In situ growing of CoO nanoparticles on g-C3N4 composites with highly improved photocatalytic activity for hydrogen evolution

Heterojunction formation between AgNbO3 and Co3O4 for full solar light utilization with improved charge-carrier separation

In the present study, the charge-carrier recombination of visible light active perovskite silver niobate (AgNbO₃) was reduced by forming heterojunction with Co₃O₄ through simple impregnation and calcination route. The loading percentage of Co₃O₄ was varied as 2, 5, and 10 wt.%. The XRD study revealed reduced interlayer spacing in the composite due to the replacement of the bigger Ag⁺ ions by the smaller Co²⁺ and Co³⁺ ions of Co₃O₄. It was observed that the light harvesting efficiency of the materials was increased with increased loading of Co₃O₄. The TEM and XPS analysis confirmed the presence of Ag nanoparticles over the perovskite in the composite. The electrochemical analysis revealed enhanced charge-carrier number density and increased charge-carrier lifetime in the composite as a result of the presence of both silver and cobalt ions in the lattice. Further this enhanced charge-carrier separation of the composites was established through photocatalysis of Bisphenol-A under both solar and LED light. Charge-trapping study indicated *O₂^- and *OH as the major radicals involved and Z-scheme as the predominant charge transfer pathway for generation of these reactive oxygen species.

Effects of various alcohol sacrificial agents on hydrogen evolution based on CoS2@SCN nanomaterials and its mechanism

Visible light induced photocatalysis converted solar energy to chemical energy in the form of hydrogen. g-C₃N₄ modified by thermal oxidation etching, doped S, and nonprecious metal cocatalyst CoS₂ (CoS₂@SCN) were used for photocatalytic hydrogen production. And then the charge transfer behavior and mechanism of various alcohol sacrificial agents on hydrogen evolution was analyzed by optical characterization, impedance analysis, Mott-Schottky, and photocurrent tests. The relationship between the structure and catalytic performance was also explored using characterization methods. The results showed that CoS₂ significantly improved the light absorption of g-C₃N₄, and carrier migration and separation. And when the sacrificial agent was triethanolamine, the nanocomposite CoS₂@SCN exhibited best catalytic performance with the highest hydrogen activity of 223.6 μmol g^-1 h^-1, the minimum volume in-phase charge transfer resistance with 55.19 Ω and the maximum photocurrent and photocurrent density with 5.5 μA cm^-2 and 0.63 mA cm^-2. The more negatively charged surface of organic alcohols were, the easier they were to react with holes, thus enhanced charge transfer and hydrogen production efficiency. This report provides guidance for the selection of hydrogen producing sacrificial agents and preparation of highly charge-efficient catalysts. And it also provides a theoretical basis for hydrogen production from wastewater and environmental remediation.

Electrospinning Preparation of GaN:ZnO Solid Solution Nanorods with Visible-Light-Driven Photocatalytic Activity toward H2 Production

The development of a facile method for the synthesis of GaN:ZnO solid solution, an attractive material with a wurtzite-type structure, is vital to enhance its photocatalytic activity toward H2 evolution. Herein, GaN:ZnO solid solution nanorods with diameters of around 180 nm were fabricated by combining the electro-spun method with a sequentially calcinating process. Photocatalytic water-splitting activities of the as-obtained samples loaded with Rh2−yCryO3 co-catalyst were estimated by H2 evolution under visible-light irradiation. The as-prepared GaN:ZnO nanorods at a nitridation temperature of 850 °C showed the optimal performance. Careful characterization of the GaN:ZnO solid solution nanorods indicated that the nitridation temperature is an important parameter affecting the photocatalytic performance, which is related to the specific surface area and the absorbable visible-light wavelength range. Finally, the mechanism of the GaN:ZnO solid solution nanorods was also investigated. The proposed synthesis strategy paves a new way to realize excellent activity and recyclability of GaN:ZnO solid solution nanorod photocatalysts for hydrogen generation.

Enhanced visible light photocatalytic water-splitting activity over LaVO4/g-C3N4 with oxygen defects

The photocatalytic water-splitting activity is enhanced by the LaVO4/g-C3N4 composite with oxygen defects.

An experimental study on the Co–C3N4/BiPO4 composite for efficient photocatalytic water splitting

The photocatalytic water-splitting activity is enhanced by the Co–C₃N₄/BiPO₄ photocatalyst without the use of a noble metal.