Plasmon Enhanced Deposition of Single Atom Catalysts

We developed a noble method to synthesize single atom nickel catalysts using the plasmon enhanced photo-deposition method. Single-atom catalysts (SACs) provide superior efficiency, selectivity, and tunability for catalysis. So far most of the synthesis methods of SACs required complex chemical steps, extreme conditions, or sophisticated instruments. SACs deposition under mild conditions using visible light can encourage their wide-scale applications. Plasmonic nanomaterials can efficiently absorb and concentrate light at the nanoscale to generate intense electromagnetic fields. The photoexcited electrons can undergo nonradiative decay, generating highly energetic electrons which can reduce metal cations adsorbed on the surface to deposit metal atoms on the surface. The reduction rate of metal cations can be easily controlled by varying light intensities and wavelengths to efficiently deposit single atoms. Here we deposited nickel single atoms on refractory plasmonic titanium nitride (TiN) nanomaterials which exhibit high-temperature stability, strong surface plasmon resonance, and can absorb a broad spectrum of solar light. We studied the Ni deposition on TiN nanoparticles by varying the light intensities, reaction time, and metal precursor concentration. SACs deposition is enhanced with the increase in light intensities (576 mW cm^-2). Both XPS data and DFT calculations suggested Ni single atoms favorably deposit on N-vacancies sites and then on N sites on the TiN surface.