CO2捕集-转化一体化是实现烟气CO2减排和洁净能源高效存储的重要策略，也是加速实现碳中和的关键负碳排放技术，而兼具高CO2吸附容量和催化活性的双功能材料构筑是关键。基于碱金属熔盐修饰Ni/MgO双功能材料CO2吸附-甲烷化的技术路径备受关注。碱金属熔盐的稳定性和Ni活性组分的还原是提升熔盐修饰Ni/MgO双功能材料CO2吸附-甲烷化性能的关键。构筑了NaNO3修饰Ni/MgO一体化双功能材料，考察了还原温度对其CO2吸附-甲烷化一体化性能的影响规律。结果表明，双功能材料中的碱金属熔盐在低温条件下(～300 ℃)可促进CO2和MgO溶解扩散，提升CO2吸附性能，而较高的温度(>340 ℃)导致CO2和MgO溶解扩散受阻，熔盐组分迁移覆盖活性位点，致使材料攒聚烧结和熔盐分解，造成其吸附性能衰减。还原温度提高有利于NiO还原，可提高CH4产量、CO2转化率和CH4选择性。10NaNO3-Ni/MgO双功能材料(NaNO3负载量为10%（质量分数）)在450 ℃还原后，CO2吸附容量和转化率分别为6.46 mmol/g和79.37%，CH4产量和选择性分别为0.85 mmol/g和96.27%。综合考虑还原温度对CO2吸附和甲烷化性能的影响，提出了高浓度H2低温还原的补偿策略，在维持碱金属熔盐稳定和CO2吸附性能的条件下提升双功能材料的甲烷化性能。

The integration of CO2 capture and utilization (ICCU) is an important strategy to realize CO2 emissions reduction and clean energy storage. It has been also recognized as a key negative emission technology (NET) to accelerate the realization of carbon neutrality. Dual function materials (DFMs) with both high CO2 uptakes and excellent catalytic activity are the key to realizing the ICCU scheme. The integrated CO2 capture and in-situ methanation (ICCU-M) process based on Ni/MgO DFMs promoted by alkali metal salt (AMS) has attracted broad attention. The stability of AMS and the reduction of NiO active components are critically important for improving the CO2 adsorption methanation performance of Ni/MgO bifunctional materials modified with molten salts. In this work, NaNO3-promoted Ni/MgO DFMs were prepared and the influence of reduction temperature on ICCU-M performance was investigated. The results indicate that the doped AMS can promote the dissolution and diffusion of CO2 and MgO at low temperatures (～300 ℃), and improve the CO2 adsorption performance. Due to the high temperature (>340 ℃), the dissolution and diffusion of CO2 and MgO are blocked, and the migration of molten salt components covers the active site, resulting in the accumulation and sintering of materials and the decomposition of molten salt, and the attenuation of their adsorption performance. Increasing reduction temperature favors NiO reduction, which can increase CH4 yield, CO2 conversion and CH4 selectivity. After reduction at 450 ℃, the CO2 adsorption capacity and conversion rate of the 10NaNO3-Ni/MgO DFMs (NaNO3 loading of 10%) are 6.46 mmol/g and 79.37%, and the CH4 yield and selectivity are 0.85 mmol/g and 96.27%, respectively. Given the impact of reduction temperature on CO2 capture capacity and methanation activity, a compensatory strategy of catalyst reduction under low temperature and high H2 concentration was put forward, to boost the methanation activity of the DFMs while maintaining the stability of AMS and CO2 adsorption performance. 

0 引言

1 试验

   1.1 材料制备

   1.2 材料表征

   1.3 材料性能测试

2 结果与讨论

   2.1 样品微观结构表征分析

   2.2 CO2吸附性能

   2.3 CO2甲烷化性能

   2.4 CO2吸附-甲烷化性能

3 结论