▎ 摘　　要

Promotion of the catalytic efficiency and reduction of the usage amount of Pd are crucial to developing effective and low-cost catalysts for catalytic reduction of organic aromatic nitro pollutant compound at present. Herein, we report a hybrid material of ultrafine Pd nanocrystals (PdNCs) grown on an excellent support of SnO2-decorated graphene nanosheets (SnO2-GNS) for a highly efficient reduction of a representative aromatic nitro compound (4-nitrophenol). The supporting material of SnO2-GNS was prepared simply by one step of homogeneous reaction with a positively charged polymer as stabilizer and active site for absorption of the PdNCs precursor. Transmittance electronic images demonstrate that the PdNCs are densely and well covered on the SnO2-GNS with a uniform size of 3.4 nm. This nanohybrid exhibits the fastest reduction time (4 minutes) compared to other controlled materials. Moreover, it shows high kinetic responses with an apparent kinetic rate constant (k(app)) of 2.03 x 10(-2) s(-1) and turnover frequency (TOF) of 1.70 s(-1). The cycle performance (10 times) experiments demonstrate that this nanohybrid also displays a good anti-poisoning capability. Thanks to the ultrafine PdNCs, this as-prepared PdNCs/SnO2-GNS nanohybrid may have broad potential in other catalytic fields, for example, organic synthesis, fuel cells and electrochemical biosensors.