Immobilizing PdAuIr Nanoclusters on Lamellar MOF for Formic Acid Dehydrogenation and Hexavalent Chromium Reduction

Ultrafine metal nanoclusters (NCs) have demonstrated high catalytic efficiency in the hydrogen production process via the formic acid dehydrogenation (FAD) reaction. Nevertheless, designing multimetal nanocluster catalysts that combine high activity with robust stability remains a significant challenge. In this work, PdAuIr ternary alloy NCs with an average size of 1.9 nm were uniformly anchored onto an amine-functionalized layered Ni-based metal–organic framework (Ni-BDC-NH2) using a straightforward impregnation–reduction method. Experimental results indicate that the coexistence of Au and Ir effectively modulates the electronic structure of the active Pd centers, leading to a notable enhancement in the catalytic reaction rate. Ni-BDC-NH2 facilitates the contact of formic acid molecules with active sites through its multilayer, porous architecture. The surface-grafted amino groups also contribute to obtaining a well-dispersed and stable distribution of the PdAuIr NCs. The resulting PdAuIr/Ni-BDC-NH2 catalyst exhibits exceptional performance in the FAD reaction, achieving a turnover frequency (TOF) of 11969 h–1 without additives at 323 K. Moreover, the rate constant for the reduction of hexavalent chromium (Cr(VI)) reaches 0.53 min–1 at 298 K, outperforming most reported counterparts. This study offers a strategy for the rational design of highly efficient multimetal nanocluster catalysts.