Tianjin University published papers on boride derived oxygen production catalysts

Source: New Materials Science News



Recently, Professor Liang Hongyan and Professor Liu Yongchang from Tianjin University cooperated with Professor Edward h. Sargent from the University of Toronto in Canada to publish a research article entitled "border derived oxygen evolution catalysts" on the internationally renowned journal Nature communications.

Metal borides / borates are considered to be promising electrocatalytic catalysts for water decomposition and oxygen evolution; However, so far, it is difficult to achieve the current density and stability of commercial operation. In this paper, the metal structure team proposed a method to prepare high-performance boride / borate based catalysts. By combining theoretical calculation simulation and in-situ characterization (synchrotron radiation and X-ray diffraction) technology, it is found that the new characteristics of metal borides, that is, the in-situ formation of metal salts (nife-b to nife-b-o) in the process of electrocatalytic reaction, can significantly improve the electrocatalytic activity of the catalyst.

This research article analyzes the reasons why the boron based compound oxygen production catalysts commonly used now are unstable under high current performance. At the same time, it is confirmed that the borate formed in situ by the metal boride is the reason for high catalytic activity through operando spectral characterization, and it shows high stability in the commercialized hydrolysis and electrocatalytic co reduction tests.

Fig. 1. Changes of NiFe Froude diagram and oer reaction energy before and after boride addition.

In this paper, the reason why boride catalyst has good performance in oxygen production reaction is explained. Using in-situ X-ray characterization method, the transition from b-compound to B-Acid salt can be observed. Combined with theoretical calculation and Fourier diagram, high-performance and Stable Ni and Fe based borates can be obtained. In addition, the high catalytic oxygen production performance of NiFe based boride catalyst was also verified. In this paper, NiFe based boride catalyst was prepared by chemical reduction method, and its electrocatalytic oxygen production performance was characterized on three-dimensional foam nickel substrate. The results show that the boride derived oxide catalyst can reach 167 MV over potential in 10 ma/cm2 current density and 1 m KOH electrolyte.

This technology is conducive to commercial application. In the electrocatalytic water decomposition device, the overpotential reached a record breaking value of 460 MV when operating at a high current density of 1 a/cm2 for 400 hours. In addition, the catalyst is combined with the co reduction reaction and assembled into an alkaline environmental membrane electrolytic cell, which can stably carry out C2H4 electrocatalytic synthesis for 80 hours at a current density of 200 ma/cm2. The energy efficiency of C2H4 electrocatalysis is 19%, compared with that of C2H4 electrocatalysis when IrO2 is used for oer reaction in the conditions, which is only 17%.

First authors: Wang Ning, Xu Aoni, Ou Pengfei, Hong Songfu

Corresponding authors: Liang Hongyan *, Liu Yongchang *, Edward h. Sargent*

Setting: Tianjin University, University of Toronto, Canada

[article link]

“Boride-derived oxygen-evolution catalysts”

https://www.nature.com/articles/s41467-021-26307-7.pdf