Photo-mediated co-loading of highly dispersed MnOx-Pt on g-C3N4 boosts the ambient catalytic oxidation of formaldehyde

Abstract

Exploration of effective metal/support combinations and new fabrication approaches is attractive in the catalytic oxidation of HCHO. In this study, we proposed graphitic carbon nitride (g-C₃N₄) as a non-metal oxide based support to co-load Pt and MnO_x through room-temperature photodeposition and in turn applied for HCHO oxidation. Here, Pt was the active component, while MnO_x was the cocatalyst to compensate the shortage of active oxygen on g-C₃N₄. g-C₃N₄ was found as a promising support for the high dispersion of Pt and MnO_x. Well dispersed Pt nanoparticles with an average diameter of 1.8 nm were obtained, which were highly favorable for the loading of MnO_x as MnO_x-Pt/g-C₃N₄. Catalytic performance results indicated that the limited HCHO conversion over g-C₃N₄ and Pt/g-C₃N₄ was significantly promoted with the introduction of MnO_x, with an optimum MnO_x amount of 3.0 wt%. The developed catalysts remained highly stable for 30 h. The enhanced catalytic activity of MnO_x-Pt/g-C₃N₄ was due to the increased number of active oxygen species with the introduction of MnO_x and the efficient transfer of electrons from g-C₃N₄ to Pt. Compared to the traditional impregnation, photodeposition process avoids the application of H₂ and high temperatures, scoring in favor of its green and safe nature. This study can concomitantly provide a new way for the design and fabrication of a non-metal oxide based support for the efficient HCHO catalytic oxidation and the application of the photocatalytic process in catalyst fabrication.