The selective hydrogenation of alkynes to alkenes is an important transformation with applications in both the fine chemical industry (synthesis of vitamins and natural products) and polymer industry (selective removal of acetylene), where alloys are often employed as heterogeneous catalysts. Yet, advances in catalyst formulations that feature high activity, selectivity, durability and broad functional group tolerance and where both noble metals (e.g. Pd, Pt) and metals of environmental concern (e.g. Cd, Pb) are replaced by earth abundant and non-toxic metals are highly desirable. Here, we present the synthesis of uniform Ni-alloy nanocrystals (NCs), which are 3-4 nm in size and feature narrow size dispersions [1]. The nanocrystals are synthesized via an amalgamation seeded growth procedure [2], a generalized colloidal synthesis method developed by us for size and composition controlled nanocrystals of a wide range of alloys. The resulting catalysts are pristine, capped with non-poisoning oleylamine ligands and work as dispersions which are at the interface of homogeneous and heterogeneous catalysis. We find that Ni₃Zn NCs are particularly active and selective for the liquid-phase semi-hydrogenation of alkynes in batch, operating under mild reaction conditions. Furthermore, Ni₃Zn NCs are tolerant to a wide range of functional-groups, allowing the selective conversion of a broad scope of alkynes as studied with high-throughput experimentation. In addition, we show that the investigated substrate scope covers the chemical space of commercial alkynes to a large extend, as evaluated with data science techniques [1].

Figure 1. Investigation of NiZn Nanocrystal Catalyzed Alkyne Semihydrogenation Driven by Data Science and High-Throughput Experimentation.

Figure 2. Size- and Composition-Controlled Alloy Nanocrystals via Amalgamation Seeded Growth.