Seeded Growth of Metal Nitrides on Noble-Metal Nanoparticles To Form Complex Nanoscale Heterostructures

Colloidal heterostructured nanoparticles that integrate multiple materials through direct solid–solid interfaces are desirable across a wide range of applications. However, chemical, structural, interfacial, and synthetic considerations have limited the scope of materials that can be incorporated into such hybrid constructs. Metal nitrides are appealing components of heterostructured nanoparticles because of their unique and diverse electronic, photonic, and catalytic properties, but they can be challenging to synthesize. Here, we demonstrate that the model metal nitride systems Cu3N and Cu3PdN can be grown in solution on various noble-metal seed particles to form a library of heterostructured metal–metal nitride nanoparticles. The types of nanoscale heterostructures that form depend on both the morphology of the noble-metal seed particle and the material being deposited. The pathway by which Cu3PdN grows on Pt nanocube seeds involves initial nonselective deposition of Cu, followed by localized deposition of Pd at the corners along with concomitant incorporation of nitrogen and crystallization of Cu3PdN. Preferential Pd deposition at seed particle corners therefore drives regioselectivity during the growth of Cu3PdN, leading to the formation of Pt–Cu3PdN heterostructured nanoparticles. For seed particles that are not highly faceted, as well as Cu3N, localized deposition is not observed, and different types of core–shell and alloy nanoparticles form. Cu3PdN also deposits selectively on the exposed corners of the cube-shaped Pt domains of Pt–Fe3O4 hybrid nanoparticles, forming complex Fe3O4–Pt–Cu3PdN heterotrimers. These observations provide useful insights for incorporating metal nitrides into nanoscale heterostructures using seeded growth processes.