Copper doping allows a h

image: To produce safer, more economical and more environmentally friendly hydrogen peroxide, an international research team turned to copper.
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Credit: Nano Research

Hydrogen peroxide, the household antiseptic commonly used to clean cuts and scrapes, can also power space shuttles. While the version sold in pharmacies is much less concentrated than that used in industry, the simple reduction of two atoms of hydrogen and two atoms of oxygen in water and additional oxygen can produce great results. Production of the compound is expensive, however, requiring expensive metals to initiate the necessary chemical reactions which, when left unchecked, can produce unintended explosions.

To produce safer, more economical and more environmentally friendly hydrogen peroxide, an international research team turned to copper. The base metal has reduced the number of manufacturing steps, making the resulting hydrogen peroxide more stable, efficient and cost-effective. They published their work on January 11 in Nano-research.

Hydrogen peroxide is considered a high-value oxidant – a substance that can accept electrons from other substances, according to article author Qian Liu, an associate professor at the Institute for Advanced Study of Chengdu University. It is traditionally produced by a multi-step process in which an expensive metal, such as palladium, reacts electrochemically with a chemical compound containing hydrogen and oxygen to reduce the electrons of oxygen by four to produce hydrogen peroxide and unwanted organic waste.

“The four-electron reduction process generates hydrogen peroxide and water – there is competition between the two processes,” Liu said. “As such, in the process of designing and preparing catalysts, we must satisfy a two-electron reaction process to selectively produce as much hydrogen peroxide as possible to reduce unnecessary energy losses.”

The researchers chose to use titanium dioxide as an abundant, non-toxic and stable catalyst, but need to improve it to achieve a two-electron reaction process.

“We doped titanium dioxide with copper to naturally increase the concentration of vacant oxygen, leading to better electronic conductivity and better generation of hydrogen peroxide,” said paper author Shihai Yan. , associate professor at the College of Chemistry and Pharmaceutical Sciences of Qingdao Agricultural University.

The copper serves as a heteroatom, allowing researchers to manipulate the electronic structure of titanium dioxide. This enhanced catalyst can then create new atomic gaps in the reducing compounds, favoring one product over another. For example, during the electrochemical reduction of molecular hydrogen and oxygen, the addition of copper helps create more points for oxygen to bond with hydrogen to produce hydrogen peroxide. Instead of a competition for the constituents to become water or hydrogen peroxide, the latter gets a boost, while the rest burns off as gas. When the process is contained in a liquid, it is a relatively harmless side effect.

“The two-electron electroreduction of oxygen to hydrogen peroxide in an aqueous environment provides a safe, sustainable and energy-efficient method for on-demand production,” said Xuping Sun, a professor at the Institute of Science fundamentals and frontiers of the University of electronic sciences and technologies. from China

“Copper-doped titanium dioxide exhibits significantly improved selectivity of up to 91.2% for hydrogen peroxide, which means that most components reduce to the desired product. Moreover, it also shows higher yield and good stability.

Next, the researchers plan to design and synthesize copper-doped titanium dioxide catalysts against practical requirements to achieve large-scale industrial production.

This study provides a new way to tune the electronic structure of metal oxide by heteroatomic doping as high-efficiency electrocatalysts for the oxygen reduction reaction to produce hydrogen peroxide,” Liu said.

Other contributors include co-first author Zhiqin Deng, co-first author Li Li, Yuchun Ren, Je Liang, Kai Dong and Tingshuai Li, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China; Chaoqun Ma, College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University; Yonglan Luo, Institute of Advanced Study, Chengdu University; Bo Tang, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University; Yang Liu and Shuyan Gao, School of Materials Science and Engineering, Henan Normal University; and Abdullah M. Asin, Department of Chemistry, Faculty of Science and Center of Excellence for Advanced Materials Research, King Abdulaziz University.

The National Natural Science Foundation of China supported this work.

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On Nano-research

Nano-research is an international and interdisciplinary peer-reviewed research journal, sponsored by Tsinghua University and the Chinese Chemical Society. It offers readers an engaging mix of comprehensive, authoritative reviews and cutting-edge original research articles. After more than 10 years of development, it has become one of the most influential academic journals in the nano field. Quick review to ensure quick release is a key feature of Nano-research. In 2020 InCites Journal Citation Reports, Nano-research has an impact factor of 8.897 (8.696, 5 years), the total number of citations reached 23,150 and the number of highly cited articles reached 129, ranked in the top 2.5% of more than 9,000 journals academics, ranking first among China’s international academic journals.

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Norma A. Roth