Homogeneous doping can boost solar-to-hydrogen conversion and therefore attracts great attention. Although a great deal of effort has been made to explore the doping–photoreactivity relationship, the doping mechanisms, especially from the perspective of crystal facets, are seldom explored. In this study, a general homogeneous carbon doping strategy is established and then serves as the doping model for a mechanistic investigation, as encouraged by its versatility in enabling homogeneous incorporation of carbon and improving solar-to-hydrogen conversion for typical oxides including TiO₂, ZnO, and BiOCl. Using well-defined BiOCl nanosheets of high {001} or {010} facet exposure, we clarify the homogeneous carbon doping mechanism at the level of crystal facets for the first time. This mechanism involves the initial facet-dependent adsorption of the dopant precursor, regulated by the surface atomic structures, and the subsequent facet-dependent diffusion of carbon dopants associated with the facet-related arrangements of bulk atoms. This results in facet-dependent carbon doping behavior and a dopant-concentration-dependent solar-to-hydrogen conversion property of BiOCl nanosheets. These mechanistic insights also suggest that the implantation of the dopant precursor in the shallow lattice of host nanocrystal is vital for the effective homogeneous doping. This new doping model is different from the conventional counterpart based on the organic ligands or gas molecules adsorption onto the surface of host nanocrystals, where surface doping usually occurs.

Noble metal nanoparticles (NPs) are often used as electron scavengers in conventional semiconductor photocatalysis to suppress electron–hole (e⁻–h⁺) recombination and promote interfacial charge transfer, and thus enhance photocatalytic activity of semiconductors. In this contribution, it is demonstrated that noble metal NPs such as Ag NPs function as visible-light harvesting and electron-generating centers during the daylight photocatalysis of AgBr@Ag. Novel Ag plasmonic photocatalysis could cooperate with the conventional AgBr semiconductor photocatalysis to enhance the overall daylight activity of AgBr@Ag greatly because of an interesting synergistic effect. After a systematic investigation of the daylight photocatalysis mechanism of AgBr@Ag, the synergistic effect was attributed to surface plasmon resonance induced local electric field enhancement on Ag, which can accelerate the generation of e⁻–h⁺ pairs in AgBr, so that more electrons are produced in the conduction band of AgBr under daylight irradiation. This study provides new insight into the photocatalytic mechanism of noble metal/semiconductor systems as well as the design and fabrication of novel plasmonic photocatalysts.

We report on a rapid microwave-assisted nonaqueous synthesis and the growth mechanism of AgCl/Ag with controlled size and shape. By rationally varying the reaction temperature and the microwave irradiation time, we achieved the transformation of nanocubes to rounded triangular pyramids by a combined process of “oriented attachment” and Ostwald ripening. The surface plasmon resonance (SPR) properties of the as-prepared AgCl/Ag have been found to be somewhat dependent on the size, morphology, and composition. The as-prepared AgCl/Ag exhibits high photocatalytic activity and good reusability for decomposing organic pollutants (such as methyl orange (MO), rhodamine B (RhB), and pentachlorophenol (PCP)) under indoor artificial daylight illumination (ca. 1 mW cm⁻²). The AgCl/Ag has also been found to display a superior ability to harvest diffuse indoor daylight (ca. 5 mW cm⁻²), and could complete the degradation of 10 mg L⁻¹ MO within 15 min. Experiments involving the trapping of active species have shown that the photocatalytic degradation of organic pollutants in the AgCl/Ag system may proceed through direct hole transfer. This study has revealed that plasmonic daylight photocatalysis may open a new frontier for indoor pollutant control around the clock under fluorescent lamp illumination.

Platinum nanostructured networks (PNNs) can be synthesized through the chemical reduction of H₂PtCl₆ by benzyl alcohol under microwave irradiation without the introduction of any surfactants, templates, or seeds. The synthesis route utilizes benzyl alcohol as both the reductant and the structure-directing agent, and thus, the process is particularly simple and highly repeatable. The formation of the PNN structure was ascribed to the collision-induced fusion of Pt nanocrystals owing to the cooperative functions of microwave irradiation and benzyl alcohol. Compared with a commercial Pt/C catalyst, the as-prepared PNNs possessed superior electrochemical activity and stability on the oxidation of methanol because of the unique 3D nanostructured networks and abundant defects formed during the assembly process. This study may provide a facile microwave-induced approach for the synthesis of other 3D nanostructured noble metals or their alloys.

Hollow ZnV₂O₄ microspheres with a clewlike feature were synthesized by reacting zinc nitrate hexahydrate and ammonium metavanadate in benzyl alcohol at 180 °C for the first time. GC–MS analysis revealed that the organic reactions that occurred in this study were rather different from those in benzyl alcohol based nonaqueous sol–gel systems with metal alkoxides, acetylacetonates, and acetates as the precursors. Time-dependent experiments revealed that the growth mechanism of the clewlike ZnV₂O₄ hollow microspheres might involve a unique multistep pathway. First, the generation and self-assembly of ZnO nanosheets into metastable hierarchical microspheres as well as the generation of VO₂ particles took place quickly. Then, clewlike ZnV₂O₄ hollow spheres were gradually produced by means of a repeating reaction–dissolution (RD) process. In this process, the outside ZnO nanosheets of hierarchical microspheres would first react with neighboring vanadium ions and benzyl alcohol and also serve as the secondary nucleation sites for the subsequently formed ZnV₂O₄ nanocrystals. With the reaction proceeding, the interior ZnO would dissolve and then spontaneously diffuse outwards to nucleate as ZnO nanocrystals on the preformed ZnV₂O₄ nanowires. These renascent ZnO nanocrystals would further react with VO₂ and benzyl alcohol, ultimately resulting in the final formation of a hollow spatial structure. The lithium storage ability of clewlike ZnV₂O₄ hollow microspheres was studied. When cycled at 50 mA g⁻¹ in the voltage range of 0.01–3 V, this peculiarly structured ZnV₂O₄ electrode delivered an initial reversible capacity of 548 mAh g⁻¹ and exhibited almost stable cycling performance to maintain a capacity of 524 mAh g⁻¹ over 50 cycles. This attractive lithium storage performance suggests that the resulting clewlike ZnV₂O₄ hollow spheres are promising for lithium-ion batteries.

A general nonaqueous route for the synthesis of phase-pure transition-metal niobate (InNbO₄, MnNb₂O₆, and YNbO₄) nanocrystals was developed based on the one-pot solvothermal reaction of niobium chloride and the corresponding transition-metal acetylacetonates in benzyl alcohol at 200 °C. All samples were carefully characterized by XRD, TEM, HRTEM, and energy-dispersive X-ray (EDX) analysis. The crystallization mechanism of these niobate nanocrystals points to a two-step pathway. First, metal hydroxide crystals and amorphous niobium oxide are formed. Second, metal niobate nanocrystals are generated from the intermediates by a dissolution–recrystallization mechanism. The reaction mechanisms, that is, the processes responsible for the oxygen supply for oxide formation, were found to be rather complex and involve niobium-mediated ether elimination as the main pathway, accompanied by solvolysis of the acetylacetonate ligands and benzylation reactions.