Layer-dependent catalysis of MoS2/graphene nanoribbon composites for efficient hydrodesulfurization

Abstract

Graphene nanoribbons (GNRs) derived from the unzipping of carbon nanotubes are used as a catalyst carrier for MoS₂ with different layers via a facile solution route. Efficient hydrodesulfurization (HDS) of carbonyl sulfide (COS) has been achieved over the MoS₂/GNR composites. It is revealed that single layer MoS₂ anchored on GNRs (SL-MoS₂/GNRs) is successfully fabricated by the assistance of cetyltrimethylammonium bromide (CTAB). The catalytic activities of the SL-MoS₂/GNRs, few-layer MoS₂ supported on GNRs (FL-MoS₂/GNRs) and pure MoS₂ with a multi-layer structure (ML-MoS₂) are investigated, and the layer-dependent catalytic activity of MoS₂ has been demonstrated in the hydrogenation of COS. The order of the catalytic performance for the three catalysts is SL-MoS₂/GNRs > FL-MoS₂/GNRs > ML-MoS₂, especially within a low temperature range (180–280 °C) of the HDS reaction. The superior catalytic activity of SL-MoS₂/GNRs can be ascribed to the high density of the active sites in single-layer MoS₂. Due to the edge effect of GNRs, single layer MoS₂ supported on GNRs is thinner and shorter than MoS₂ anchored on graphene nanosheets (GS). The synergy between single layer MoS₂ and GNRs may be mainly responsible for the better catalytic performance of SL-MoS₂/GNRs. This work offers a feasible strategy for the synthesis of single-layer MoS₂ supported on GNRs for efficient HDS application.