生物炭模板构筑Fe-Ni复合载氧体及其化学链制氢反应性能研究

采用松木热解生物炭为模板构筑Fe-Ni复合载氧体（Fe-Ni/BC），并与溶胶-凝胶法制备的NiFe₂O₄载氧体（NiFe₂O₄/SG）对比，采用SEM、XRD、XPS、BET、H₂-TPR、TG-redox循环等表征方法考察载氧体的物理、化学性质，并在固定床上进行化学链制氢循环实验。结果表明，Fe-Ni/BC载氧体为Ni_0.6Fe_2.4O₄与Fe₂O₃的混合晶体，保留了生物炭骨架并形成了大孔结构。与NiFe₂O₄/SG相比，Fe-Ni/BC平均粒径更小，比表面积更大，吸附氧含量更高，更有利于氧的释放。在固定床实验过程中，Fe-Ni/BC表现出更强的化学链制氢与抗积炭性能，其最大产氢速率是NiFe₂O₄/SG的1.58倍，制取H₂的相对浓度可达到99.5%以上。

Performance evaluation of Fe-Ni compound oxygen carriers derived from biochar template for chemical looping hydrogen generation

Fe-Ni oxygen carriers (Fe-Ni/BC) were prepared by using pine biochar as a template, and compared with NiFe₂O₄ oxygen carriers synthesized by sol-gel method. The obtained oxygen carriers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area measurement, hydrogen-temperature programmed reduction (H₂-TPR), and thermos-gravimetric redox-cycling (TG-redox). Furthermore, the performance of chemical looping hydrogen generation was investigated in a fixed-bed reactor. The results show that the prepared Fe-Ni/BC is a mixed crystal of Ni_0.6Fe_2.4O₄ and Fe₂O₃, retaining the framework of biochar and having a macroporous structure. Fe-Ni/BC outperforms NiFe₂O₄/SG in oxygen release, because of small average particle size, high specific surface area and abundant surface absorbed oxygen. In the fixed-bed tests, Fe-Ni/BC exhibits a better capability of hydrogen production and anti-carbon deposition with the maximum rate of hydrogen production for Fe-Ni/BC, 1.58 times that for NiFe₂O₄/SG, and the relative concentration of H₂ produced by Fe-Ni/BC is more than 99.5%.