In a study published in Nature Energy on June 3, Prof. SONG Li and Prof. JIANG Jun from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences reported their ingenious design of a pin-point catalyst with pine-ball structure using platinum metal. Compared with commercial platinum-carbon catalysts, the amount of platinum metal was reduced by nearly 75 times and the cost of the catalyst was greatly reduced while the catalytic hydrogen production remained almost unchanged.

In the story of Hongloumeng (The Story of the Stone), a few people are busy in Jiafu while most people have nothing to do. Similar problem exists in traditional catalysts for hydrogen generation. Catalytic processes generally occur on the surface of catalysts and involve a single or several neighboring atoms. The platinum atoms on the surface manufactured in the traditional way are very busy, while the platinum atoms inside contribute little. To make these platinum atoms in catalysts move without eating from the same pot, Prof. SONG's team came up with a idea to maximize the platinum atoms on the surface of catalysts.

They first chose the sphere with the largest surface per unit mass, and made the flat catalysts into "spheres" one by one, transforming the previously confined two-dimensional reactions into three-dimensional. Once a small bungalow was transformed into a spherical high-rise, and the number of people that could be accommodated-that is, the site where reactions could take place-increased greatly. At the same time, each platinum atom is located on the spherical surface, which ensures that they are on the "production line". In this way, the catalyst forms a "ball" full of needle tips, each of which is a single atom of platinum, and no "human" can "hide" behind.

"This design also brings a surprising additional effect. Theoretical simulation shows that the curved sphere will form a very strong local electric field at the tip of the platinum atom, which is equivalent to adding an accelerating track to the foot of platinum atom, resulting in further enhancement of the catalytic efficiency." Prof. JIANG said.

The rate of hydrogen formation increases greatly when the reactants in the electrolytic solution pass through the "loose balls" of needle tips on one surface after another. "With the same hydrogen production, the catalyst we designed only needs one platinum, while the traditional commercial platinum-carbon catalyst needs seventy or eighty platinum, which greatly reduces the cost of the catalyst." Prof. SONG said.

Platinum metal plays an important role in hydrogen generation by water electrolysis reaction. This study minimizes the amount of platinum without affecting the catalytic effect of hydrogen evolution reaction, and points out the direction for further optimizing the performance of catalyst.

Hydrogen energy is an efficient and clean energy. Hydrogen generation by water electrolysis has attracted great attention because of its advantages of zero emission and zero pollution.

The design of the structure of platinum atom catalyst, which greatly improves the hydrogen generation efficiency of electrolytic solution when it passed through pinpoint catalyst "pine ball". (Image by LI Jin)