Iridium nanoparticles supported on hierarchical porous N-doped carbon: an efficient water-tolerant catalyst for bio-alcohol condensation in water.

Di Liu,Bo Dong,Chunhu Li,Yunfei Qi,Xindong Mu,Jing Guan,Quan Cao,Guoqiang Xu,Xiufang Chen

doi:10.1038/srep21365

Abstract

Nitrogen-doped hierarchical porous carbons were synthesized successfully by a controllable one-pot method using glucose and dicyandiamide as carbon source and nitrogen source via hydrothermal carbonization process. The nitrogen-doped materials, possessing high nitrogen content (up to 7 wt%), large surface area (>320 m2 g−1) and excellent hierarchical nanostructure, were employed as catalyst supports for immobilization of iridium nanoparticles for bio-alcohol condensation in water. The introduction of nitrogen atoms into the carbon framework significantly improved iridium nanoparticles dispersion and stabilization. The novel iridium catalysts exhibited superior catalytic activity in the aqueous phase condensation of butanol, offering high butanol conversion of 45% with impressive 2-ethylhexanol selectivity of 97%. The heterogeneous catalysts had great advantages of easy recovery and high catalytic stability. The outstanding catalytic performance could be attributed to excellent dispersion of iridium nanoparticles, stronger iridium-support interactions and interaction of nitrogen species with alcohol substrates.

Highlights

Been focused on exploring heterogeneous catalysts for alcohol condensation[14,15,16,17]
In this work, focusing on supported Ir nanoparticles as the catalytic agent, we synthesized a kind of nitrogen-doped carbon nanomaterials with glucose and dicyandiamide (DCDA) as carbon and nitrogen sources by hydrothermal carbonization (HTC) method and explored the as-made nanomaterials as basic supports to immobilize Ir catalyst for alcohol condensation in water
Nitrogen-doped carbons were synthesized by a facile HTC approach with DCDA as nitrogen source, which resulted in the formation of nanoporous structure and the uniform inclusion of nitrogen in the carbon matrix simultaneously

Summary

Introduction

Been focused on exploring heterogeneous catalysts for alcohol condensation[14,15,16,17]. Simple immobilization of the catalysts over activated carbon showed very poor activity for the self-condensation of butanol in aqueous phase When such Ir/C catalyst was combined with 1, 10-phenanthroline, which was directly added to the reactant mixture, the transformation could be promoted greatly. Wang et al prepared a porous nitrogen-doped carbon nanomaterial with glucose and nitrogen-containing ionic liquid as precursors by hydrothermal carbonization (HTC) method, which was an excellent support to construct Pd catalyst in the selective aerobic oxidation of alcohols and hydrocarbons[32]. In this work, focusing on supported Ir nanoparticles as the catalytic agent, we synthesized a kind of nitrogen-doped carbon nanomaterials with glucose and dicyandiamide (DCDA) as carbon and nitrogen sources by HTC method and explored the as-made nanomaterials as basic supports to immobilize Ir catalyst for alcohol condensation in water. The advantages including high activity, high stability, good recyclability and simple synthetic approach enabled the novel Ir-based nanomaterials as attractive heterogeneous catalysts for industrial application

Methods

Results

Conclusion