Novel approach to immobilize Au nanoclusters on micro/nanostructured carbonized natural lotus leaf as green catalyst with highly efficient catalytic activity

Abstract

To achieve high catalytic activity and stability with low noble-metal loadings on green and natural supports has attracted tremendous attention in the past few years. Herein, a facile strategy is exploited to synthesize Au nanoclusters (with size of ∼1.4 nm) which are homogeneously distributed on carbonized natural lotus leaf sheets with less mass. Compared to the pure AuNCs, the AuNCs@carbonized lotus leaf (AuNCs@C-lotus leaf) micro/nanohybrid with the unique papillae structures and large surface area not only exhibits better catalytic activity for the reduction of 4-nitrophenol (4-NP), but also prevent the aggregation of AuNCs. In addition, the catalytic performance of AuNCs@C-lotus leaf catalyst increased with the temperature increasing of the reaction temperature. Moreover, the AuNCs@C-lotus leaf catalyst can be packed into a filtering platform to fabricate a fixed-bed system, with which the catalytic conversion could reach 71.7% for 0.2 mM 4-NP solution that pass through at flow rate of 1 mL/min. Furthermore, the AuNCs@C-lotus leaf catalyst shows excellent recyclability and only slight loss of catalytical activity is observed after recycling for five successive times. This mild and environmental friendly methodology could be generalized to the synthesis of other metallic nanoparticles@carbonized botanical leaf micro/nanohybrids as promising heterogeneous catalysts for varied catalytic reactions.