Highly active CeO2-CuCo nanoparticles supported on hollow N-doped carbon spheres for boosting ammonia borane hydrolysis and tandem 4-nitrophenol reduction reactions

Abstract

It’s a safe method to use high hydrogen density ammonia borane (AB) to facilitate the tandem hydrogenation of aromatic nitro compounds. While a major problem for tandem hydrogenation, the development of non-noble metal catalysts with high activity and stability is encouraging. This work involved the synthesis of highly active CeO2/CuCo nanoparticles support on hollow N-doped carbon spheres and its investigation for AB hydrolysis, taking into account the impacts of the HNCSs and CeO2 supports. Because CuCo alloy, CeO2, and HNCSs supports worked in concert, HNCSs@CeO2/CuCo was found to be the best catalyst. The activation energy achieved was comparable to the reported Pd- and Pt-based catalysts, with a value as low as 21.8 kJ/mol. Using AB as the in-situ H2 source, HNCSs@CeO2/CuCo exhibited a significant degree of activity in the one-pot tandem reduction of 4-NP with the turnover frequency of 2830.2 h−1, even surpassing over ten times of some noble metal catalysts. Following five consecutive cycles of reaction condition tuning, the HNCSs@CeO2/CuCo catalyst demonstrated a constant conversion efficiency. Also, the catalyst's uses for one-pot tandem reduction of other highly active aromatic nitro compounds were expanded.