Rapid Construction of Double Crystalline Prussian Blue Analogue Hetero-Superstructure

Interfacial engineering of Co(OH)2@CN composites: A study of p-n heterojunctions with enhanced xylose/xylan photoreforming and CO2 reduction performance

The construction of p-n heterojunction is considered a prominent method for promoting efficient separation/migration of photoinduced carriers, thereby enhancing photocatalytic performance. Herein, a series of nanoflower spherical Co(OH)2@CN-x p-n heterojunction photocatalysts were fabricated using a simplified one-step hydrothermal strategy. Notably, Co(OH)2@CN-2 exhibited optimal performance, showcasing a carbon monoxide (CO) evolution rate of 46.2 μmol g-1 h-1 and a xylonic acid yield of 69.9 %. These values are 14.7/3.7 and 2.8/2.4 times higher than those of pristine CN and Co(OH)2, respectively. Additionally, Co(OH)2@CN-2 demonstrated excellent recyclability and chemical stability. Comparative experiments, coupled with 13CO2-labelling testing, confirmed the carbon sources of the obtained CO (72.3 % from CO2 reduction and 27.7 % from xylose oxidation). The charge transfer mechanism in Co(OH)2@CN-x p-n heterojunctions was systematically elucidated using in-situ X-ray photoelectron spectroscopy (in-situ XPS) and density functional theory (DFT) calculations. This work presents a practical approach for constructing p-n heterojunction photocatalysts to enhance photocatalytic biomass oxidation coupled with CO2 reduction.

Self-Sustained-Release Strategy Realizes Colloid Oriented Assembly to Fabricate Prussian Blue with Hierarchical Structure

The controlled self-assembly of nanomaterials has been a great challenge in nanosynthesis, especially for hierarchical architectures with high complexity. Particularly, the structural design of Prussian blue (PB) series materials with robustness and fast nucleation is even more difficult. Herein, a self-sustained-release strategy based on the slow release of metal ions from coordination ions is proposed to guide the assembly of PB crystals. The key to this strategy is the slow release by ligand, which can create ultra-low concentrations of metal ions so as to provide the possibility to realize the surface charge manipulation of PB primary colloids. By adding electrolyte or changing the polarity of the solution, the surface charge regulation of PB colloid is realized, and the PB hierarchical structures with branch fractal structure (PB-BS), octahedral fractal structure, and spherical fractal structure are effectively constructed. This work not only achieves the designability of the PB structure, but also synchronizes the functionalization during the PB assembly growth process by in situ encapsulation of the effective catalytic active component L-Ascorbic acid. As a result, the assembled PB-BS exhibits greatly enhanced catalytic activity and selectivity in styrene oxidation with the selectivity of oxidized styrene increasing from 35.6% (PB) to 80.5% (PB-BS).

Regioselective super-assembly of Prussian blue analogue

The construction of high-asymmetrical structures demonstrates significant potential in improving the functionality and distinctness of nanomaterials, but remains a considerable challenge. Herein, we develop a one-pot method to fabricate regioselective super-assembly of Prussian blue analogue (PBA) -- a PBA anisotropic structure (PBA-AS) decorated with epitaxial modules--using a step-by-step epitaxial growth on a rapidly self-assembled cubic substrate guided by thiocyanuric acid (TCA) molecules. The epitaxial growth units manifest as diverse geometric shapes, which are predominantly concentrated on the {100}, {111}, or {100}+{111} crystal plane of the cubic substrate. The crystal plane and morphology of epitaxial module can be regulated by changing the TCA concentration and reaction temperature, enabling a high level of controllability over specific assembly sites and structures. To illustrate the advantage of the asymmetrical structure, phosphated PBA-AS demonstrates improved performance in the oxygen evolution reaction compared to simple phosphated PBA nanocube. This method offers valuable insights for designing asymmetrical nanomaterials with intricate architectures and versatile functionalities.