Opportunity
The development of heterostructured nanomaterials has garnered significant attention due to their tunable morphologies, interfaces, and spatial arrangements, which enable superior physicochemical properties. However, precise control over the phase structure of noble metal-semiconductor heterostructures remains a major challenge. Conventional crystalline noble metals, while catalytically active, often lack the rich non-coordinated sites and dangling bonds found in amorphous structures, which are critical for enhanced catalytic performance. Additionally, the instability of amorphous noble metal nanostructures during semiconductor growth often leads to their transformation into thermodynamically stable crystalline phases, limiting their practical applications. This patent addresses these limitations by providing a robust and universal method to synthesize stable amorphous noble metal-crystalline semiconductor/metal heterophase nanoparticles, which exhibit exceptional catalytic activity and stability for applications such as electrocatalysis and photocatalysis.
Technology
This patent introduces a novel wet-chemical synthesis method to create amorphous noble metal-crystalline semiconductor/metal heterophase nanoparticles. The key innovation lies in the precise control of the amorphous-crystalline interface, enabling the formation of either core-shell structures (amorphous noble metal core with crystalline semiconductor/metal shell) or Janus structures (adjacent amorphous and crystalline regions). The method involves using pre-synthesized amorphous noble metal nanoparticles (e.g., amorphous Pd) as seeds, followed by controlled growth of crystalline semiconductors (e.g., CdS, Ni₃S₂, Cu₂₋ₓS) or metals (e.g., Au, Ag) on these seeds under mild conditions. The amorphous phase is preserved by optimizing reaction parameters such as temperature, injection rate, and precursor ratios. The resulting heterostructures exhibit synergistic effects, such as efficient separation of photoinduced electrons and holes, enhanced light absorption, and superior catalytic activity. For example, amorphous Pd-crystalline CdS (aPd-cCdS) heterostructures demonstrate remarkable performance in photocatalytic C-N coupling reactions, simultaneously producing hydrogen and high-value imines with high selectivity and stability.
Advantages
- Enhanced Catalytic Activity: The amorphous noble metal regions provide abundant active sites, while the crystalline semiconductor/metal regions facilitate efficient charge separation and light absorption.
- High Stability: The heterostructures maintain their amorphous-crystalline interface under reaction conditions, avoiding phase transformation.
- Versatile Synthesis: The method is applicable to various noble metals (Pd, Au, Ag) and semiconductors/metals (CdS, Ni₃S₂, Cu₂₋ₓS), enabling tailored designs for specific applications.
- Synergistic Effects: The combination of amorphous and crystalline phases improves charge transfer and reaction kinetics.
- Scalability: The wet-chemical approach is suitable for large-scale production.
Applications
- Photocatalysis: Efficient production of hydrogen and high-value organic compounds (e.g., imines) under mild conditions.
- Electrocatalysis: Enhanced performance in reactions such as hydrogen evolution (HER) and oxygen reduction (ORR).
- Environmental Remediation: Degradation of pollutants using solar energy.
- Chemical Synthesis: Selective C-N coupling reactions for pharmaceutical and agrochemical intermediates.
- Energy Storage: Potential use in fuel cells and batteries due to improved catalytic efficiency.
