Hydrogen peroxide is one of the world's top 100 industrial chemicals with a wide range of applications in the chemical, medical, and semiconductor industries. Currently, hydrogen peroxide is mainly produced through the anthraquinone process, but this process has several problems, including high energy consumption, the use of expensive palladium catalysts, and environmental pollution due to by-products. In recent years, an environmentally friendly method of producing hydrogen peroxide by electrochemical reduction of oxygen using inexpensive carbon catalysts has gained attention. However, this method has been limited by the high cost of injecting high-purity oxygen gas and the practical limitations that the generated hydrogen peroxide is mainly produced in an unstable basic electrolyte environment.
To overcome this limitation, a team of researchers led by Dr. Jong Min Kim, Center for Extreme Materials Research Center, Korea Institute of Science and Technology (KIST) , Dr. Sang-rok Oh, Center for Computational Science, Dr. Sang Soo Han, Center for Computational Science, Prof. Kwang-hyung Lee, Korea Advanced Institute of Science and Technology (KAIST), and Dr. Joonhee Moon, Korea Basic Science Institute (KBSI), developed a highly efficient mesoporous catalyst that can effectively produce hydrogen peroxide even in air supply environments with low oxygen concentrations and neutral electrolytes by introducing mesopores into the carbon catalyst.
The team synthesized boron-doped carbon with mesopores of about 20 nanometers (nm) by reacting the greenhouse gas carbon dioxide (CO₂), the potent reducing agent sodium borohydride (NaBH₄), and meso-sized calcium carbonate (CaCO₃) particles, followed by selective removal of the calcium carbonate particles. Using it as a catalyst for electrochemical hydrogen peroxide production, experiments and calculations have shown that the curved surface characteristics formed by the mesopores provide excellent catalytic activity even in neutral electrolyte environments, where hydrogen peroxide production reactions are difficult. Furthermore, real-time Raman analysis has confirmed that the mesoporous structure facilitates the smooth transfer of oxygen as a reactant, allowing high catalytic activity to be maintained even in air environments with an oxygen concentration of only about 20%.
Based on these findings, the team demonstrated that boron-doped mesoporous carbon catalysts, when applied to a hydrogen peroxide mass production reactor, can achieve world-class hydrogen peroxide production efficiencies of more than 80% under near-commercial conditions of neutral electrolyte and air supply and industrial-scale current density (200 mA/cm²). In particular, the team succeeded in producing hydrogen peroxide solutions with a concentration of 3.6%, which exceeds the medical hydrogen peroxide concentration (3%), suggesting the possibility of commercialization.
"The mesoporous carbon catalyst technology, which utilizes oxygen from the air we breathe to produce hydrogen peroxide from a neutral electrolyte, is more practical than conventional catalysts and will speed up industrialization," said Dr. Jong Min Kim of KIST.
