Kelin Li,She Chen,Mengbo Li,Linlin Liu,Yunjie Li,Feng Wang
Ammonia is a promising carrier for energy storage due to its high hydrogen content, low storage and transportation costs, and zero carbon emissions. Plasma catalysis shows excellent potential for sustainable ammonia synthesis; however, searching for suitable catalysts is ongoing. La(OH) 3 was studied due to its rich basic sites and oxygen vacancies, which are beneficial for plasma-catalyzed ammonia synthesis. The optimal reaction conditions were investigated, and a maximum ammonia synthesis rate of 37.13 μmol/(min•g -cat ) was achieved. H 2 plasma treatment enhanced the catalytic activity of La(OH) 3 , and ammonia synthesis rate of 40.00 μmol/(min•g -cat ) were achieved. This study contributes to the development of efficient catalysts for plasma-catalyzed ammonia synthesis and highlights the potential of La(OH) 3 as a promising catalyst.
Yixuan Wang,Hongyan Ban,Yugao Wang,Ruwei Yao,Shimin Zhao,Jiangliang Hu,Congming Li
Basic sites profoundly affect the mode and strength of CO 2 adsorption in the hydrogenation of CO 2 to formic acid (FA), however, the mechanism by which the quantities and strength of basic sites affect the reaction process is not yet clear. Herein, a Ni/Mg a AlO x catalyst has been developed and the basic sites of the catalyst can be modulated by simply altering the Mg/Al ratio. Through a series of characterizations and experiments, it was observed that weak and medium basic sites synergistically catalyzed the hydrogenation of CO 2 to formic acid, and a reasonable number of weak basic sites can improve reaction performance when a sufficient number of medium basic sites guarantee the fundamental catalytic activity. Moreover, the number and distribution of basic sites are also tightly related to metal-support interactions. This strategy provides theoretical guidance and a feasible scheme for optimizing the performance of non-precious metal heterogeneous catalysts.
NO 2 is a potent air pollutant because of its deleterious effects on human beings and other organisms. The state-of-the-art catalysis-based deNO x techniques (e.g., selective catalytic/non-catalytic reduction) are incapable of ambient NO 2 abatement due to their low efficiency at temperatures below 300 °C. It is thus conceivable to directly capture NO 2 from the atmosphere by selective adsorption on porous materials. This work reports the rational development and demonstration of the Mg–Al layered double hydroxides (LDHs) and their derived mixed metal oxides (MMO), using environmentally benign solvents , as high-capacity adsorbents for ambient NO 2 abatement. By boosting the densities of accessible basic sites using layer delamination strategies, the highest NO 2 adsorption capacity of 8.52 mmol/g was achieved by the delaminated LDH material (LDH-AM), which was substantially higher than other popular and robust adsorbents, such as zeolites (0.36–3 mmol/g) and carbon-based adsorbents (2–6 mmol/g). Using Fourier transform infrared spectroscopy and powder X-ray diffraction, it was revealed that NO 2 adsorption occurs on the surface M-OH basic sites and within the layers by simultaneously replacing the interlayer CO 3 2− ions of LDH. This work affords not only promising, durable, and scalable adsorbents for ambient NO 2 removal but also a strategy to develop adsorbents with high density of basic sites for capture of other pollutant acid gases from the environment.
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