Nanostructured bimetallic Zn/Co in N-doped carbon as an efficient catalyst for the alcohol dehydrogenation to carboxylic acids under solvent-free conditions

The catalytic alcohol dehydrogenation to carboxylic acids has been demonstrated as an atom-economic and environmental-friendly synthetic method. However, the reported catalysts either require relatively complicated synthesis or exhibit high activity only in the presence of a solvent. Therefore, it is still in high demand to obtain catalysts that feature facile synthesis and perform well even without any solvent. Herein, a series of nanostructured bimetallic Zn/Co species embedded in N-doped hierarchical porous carbon were fabricated in a facile and green manner. More significantly, the best-performing material (Zn/Co@NC-800) was identified as the first heterogeneous catalyst to enable this transformation under solvent-free conditions. Moreover, the as-prepared composites were comprehensively investigated to determine their structural and morphological properties, which rationalized the superiority of Zn/Co@NC-800 over the other synthesized materials. Further studies signified that Co sites (both Co 0 and Co 2+ ) and N species (mainly pyridinic N) were probably involved in this process, functioning as the Lewis acid site and basic site, respectively. Hopefully, this study could provide a simple and sustainable method for carboxylic acid synthesis.