【Frontiers in HaiChuan Chemical Technology】USTC overcomes the problem of easy sintering and deactivation of catalysts in methane dry reforming reactions

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According to the University of Science and Technology of China, the team led by Professor Ceng Jie at this university has overcome the problem of catalyst sintering and deactivation that occurs easily in the methane dry reforming reaction by developing catalysts with nano-island structures. The relevant research findings were published on March 10 in the international academic journal Nature Materials. Ultra-fine metal nanoparticles are highly favored in the field of heterogeneous catalysis due to their extremely high atomic utilization efficiency. However, during catalytic reactions, these nanoparticles are highly susceptible to factors such as high temperatures, which causes them to aggregate spontaneously and results in a decrease in activity; this process is known as sintering. Developing anti-sintering strategies for ultra-fine metal nanoparticles is a key challenge that urgently needs to be addressed in the field of catalytic science. In this research, based on a deep understanding of the sintering pathway, the researchers created a catalyst with a nano-island structure. Specifically, the researchers inserted uniformly distributed, small-sized, and non-connected metal oxide clusters between the carrier and the metal particles; these clusters were named nanoislands due to their island-like structure. Compared to carriers, nanodomes provide a stronger anchoring effect for metal particles, preventing the particles from migrating and sintering as a whole. Furthermore, the nanodots are not connected to each other, making it difficult for metal atoms that detach from the particle surface to migrate across the dots. By simultaneously blocking the two sintering pathways, the nanoid structure is expected to significantly enhance the anti-sintering performance of the catalyst. To construct catalysts with nano-island structures, researchers first established a strong adsorption force between the oxide and the carrier, thereby achieving small-sized, high-density oxide nano-islands through controlled agglomeration at high temperatures. By combining the principle of electrical matching with solvent evaporation, the researchers achieved precise placement of metals on the nanoislands. For common carriers, nanodots, and active metals, researchers have developed a material library of nanodot-structured catalysts. Among them, the silica-supported lanthanum oxide nanodisks exhibit a particularly prominent stabilizing effect on ruthenium nanoparticles. The researchers applied this catalyst to the methane dry reforming reaction to verify its sintering resistance. This reaction has attracted considerable attention due to its great potential in the resource utilization of greenhouse gases. Experimental results show that this catalyst can achieve stable conversion for 400 hours in a single run, and the size of the ruthenium nanoparticles remains at 1.4 nanometers after the reaction, effectively overcoming the problem of deactivation caused by factors such as high temperatures. By tailoring active metals and carriers, nano-island structured catalysts hold the potential to provide practical solutions to the sintering-induced deactivation problem encountered in various catalytic reactions.