Development of new nanothermometry platforms for plasmonic catalysis reactions

Author(s)

Tamires Maira Oliveira

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2022-11-11

Examining board members

Paulo Cesar de Sousa Filho; Fernando Aparecido Sígoli; Lucas Carvalho Veloso Rodrigues

• Advisor: Paulo Cesar de Sousa Filho

Abstract

Plasmonic metal nanoparticles (NPs) show unique characteristics for emerging applications in optical sensing and catalysis, which stimulates fundamental and applied research in this field. In turn, accurate description of mechanisms of reaction mediated by irradiated metal NPs is still limited by the difficult determination of local temperatures to ascribe thermal contributions. Combining optical nanothermometers based on lanthanide and plasmonic NPs is therefore a promising approach to afford insights into the underlying mechanisms in plasmonic photocatalysis. In this sense, we proposed a rare-earth vanadate-based platform decorated with gold nanoparticles or nanorods (REVO4-AuNPs/AuNRs), in which the REVO4 phase shows a thermometric response to address temperature fluctuations around the metal NPs during photocatalytic assays. Comparing bare (Y,Yb,Tm,Er)VO4 particles and AuNRs- functionalized systems revealed significant changes in the profile of Er 3+ 2H11/2 ?4I15/2 , 4S3/2 ?4I15/2 emissions at ?exc = 808 nm, where the high energy component showed higher intensity due to the local temperature increase caused by the AuNRs. This effect is suppressed if this sample is dispersed in water, thus indicating a higher degree of energy dissipation. Intensity vs. power profiles also showed the effects of AuNRs on upconversion mechanisms, with a decrease in the number of photons required for Er3+ emissions when AuNRs are grafted on vanadate particles. This was also confirmed by in situ luminescence measurements monitoring progressive deposition of AuNRs over (Y,Yb,Tm,Er)VO4 particles. Catalysis assays based on the model plasmonic reaction of 4-nitrophenol reduction to 4-aminophenol by NaBH4 under ?exc=740 nm demonstrated the positive interaction between the (Y,Yb,Tm,Er)VO4 catalytic support and AuNRs. Hence, this work demonstrate the combination of luminescent NPs with AuNRs, which will potentially provide information about the temperature fluctuations surrounding the AuNRs and the effect of REVO4 as a catalytic support in plasmonic catalysis (AU)

• FAPESP's process: 19/21896-9 - Development of new nanothermometry platforms for plasmonic catalysis reactions
• Grantee: Tamires Maira Oliveira
• Support Opportunities: Scholarships in Brazil - Master