Enhanced catalytic performance of Pd catalysts supported on N-doped TiO2 for hydrogenolysis debenzylation of HBIW

Abstract

To address the high consumption and cost of noble metal catalysts during the production of hexanitrohexaazaisowurtzitane (HNIW, CL-20), nitrogen-doped titanium dioxide (TN) was synthesized using ammonium hydroxide as a nitrogen source. PdO/TN catalysts were then fabricated via a deposition–precipitation route and applied to the continuous hydrogenolysis debenzylation of hexabenzylhexaazaisowurtzitane (HBIW). Characterization by XRD, TEM, Raman spectroscopy, XPS, and H₂-TPR revealed that nitrogen incorporation effectively promoted the generation of surface oxygen vacancies and strengthened metal–support interactions, thereby enhancing catalyst stability. Moreover, the oxygen vacancy concentration could be tuned by adjusting calcination conditions. The PdO/TN-400-2 catalyst, prepared at 400 °C for 2 h, exhibited the highest catalytic activity, with an oxygen vacancy fraction of 19.64%. Further decreasing the calcination severity increased defect density but did not yield additional performance gains. These findings demonstrate that nitrogen doping can regulate surface defect chemistry and metal–support coupling, offering a viable strategy for the design of efficient catalysts for hexabenzylhexaazaisowurtzitane (HBIW) debenzylation.