Three-Dimensional Self-supporting AuPd Aerogel for Enhanced Catalytic Reduction of 4-nitrophenol

4-nitrophenol (4-NP) is a kind of hazardous aromatic compound, widely used in various industries. Catalytic reduction of 4-NP by metal nanoparticles (NPs) is an efficient method for the treatment of 4-NP from waste efflu-ent. Although many methods have been studied for the preparation of highly efficient metal NPs composites, the nano and/or micron particles of composites make it difficult to recover them after wastewater treatment, limiting their practical applications. Here, we prepared a three-dimensional self-supported AuPd aerogel, which not only showed high catalytic reduction activity against 4-nitrophenol, but also was easily recovered from wastewater and therefore could be reused. In our experiment, the reduction efficiency of 4-NP was not significantly reduced in 5 repeat cycles. The improvement of catalytic reduction performance of AuPd aerogels is mainly due to the following characteristics: (1) the connected channel and three-dimensional network provide a platform for accelerating mass transfer during the catalytic process; (2) metallic aerogel has a large surface area, which can provide enough reaction sites and high atomic utilization; (3) excellent catalytic activity was obtained due to the inherent synergistic effect of bimetals; (4) self-supporting characteristics are conducive to improving the durability of the catalyst. This study opens up a new way for the development of robust catalysts for heterogeneous catalytic reactions.