CHEMICAL SCIENCE

Ethane and hydrogen are prepared with high selectivity from natural gas


The research team of Professor Xiong Yujie and Professor Long Ran of the University of Science and Technology of China, together with Associate Researcher Fu Cenfeng of Academician Yang Jinlong’s team, and Professor Yao Yingfang of the Academician Zou Zhigang Team of Nanjing University, innovated the catalyst design of photocatalytic methane oxygen-free coupling, realizing the highly selective preparation of ethane and hydrogen, and the efficiency reached the level of anaerobic coupling of methane in medium temperature and heat. The results of the research were published in Nature Communications.

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Methane oxygen-free coupling photocatalysts supported by single-atom coordination Courtesy of the University of Science and Technology of China

Methane is the main component of natural gas, combustible ice, biogas, etc., and is widely distributed in nature. How to convert the huge reserves of methane resources into fuels or chemical products with higher economic added value has important scientific significance and application prospects.

Photocatalytic methane oxygen-free coupling methods, which allow direct conversion of methane under mild conditions, while obtaining both polycarbons and hydrogen, are an attractive route.

Xiong Yujie introduced, “On the one hand, the photocatalytic methane oxygen-free coupling method does not require the two-step indirect conversion method of mature methane reforming and Fischer-Tropsch synthesis, which avoids the shortcomings of complex process, large energy consumption and high production cost. On the other hand, this method does not require harsh reaction conditions and avoids excessive oxidation of methane to form a large number of carbon dioxide and other by-products. ”

At present, the photocatalysts commonly used for methane oxygen-free coupling are mainly metal oxide semiconductor materials. Xiong Yujie said, “The lattice oxygen atoms in the photocatalyst are very easy to over-oxidize methane, so it will still produce some carbon monoxide, carbon dioxide and other by-products, and cause the catalyst to be completely inactivated.” ”

In order to solve this problem, Xiong Yujie and Long Ran’s team proposed to regulate the valence band electronic structure of the photocatalyst by means of single-atom coordination loading, forming a very stable coordination structure of single atom and lattice oxygen, avoiding the direct participation of lattice oxygen atoms in the photocatalytic methane oxygen coupling reaction, thereby improving the photocatalytic methane oxygen-free coupling performance while reducing the degree of excessive oxidation of methane.

Based on this strategy, the research team achieved 0.7 grams of ethane per gram of catalyst per day, with a selectivity of 94.3%, while also producing the same proportion of hydrogen. The researchers further improved the stability of lattice oxygen in the catalyst by doping the elements, thereby prolonging the stability of the catalytic performance, providing a new idea for the development of efficient photocatalytic methane oxygen-free coupling catalysts.

According to the reviewers, “The work made it possible to convert methane to ethane in a photocatalytic pathway, demonstrating the charm of single-atom catalysts.” (Source: China Science Daily Wang Min)

Related paper information:https://doi.org/10.1038/s41467-022-30532-z



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