction band edge of TiO2. In N2 flow, three surface states, with the energy levels of 0.42, 0.62 and 0.90 eV, respectively, were detected. Compared with that tested in airflow, 0.42 and 0.62 eV could be attributed to Pt and floating bond of TiO2 respectively, while 0.90 eV might have resulted from the Ti3+ formed at high temperature in N2 flow. The conductivity of the sample tested in H2 flow increased significantly and was almost unchanged with temperature, which could be interpreted by the dissociative adsorption of H2 on Pt.