The study of nanocrystal self‐assembly into superlattices or superstructures is of great significance in nanoscience. Carbon nitride quantum dots (CNQDs), being a promising new group of nanomaterials, however, have hardly been explored in their self‐organizing behavior. Here we report of a unique irradiation‐triggered self‐assembly and recrystallization phenomenon of crystalline CNQDs (c‐CNQDs) terminated by abundant oxygen‐containing groups. Unlike the conventional self‐assembly of nanocrystals into ordered superstructures, the photoinduced self‐assembly of c‐CNQDs resembles a “click reaction” process of macromolecules, in which the activated ‐OH and ‐NH2 functional groups along the perimeters initiate cross‐linking of adjacent QDs through a photocatalytic effect. Our findings unveil fundamental physiochemical features of CNQDs and open up new possibilities of manipulating carbon nitride nanomaterials via controlled assembly. Prospects for potential applications are discussed as well.

A novel dot-like Cu2O-loaded TiO2/reduced graphene oxide (rGO) nanoheterojunction was synthesized via UV light reduction for the first time. Cu2O with size of ca. 5 nm was deposited on rGO sheet and TiO2 nanosheets. The products were characterized by infrared spectroscopy, Raman spectrum, UV–Vis diffuse reflectance spectra, XPS techniques, photoluminescence spectra. The results demonstrated that Cu2O and rGO enhanced the absorption for solar light, separation efficiency of electron–hole pairs, charge shuttle and transfer, and eventually improved photoelectrochemical and photocatalytic performance for contaminants degradation. The reaction time and anion precursor could affect the final copper-containing phase. As extending UV irradiation time, Cu2+ was be first reduced to Cu2O and then transformed to metal Cu. In comparison with CH3COO− (copper acetate), NO3 − (copper nitrate) and Cl− (copper chloride), SO4 2− (copper sulfate) was the optimum for synthesizing pure Cu2O phase.Electronic supplementary materialThe online version of this article (doi:10.1007/s10853-017-0911-2) contains supplementary material, which is available to authorized users.

Cadmium chalcogenides–metal hybrid nanostructures play an important role in a wide range of applications and are key components in photocatalysis. Hence, great efforts have been devoted to the exploration of a variety of metal components, each offering different functionalities. Silver is a vital catalyst used in the production of major industrial chemicals, found in virtually every electronic device, widely exploited as an antibacterial agent, used in fuel cells, and has been extensively investigated for CO2 reduction. Yet, silver nanoparticles were not utilized in conjunction with cadmium chalcogenide colloidal nanostructures due to the tendency of Ag+ to undergo cation exchange. We present here a new strategy that opens up a pathway for avoiding cation exchange and obtaining metallic silver tipping on cadmium chalcogenide nanorods. The formation of Ag trioctylphosphine complex, as an intermediate in the course of Ag deposition on nanorods, was identified to be a critical step, which prevents undesirable cation exchange. Metallic Ag was confirmed by several advanced techniques and its growth location on the tip of nanorods was carefully studied. Moderate control over the crystalline Ag tip size was demonstrated in the range of 1.5–5.4 nm.

High exchange-coupled Nd2Fe14B/Fe3B nanocomposites were synthesized by an integrative procedure of thermal decomposition and reductive annealing processes. The molar ratio of the resulting products of Nd/Fe/B can be tuned by adjusting the raw material proportion. The as-prepared nanocomposites exhibited an exchanged coupled effect with a large coercivity of 11 100 Gs, enhanced remanence Mr of 42.0 emu g(-1), and Mr/M3T of 0.59.

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