Which and how oxygen-containing functional groups on Ni@Graphene boost efficient hydrogenation via hydrogen spillover

Abstract

Unveiling the impact mechanism of oxygen-containing functional groups (OFGs) on the hydrogen spillover and hydrogenation process of metal-carbon composite catalysts is crucial yet challenging. Multiple hydrogenation sites on traditional supported catalysts complicate clarifying the role of OFGs. Herein, we fabricate a series of Ni@Graphene catalysts with different OFG contents and types to study the influence of OFGs on the hydrogen spillover and the hydrogenation activity. The investigation indicates that, among all OFGs, phenol and carboxyl groups play a leading role by reducing the energy barrier for hydrogen atom migration and show a significant linear correlation with hydrogen spillover capacity, the latter further linearly boosts the hydrogenation activity (increased by 193%–239%), which can serve as effective descriptor of the activities of Ni@Graphene. This study not only unveils which and how OFGs enhance hydrogen spillover and catalytic hydrogenation activity but also provides insights and new strategies for designing high-performance hydrogenation catalysts.