Significant enhancement in activity of Pd/TiO2 catalyst for formaldehyde oxidation by Na addition

Abstract

Developing an effective material for indoor HCHO elimination at ambient temperature is of great significance. In this work, a series of Pd/TiO2 catalysts with different Na loadings were prepared and tested for their activity in HCHO oxidation. The results indicated that Na addition had a remarkable promotion effect on Pd/TiO2 catalysts for HCHO oxidation, and the optimal Na loading was 2wt.%. Features of the catalysts including the reducibility, Pd dispersion and valence state of Pd and O were elucidated using a variety of characterization techniques. The results showed that 2.0Na-Pd/TiO2 exhibited more exposure of active Pd sites and contained abundant surface OH groups, giving it the best HCHO catalytic oxidation performance of the studied catalysts. The 2.0Na-Pd/TiO2 catalyst also had high resistance to effects of space velocity and relative humidity (RH), maintaining high HCHO conversion over a wide gas hourly space velocity range of 80,000–190,000h−1 and RH of 25%–65%.