Facile synthesis of porous PdCu nanoboxes for efficient chromium(vi) reduction

Abstract

Hollow porous nanostructures offer a multitude of advantages for heterogeneous catalysts over solid nanoparticle catalysts. Herein, we reported the facile synthesis of PdCu nanoboxes with porous shells through a Cu₂O template-assisted strategy, enabling efficient chromium-VI (Cr(VI)) reduction. The synthesis procedure involved the formation of well-defined Cu₂O nanocubes and the transformation of partial Cu₂O into a PdCu shell by a galvanic reaction. The structure/composition and formation mechanism of the PdCu nanoboxes were investigated in detail. When used as a heterogeneous catalyst, in the presence of formic acid (HCOOH), the PdCu nanobox demonstrated an excellent catalytic effect for Cr(VI) reduction with low activation energy (Ea = 47.8 kJ mol⁻¹) and a high kinetic constant (k = 0.274 min⁻¹). Moreover, the PdCu nanoboxes were recycled ten times without significant reduction in the transformation efficiency. The improved catalysis originated from the unique structure-/composition-dependent merits of the porous PdCu nanoboxes, which effectively promoted the dehydrogenation decomposition of HCOOH molecules.