#hydroxides

Layered double hydroxides for oxygen evolution reactions

To guide the design and synthesis of electrocatalysts toward highly efficient oxygen evolution reactions (OER), researchers from the Beijing University of Chemical Technology have summarized four common strategies to improve the OER performance of layered double hydroxides (LDHs) as well as identifying active sites for LDHs.

They published their work on Sep. 7 in Energy Material Advances.

"With the rising demand and consumption of fossil fuels, energy shortage and environmental pollution are becoming severe and unignorable," said the corresponding author Mingfei Shao, professor with the State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing. "It is necessary to explore sustainable and renewable energy. Hydrogen, especially, is a new energy with splendid application prospects."

Production of highly pure hydrogen can be achieved by electrochemical water splitting using the electricity transformed from renewable energies such as wind and solar. But as one of the half reactions, OER is a four-electron process, with a low-efficiency energy utilization, according to Shaov

The first hydroxide conductivity in anion conducting polymer thin films

As decarbonization progresses rapidly in the world, fuel cells offer potentially higher electrical efficiency than conventional power-generating systems. Anion exchange membrane fuel cells offer advantages of using non-precious metal catalysts than proton exchange membrane fuel cells. One of the challenges of this next-generation fuel cell is to clarify the hydroxide ion conductivity in the ion conductive polymer around the electrode catalyst. The difficulty of studying the hydroxide ion conductivity at the electrode interface is that the hydroxide ion, which is a carrier, easily reacts with carbon dioxide in the air. To solve this problem, all evaluation devices were improved so that the sample did not come into contacting with air.

In a new study published in ChemSusChem, researchers from Japan Advanced Institute of Science and Technology (JAIST), namely Associate Professor Yuki Nagao and Ph.D. students Fangfang Wang and Dongjin Wang, succeeded in precisely identifying the hydroxide ion conductivity and the water amount contained in the sample without exposing the thin film sample to air. Fluorene-based cationic polymers were synthesized, and Br- and OH- samples as counter anions were prepared for comparison. It was revealed that the 270-nm-thick thin film containing hydroxide ions exhibits a high hydroxide ion conductivity of 0.05 S cm-1. This ionic conductivity was more than twice as high as the value of the thin film containing Br- ions as shown in Figure 1.

Sandwich is the food concocted by the 18th-ceuntry nobles to play card games uninterrupted. Meat or vegetables were layered then tucked between bread to be eaten quickly while engaged in the game. This efficient food also delivered ample calories and nutrition. POSTECH research team has discovered that layering like the sandwich is an excellent way to obtain hydrogen energy, an alternative energy source for fossil fuels.

The research team led by Professor In Su Lee, SunWoo Jang, a student in the MS/PhD integrated program, and Dr. Soumen Dutta of the Department of Chemistry at POSTECH have together developed a sandwich structured catalyst that can efficiently generate hydrogen energy by activating water electrolysis. The research findings were recently published in the American Chemical Society's international journal ACS Nano.

Hydrogen fuel cells are eco-friendly power-generating devices that generate electricity using chemical reactions that produce water (H2O) from oxygen (O2) and hydrogen (H2). With the recent release of hydrogen-powered vehicles and the spread of hydrogen fuel cells in households, hydrogen is widely seen as the next-generation energy source to replace fossil fuels. The way water is decomposed and hydrogen is produced using surplus current obtained from solar or wind power is considered the easiest and most eco-friendly way to produce high purity hydrogen fuel in large quantities. However, this method has a disadvantage of being low in production efficiency and high in cost. In order to lower the unit price of hydrogen fuel produced through water electrolysis, it is necessary to develop highly active and stable electrochemical catalysts that can maximize hydrogen generation efficiency.