Fabrication of AgCl@tannic acid-cellulose hydrogels for NaBH4-mediated reduction of 4-nitrophenol

A series of tannic acid (TA)-modified cellulose hydrogels embedded size-controlled AgCl nanoparticles (AgCl@TA(x)-cellulose hydrogels) were fabricated successfully via a one-step method. The size of AgCl nanoparticles in the TA-cellulose hydrogels could be adjusted expediently by varying the TA content. With the increase of TA content, the size of AgCl nanoparticles initially decreased and reached the minimum size of 5.5 nm at 5% TA content and then increased dramatically. The hydrogels with the smallest AgCl nanoparticles exhibited excellent catalytic activity in NaBH4-mediated reduction of 4-nitrophenol (4-NP); the reaction rate constant was as high as 1.383 min(-1). It should be noted that NaBH4 played a double role in the reduction of 4-NP presented here, i.e., in-situ reduction of AgCl to Ag nanoparticles and successive reduction of 4-NP over the resultant Ag@TA(x)-cellulose hydrogels. In such a way, the strategy of catalysis along with reduction provided a novel path for catalytic systems involving noble metal catalysts. Also, the above AgCl@TA(x)-cellulose hydrogels exhibited good catalytic activity for NaBH4-mediated reduction of various organic dyes following the procedure of catalysis along with reduction.

Automated summary

A series of tannic acid-modified cellulose hydrogels embedded with size-controlled AgCl nanoparticles were successfully fabricated, showing excellent catalytic activity in the reduction of 4-nitrophenol. The size of AgCl nanoparticles could be adjusted by varying the tannic acid content, with the smallest nanoparticles exhibiting the highest catalytic activity. The strategy of catalysis along with reduction provided a novel path for catalytic systems involving noble metal catalysts.