Ensemble-Exciting Effect in Pd/alk-Ti₃C₂ on the Activity for Efficient Hydrogen Production

Abstract

Creating active sites to improve the mass activity and durability of metal catalysts by elucidating the relationship between the metal and the support is a major challenge. In this study, ultrafine palladium nanoparticles (Pd NPs) were supported on alkalized Ti3C2 (alk-Ti3C2) to obtain a catalytically active interfacial ensemble. The catalyst Pd/alk-Ti3C2 with a Pd loading of 1.0 wt % exhibited the highest activity in ammonia borane (AB) hydrolysis reaction, with an initial turnover frequency of 230.6 min–1. A comprehensive analysis revealed that an ensemble-exciting effect originated from the Pd and the alk-Ti3C2. The hydroxylation of alk-Ti3C2 regulated the local coordination environment of Pd. Water and AB were effortlessly activated by the −OH group and Pd atom aggregates composed of electron-deficient support alk-Ti3C2 and electron-rich Pd, respectively. The efficient generation of hydrogen at the interface of Pd/alk-Ti3C2 was further guaranteed by the interfacial activation. This work on precision active sites opens new avenues for developing high-activity noble-metal catalysts for AB hydrolysis.