In this contribution, a single pot approach was employed to synthesize nanoscale BiVO4/BiOX/Pd, where the halogen was varied over Cl, Br, and I. These materials were used to study the effect of the halide identity in the BiOX nanoplate component for its ability to modulate/maximize the photocatalytic properties of the materials. Once the nanomaterials were fully characterized via a suite of approaches, their reactivity for the degradation of rhodamine B, a model pollutant, was examined. All of the materials demonstrated high photocatalytic rates, reaching completion in <10 min in most cases. The results demonstrated that the BiVO4/BiOCl/Pd and BiVO4/BiOBr/Pd have significantly enhanced reactivity compared to the BiVO4/BiOI/Pd structures. Further studies using the BiVO4/BiOBr/Pd in the degradation of rhodamine B in natural water samples indicated that the materials retained their reactivity, demonstrating their potential use in environmental systems.

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Herein we report an ultrasonic-and photobased synthetic approach for the production of size-selective SrTiO 3 nanomaterials that are surface-decorated with Pd nanoparticle cocatalysts for application as photocatalysts for organic dye degradation. Control over the final nanoparticle size was achieved through selection of both reagent concentrations and stoichiometries, allowing for the ability to generate structures with sizes between 50 and 155 nm. Pd nanoparticles were subsequently photochemically deposited onto the surface of the oxide materials to serve as cocatalysts for enhanced reactivity. The materials were fully characterized and then examined for their photocatalytic reactivity, where their overall catalytic properties were controlled by three factors: (i) composition, (ii) size, and (iii) particle surface charge. These studies demonstrate important information that correlates synthetic conditions to final material properties, providing approaches to generate materials with optimal reactivity. Such effects could likely be translated to additional systems for applications beyond photocatalysis, such as energy harvesting, plasmonics, sensing, etc.

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Covalent organic frameworks (COFs) are promising candidates for heterogeneous photocatalytic reactions, though highly efficacious semiconductor–metal assemblies are often required to foster their photocatalytic performance. Herein, we report an efficient photocatalytic hybrid material that involves loading azine-based COF spheres onto Cu2O cubes and decorating them with palladium nanoparticles. The photocatalytic performance of the material was studied via the light-driven degradation of chlorinated biphenyls. The Cu2O-ACOF-1@Pd system demonstrated an outstanding performance over the bare Cu2O or ACOF-1, which can be attributed to the synergistic effect induced by the multicomponent tandem photocatalyst. It is shown that for monochlorinated biphenyls, the congener with a chlorine atom in the para position is more vulnerable to degradation than its meta and ortho counterparts because of electronic effects and being less sterically hindered. Moreover, the presence of a chlorine atom in the para position as an electron donor increases the conjugation between the phenyl rings, which in turn increases the driving force for planarity that facilitates the removal of the chlorine atom. This trend could be attributed to the reactivity of superoxide radicals toward the different congeners of monochlorinated biphenyls. The data revealed that nucleophilic substitution occurring at the para position is characterized by the lowest Gibbs free energy, while that occurring at the ortho position is characterized by the highest Gibbs free energy.