Differentially-grown cobalt regulators cooperatively involved in the tandem catalysis for high-yield production of second amines

One-pot tandem catalysis has been regarded as one of the most atomic economic ways to produce secondary amines, the important platform molecules for chemical synthesis and pharmaceutical manufacture, but it is facing serious issues in overall efficiency. New promotional effects are highly desired for boosting the activity and regulating the selectivity of conventional tandem catalysts. In this work, we report a high-performance tandem catalyst with maximized synergistic effect among each counterpart by preciously manipulating the spatial structure, which involves the active CeO2/Pt component as kernel, the densely-coated N-doped C (NC) layer as selectivity controller, and the differentially-grown Co species as catalytic performance regulators. Through comprehensive investigations, the unique growth mechanism and the promotion effect of Co regulators are clarified. Specifically, the surface-landed Co clusters (Cocs) are crucial to selectivity by altering the adsorption configuration of benzylideneaniline intermediates. Meanwhile, the inner Co particles (Cops) are essential for activity by denoting their electrons to neighboring Ptps. Benefiting from the unique promotion effect, a remarkably-improved catalytic efficiency (100% nitrobenzene conversion with 94% N-benzylaniline selectivity) is achieved at a relatively low temperature of 80 °C, which is much better than that of CeO2/Pt (100% nitrobenzene conversion with 12% N-benzylaniline selectivity) and CeO2/Pt/NC (35% nitrobenzene conversion with 94% benzylideneaniline selectivity).