Cu–N interface electron channel and photothermal synergistic catalysis enable more efficient selective oxidation of benzylamine to N-benzylidenebutylamine

In this study, the organic ligand material hexamethylenetetramine (HMT) was utilized as an electron acceptor integrated onto CuS, which was used to accelerate the charge transfer and thus improve the separation efficiency of photogenerated carriers to make its catalytic activity 2.26 times of the original. And it was used for the photothermal catalysis of benzylamine to realize the photothermal synergistic. [Display omitted] •A series of CuS-HMT catalysts with Cu–N interface electron channels were constructed.•Photothermal synergy and Cu–N channel can effectively enhance the activity of benzylamine to N-benzylidenebutylamine.•The optimized composite exhibited a yield of 30.28 mmol·g−1·h−1 and 98.73 % selectivity.•A mechanism for ligand-supported photothermal synergistic catalysis is proposed. Addressing inefficient photogenerated charge dynamics and insufficient activation energy is key to achieving the high activity and high selective in the conversion of benzylamine to N-benzylidenebutylamine. Herein, we present a synergistic catalytic strategy that couples the Cu–N electronic transfer channel formed between CuS nanoparticles and hexamethylenetetramine (HMT) ligands with photothermal catalysis for the efficient and selective oxidation of benzylamine to N-benzylidenebutylamine. XPS results and DFT calculations indicate that electrons from HMT are transferred to CuS through the N-Cu channel in the absence of light. Under illumination, to maintain interfacial charge balance, photogenerated electrons in CuS are transferred to HMT, which acts as an electron-rich medium, thereby promoting the separation of photogenerated charge carriers. Meanwhile, heating the reaction to 100 °C not only enhances the reaction rate but also accelerates charge transfer, further improving catalytic activity. The optimized CuS-HMT(0.02) sample achieves an N-benzylidenebutylamine yield of 30.28 mmol·g−1·h−1, which is 2.26 times higher than that of CuS alone, with a selectivity of up to 98.73 %. Finally, a photothermal catalytic mechanism for the oxidation of benzylamine to N-benzylidenebutylamine is proposed.