In situ FTIR spectroscopic studies of reaction mechanisms for photocatalytic reduction of CO2 by CuPt/TiO2 nanotube composites

  • 張 旭蕙

Student thesis: Master's Thesis

Abstract

Rising atmospheric levels of CO2 has given rise to great concerns in climate change Photocatalytic reduction of CO2 is a promising pathway utilizing the abundant solar energy to convert CO2 to low-carbon fuels or chemicals CO2 adsorption is an initial and key step for the multi-electron electron transfer photocatalytic process It is essential to have a better understanding of the photocatalyst surface chemistry In this study the one-dimensional titania nanotube (TiNT) and metal-loaded TiNT photocatalysts were studied by in situ infrared spectroscopy TiNT was prepared by the hydrothermal method in alkaline solution In addition TiNT was further modified with metal co-catalysts Copper and platinum nanoparticles were loaded on the TiNT with the chemical photodeposition method The SEM and TEM images show the tubular structure of TiNT with the length of 100 nm and outer/inner opening diameters of 9-15/3-5 nm and the metal nanoparticles were uniformly dispersed on TiNT The high surface area (120 m2/g) of the TiNT was measured by N2 adsorption-desorption isotherm Surface defects including Ti3+ and oxygen vacancies of the photocatalyst were measured by XPS and Raman spectroscopy The FTIR spectra and CO2-TPD data suggest that the TiNT have a strong affinity to the CO2 molecules compared to the pristine TiO2 By in situ FTIR studies for CO2 adsorption a number of peaks related to the adsorbed carbonate species (1200-1800 cm-1) are found including bidentate carbonate (b-CO32-) monodentate carbonate (m-CO32-) bicarbonate (HCO3-) and carboxyl species (CO2-) For the Cu/TiNT the defect-rich (Ti3+/oxygen vacancies) surface may provide active sites to promote the CO2 adsorption ability Note that the adsorbed carboxylate species (CO2-) formation are observed on the TiNT The observations show that the adsorption capacity and formation of carboxylate species may be adsorbed on the surface-active sites To enhance the photocatalytic activity more research should focus on the modification of detect-rich materials to promote CO2 adsorption and electron transfer
Date of Award2018 Sep 1
Original languageEnglish
SupervisorHong-Paul Wang (Supervisor)

Cite this

In situ FTIR spectroscopic studies of reaction mechanisms for photocatalytic reduction of CO2 by CuPt/TiO2 nanotube composites
旭蕙, 張. (Author). 2018 Sep 1

Student thesis: Master's Thesis