Nethravathi C, Rajamathi Michael
Materials Research Group, St Joseph's University, 36, Lalbagh Road, Bangalore, 560027, India.
Department of Chemistry, Mount Carmel College, Bangalore 560052, India.
Dalton Trans. 2024 Aug 20;53(33):14108-14116. doi: 10.1039/d4dt01647e.
Porous hexagonal nanoplatelets of mixed metal oxide (MMO) derived from the calcination of MgAl layered double hydroxide exhibits a CO sorption capacity of 1.99 mmol g at 30 °C, with a retention of 87% sorption capacity over 10 carbonation-decarbonation cycles and a CO sorption capacity of 1 mmol g at 200 °C with a 40% increase in capacity over 10 cycles. The high sorption capacity is attributed to the porous nanoplatelet structure of the MMO with a BET surface area of 115 m g, which enables increased CO diffusion. Upon partially replacing magnesium with calcium (33, 50 and 66 mol%), the CO sorption capacity of the MMO increases with an increase in temperature. MMO derived from LDH, in which 66% of magnesium is replaced by calcium (MgCaAl-66), delivers CO sorption capacities of 1.38, 1.31, 2.50, 4.85 and 7.75 mmol g at 200, 300, 350, 400 and 600 °C, respectively, which is significant for application in the sorption-enhanced water gas shift (SEWGS) process. MgCaAl-66 MMO exhibits a sorption capacity of 1 mmol g, which is stable over 10 cycles at 200 °C, and a sorption capacity of 3.68 mmol g at 400 °C with 85% capture efficiency retention over 10 cycles. While the incorporation of Ca serves multiple purposes such as increasing basic defect sorption sites and improving stability to repress the sintering-induced limitation of MMO over sorption cycles, the porous nanoplatelets act as individual sorbent units resisting volume changes through carbonation-decarbonation cycles.
由MgAl层状双氢氧化物煅烧得到的混合金属氧化物（MMO）多孔六边形纳米片在30°C时表现出1.99 mmol/g的CO吸附容量，在10次碳酸化-脱碳循环中吸附容量保留率为87%，在200°C时CO吸附容量为1 mmol/g，在10次循环中容量增加40%。高吸附容量归因于MMO的多孔纳米片结构，其BET表面积为115 m²/g，这使得CO扩散增加。用钙部分替代镁（33%、50%和66%摩尔比）后，MMO的CO吸附容量随温度升高而增加。由LDH衍生的MMO，其中66%的镁被钙替代（MgCaAl-66），在200、300、350、400和600°C时分别具有1.38、1.31、2.50、4.85和7.75 mmol/g的CO吸附容量，这对于吸附增强水煤气变换（SEWGS）过程的应用具有重要意义。MgCaAl-66 MMO在200°C时表现出1 mmol/g的吸附容量，在10次循环中保持稳定，在400°C时吸附容量为3.68 mmol/g，在10次循环中捕获效率保留率为85%。虽然掺入钙有多种作用，如增加碱性缺陷吸附位点和提高稳定性以抑制MMO在吸附循环中的烧结诱导限制，但多孔纳米片作为单个吸附剂单元，可抵抗碳酸化-脱碳循环中的体积变化。
