Design of highly efficient and carbon-resistant catalysts for biogas reforming using entropy engineering strategy.

Methane reforming yields syngas with H2/CO ratios of 1 or 3, whereas the optimal ratio for methanol synthesis is 2. However, during long-term reforming, catalysts suffer deactivation from sintering and carbon deposition. Consequently, a general catalyst design principle tailored to industrial methanol synthesis is urgently needed. This study synthesized a high-entropy catalyst, NiLaMgAlCaCeOx, via mechanochemical ball milling, employing entropy engineering for Gibbs free energy reduction. The reforming performance of this high-entropy catalyst was evaluated using simulated biogas. An H2/CO ratio suitable for methanol production was achieved by adjusting H2O addition, and performance was compared with control catalysts. XPS, SEM, TEM, H2-TPD, TG, and FTIR techniques elucidated the high-entropy catalyst's anti-sintering and carbon deposition resistance mechanisms. Results indicated that the high-entropy oxide structure in NiLaMgAlCaCeOx possesses high configurational entropy, which effectively restricts high-temperature active component migration and efficiently facilitates deposited carbon removal, preventing deactivation. This structure confers superior activity and stability compared to the control NiLaCeOx. Specifically, its reforming stability under simulated biogas surpassed that of control catalysts NiLaMgAlCeOx, NiLaMgCeOx, and NiLaCeOx. The key resistance against sintering and carbon deposition lies in high CO2 and H2O adsorption energy on the highentropy catalyst, coupled with multi-metal composition limiting Ni migration at elevated temperatures. This high-entropy stabilization mechanism, promoting resistance to sintering and mitigation of carbon deposition, offers valuable insights for future industrial methanol catalyst design.