Non-noble metal nitrogen doped carbon material (M-N-C) catalysts are considered as potential alternatives for precious metals, due to their abundance, biocompatibility, environmental benign and high catalytic performance.

However, the current synthetic strategies for fabricating M-N-C catalysts via high-temperature pyrolysis unavoidably lead to a structural heterogeneity.

In order to obtain M-N-C with atomically dispersed active sites, a post-treatment is required to remove the inorganic metal-containing nanoparticles. This makes the whole synthesis complicated and environmentally unfriendly, and even damages the structure of M-N_x site.  

Recently, a research team led by Prof. YANG Yong from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences has developed a simple, economical and efficient high-temperature pyrolysis synthetic method. The study was published in ACS Applied Materials & Interfaces.

Using environmentally friendly biochar and inexpensive Cu (NO₃)₂ as the raw materials without post-treatment process, scientists have synthesized the atomic dispersed Cu-N-C catalyst. The atomic dispersion of coordinatively unsaturated Cu-N₂ sites is on biomass-derived hierarchically N-doped porous carbon with high specific surface area.

Fig.1 Schematic illustration of the synthesis and the characterizing result of Cu₁/NC-800 (Image by REN Peng) 

"This catalyst exhibits outstanding catalytic performance for Glaser-Hay coupling of terminal alkynes under base-free, ligand-free conditions by using air as oxidant," said REN Peng, a postgraduate student from QIBEBT and first author of the study. 

This protocol has addressed the poor selectivity issue in the synthesis of asymmetric 1,3-diyens, it's an important advancement to the field, commented by the peer reviewers. 

Fig. 2 Schematic illustration of single-atom Cu catalyst catalyzed Glaser-Hay coupling of terminal alkynes (Image by REN Peng)