深入了解用于 CO2 吸附和甲烷化的镍基双功能材料：还原温度的影响,Energy & Fuels

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深入了解用于 CO2 吸附和甲烷化的镍基双功能材料：还原温度的影响
Energy & Fuels ( IF 5.2 ) Pub Date : 2021-11-30 , DOI: 10.1021/acs.energyfuels.1c03008
Pu Huang ₁ , Yafei Guo ₁ , Guodong Wang ₁ , Jun Yu ₁ , Chuanwen Zhao ₁ , Xinru Wang ₂ , Tao Wang ₂

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Ni-MgO 双功能材料 (DFM) 显示出集成 CO ₂吸附和甲烷化的前景。为了提高 CO ₂吸附能力，Ni-MgO DFM 用碱金属硝酸盐促进。然而，高催化剂还原温度会导致高能耗、还原（~650°C）与CO ₂吸附和甲烷化（~300°C）之间的巨大温差以及碱金属硝酸盐的损失。在这项工作中，我们制备了一种 Ni/CeO ₂催化剂，并研究了还原温度对其在 CO ₂甲烷化中的结构-性质关系的影响，旨在将还原温度降低到与 CO ₂相匹配的等温水平。甲烷化。结果表明，还原温度从超过 650 ℃降至 300 ℃，并且在 300 ℃ 还原的Ni/CeO ₂具有高 CO ₂转化率（72.7%）和 CH ₄选择性（98.9%）。当还原温度超过400℃时，Ni/CeO ₂的CO ₂甲烷化活性显着下降。由于 NiO 和 CeO ₂之间的相互作用，形成更多的氧空位缺陷促进了 NiO 物种在较低温度下的还原。高还原温度下CO ₂甲烷化活性的下降归因于催化剂还原过程中氧空位的消耗，CO ₂可用的缺陷较少活化和甲烷化。碱金属硝酸盐促进的 MgO 吸附剂与 Ni/CeO ₂物理混合以构建 (Li-Na-K)NO ₃ -MgO-Ni/CeO ₂ -phy DFM，用于集成 CO ₂吸附和甲烷化。DFMs可以在300°C下轻松还原，这使得在集成CO ₂捕获和利用（ICCU）中实现催化剂还原和CO ₂吸附和甲烷化的等温操作成为可能。在 300 °C 还原的 (Li-Na-K)NO ₃ -MgO-Ni/CeO ₂ -phy DFM 表现出令人印象深刻的 CO ₂吸收量为 2.74 mmol CO ₂ /g DFM 和大量的 CH ₄1.10 mmol CH ₄ /g DFM 的产率，并且就其可比的 CO ₂吸附能力和甲烷化活性以及最低的原材料成本而言，它们可能是 Ru 基 DFM 的有前途的替代品。

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Insights into Nickel-Based Dual Function Materials for CO2 Sorption and Methanation: Effect of Reduction Temperature

Ni-MgO dual function materials (DFMs) show promise for integrated CO₂ sorption and methanation. To improve CO₂ sorption capacity, Ni-MgO DFMs are promoted with alkali metal nitrates. However, the high catalyst reduction temperature will result in high energy consumption, huge temperature gap between reduction (∼650 °C) and CO₂ sorption and methanation (∼300 °C), and the loss of alkali metal nitrates. In this work, we prepared a Ni/CeO₂ catalyst and investigated the effect of reduction temperature on its structure–property relationships in CO₂ methanation, aiming to lower the reduction temperature to an isothermal level that matches CO₂ methanation. Results indicated that the reduction temperature fell from over 650 to 300 °C, and Ni/CeO₂ reduced at 300 °C featured high CO₂ conversion (72.7%) and CH₄ selectivity (98.9%). The CO₂ methanation activity of Ni/CeO₂ declined significantly when the reduction temperature exceeded 400 °C. The formation of more oxygen vacancy defects due to the interaction between NiO and CeO₂ promoted the reduction of NiO species at lower temperatures. The declined CO₂ methanation activity at high reduction temperatures was ascribed to the consumption of oxygen vacancies in catalyst reduction, and less defects were available for CO₂ activation and methanation. An alkali metal nitrate promoted MgO adsorbent was physically mixed with Ni/CeO₂ to construct (Li-Na-K)NO₃-MgO-Ni/CeO₂-phy DFMs for integrated CO₂ sorption and methanation. The DFMs could be facilely reduced at 300 °C, and this has made it possible to realize the isothermal operation of catalyst reduction and CO₂ sorption and methanation in integrated CO₂ capture and utilization (ICCU). The (Li-Na-K)NO₃-MgO-Ni/CeO₂-phy DFMs reduced at 300 °C exhibited an impressive CO₂ uptake of 2.74 mmol CO₂/g DFMs and a great CH₄ yield of 1.10 mmol CH₄/g DFMs, and they could be a promising alternative to Ru-based DFMs with respect to their comparable CO₂ sorption capacity and methanation activity and minimized cost of raw materials.

更新日期：2021-12-16

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