MOF-templated fabrication of Ni@C/g-C3N4 catalyst with high-dense accessible active sites achieving dicyclopentadiene hydrogenation at ambient conditions and comprehensive mechanism insight

The catalytic hydrogenation of dicyclopentadiene (DCPD) is one of the pivotal processes in the production of green high-energy-density liquid hydrocarbon fuels, jet propellent-10 (JP-10). However, the high dependency of the current catalysts on high temperature and pressure, whether the non-noble (>120 ℃, >15 bar) or even the noble catalyst (80 ℃, >7.6 bar), leads to enormous energy consumption and technical challenges in environment and sustainable development. Herein, we prepared a carbon layer wrapped Ni nanoparticles/g-C 3 N 4 catalyst (Ni@C/g-C 3 N 4 ) derived from the in-situ-formed Ni-MOF/g-C 3 N 4 composite. Benefiting from the 53.2 wt% small-sized Ni nanoparticles and nanosheet structure, resulting in high-density accessible active sites (5.38 × 10 20 sites g −1 ) and the mass transfer enhancement, Ni@C/g-C 3 N 4 achieved DCPD hydrogenation under ambient conditions. > 99.9 % DCPD conversion and 98.1 % endo -tetrahydrodicyclopentadiene yield was obtained at 30 ℃, 1 bar, significantly outperforming the benchmark 5 % Pd/C. To the best of our knowledge, it’s the mildest condition for DCPD hydrogenation. Further, comprehensive mechanistic insights were gained from combining means of kinetic investigations, in situ characterization, and theoretical calculations. The discrimination result of 27 kinetic models indicated that DCPD hydrogenation followed the Langmuir-Hinshelwood-Haugen-Watson formulism regarding the reaction between the chemisorbed dihydrodicyclopentadiene (DHDCPD) and dissociatively adsorbed hydrogen as the rate-determining step. In-situ DRIFTS confirm that the norbornene ring is preferentially adsorbed and hydrogenated. The DFT calculations further substantiate the hydrogenation pathway. The present work provides guidance for the development of highly efficient non-noble metal catalysts and opens up an environmental-friendly and economically viable avenue for DCPD hydrogenation.