Hongtao Zou,Qilu Yao,Meiling Huang,Meihua Zhu,Fei Zhang,Zhang-Hui Lu
Hydrous hydrazine (N2H4·H2O) is considered a highly promising liquid chemical hydrogen storage material because of its high hydrogen content (8.0 wt%), simple byproduct (i.e., N2) and safe handling. In this work, noble-metal-free NiFe nanoparticles (NPs) supported on nano CeZrO2 solid solutions have been facilely synthesized and successfully applied as a highly efficient catalyst for the rapid and complete decomposition of N2H4 in aqueous solution. The turnover frequency (TOF) value of the NiFe/CeZrO2 catalyst for hydrogen generation from N2H4 reached 119.2 h−1 under alkaline conditions at 343 K, which is 28-fold higher than that of the benchmark catalyst, pure NiFe NPs (4.2 h−1). Moreover, the H2 selectivity and activity show almost no decrease after five runs, indicating that the prepared NiFe/CeZrO2 catalyst possesses high durability and stability under the current conditions. The high catalytic performance can be attributed to the synergistic electronic effect between NiFe NPs and nano CeZrO2 solid solutions, as well as small nanoparticles with highly dispersed active sites.
Ethylene production via chemical looping oxidative dehydrogenation (CL-ODH) of ethane faces a critical challenge in balancing conversion efficiency and selectivity due to competing oxygen species requirements. Here, we present a bifunctional composite catalyst (CrH/BiCZ) by physically integrating a Cr-HZSM5 (Cr-H) dehydrogenation (DH) catalyst with a Bi 2 O 3 -Ce 0.4 Zr 0.6 O 2 (Bi-CZ) selective hydrogen combustion (SHC) catalyst. This tandem system decouples ethane activation and hydrogen combustion, promoting the DH process of ethane through the in situ hydrogen combustion of the SHC catalyst. The Ce-Zr solid solution in Bi-CZ acts as an oxygen reservoir, enabling complete H 2 combustion within 3 min and suppressing carbon deposition. This rapid hydrogen combustion shifts the reaction equilibrium towards ethylene production. At 650 °C, the optimized CrH/BiCZ catalyst achieves 84.1 % ethylene selectivity at 43.0 % ethane conversion, and maintains exceptional stability over 36 redox cycles. This work establishes a scalable chemical looping strategy for efficient ethylene synthesis.
Guanling Yang,Haobo Wang,Aizhong Jia,Jingde Li,Yanji Wang
Hierarchically porous CexZr1−xO2 materials were prepared using a simple and scalable method of solvent volatilization and used in the direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol. The effect of cerium sources and the Zr-doping amount on the textural properties of the synthesized CexZr1−xO2 materials was investigated in detail. The characterization results indicated that the sample Ce0.9Zr0.1O2 had the largest specific surface area (152.1 m2 g−1) and the highest oxygen vacancy concentration (34%) and displayed the highest catalytic activity with a DMC yield of 257.14 mmol g−1. Zr-doping plays a key role in improving the catalytic properties and stability of the synthesized catalyst.
危险品化学品经营许可证（带存储）