PdAg alloy nanowheats: Facile interfacial synthesis and highly selective catalysis in the hydrogenation of 4-nitrobenzaldehyde

Developing a simple and mild one-step method for the preparation of bimetallic nanomaterials with both free-standing features and excellent catalytic performance is highly desirable but remains technically difficult. Herein, a facile liquid-liquid interface route is exploited to grow the wheat-like PdAg nanostructures at the interface of chloroform and water under mild conditions without the use of any surfactants and supports. To implement this scheme, Na 2 PdCl 4 and AgNO 3 as precursors are dissolved in aqueous phase and α-naphthol as reducing agent in chloroform phase to build up the interfacial reaction system. At 40°C, the PdAg nanowheats are orderly grown, fused and assembled by many newly generated nanoparticles at the interface region, which have uniform shapes with the length of about 340 nm and the diameter of about 45 nm, abundant defects and strong electronic interaction between Au and Pd, as well as free-standing features. In the hydrogenation reaction of 4-nitrobenzaldehyde, PdAg-1 nanowheats exhibit excellent catalytic activity, selectivity and durability. Within 60.0 min of reaction at 35°C under atmospheric pressure, 99.8 % conversion of 4-nitrobenzaldehyde and 99.5 % selectivity toward 4-aminobenzaldehyde can be realized. After 5 cycles, 99.4 % conversion of 4-nitrobenzaldehyde and 98.0 % selectivity toward 4-aminobenzaldehyde can be maintained.