The use of high temperature induced by solar thermal conversion (STC) instead of traditional heating methods to drive catalytic reactions is of great significance for reducing carbon emission and establishing green catalytic technology. However, traditional solar thermal materials typically do not have high catalytic activities, which limits the utilization efficiency of solar thermal energy in catalysis. Thus, developing the solar-thermal catalyst that combines high absorptivity of solar spectrum, high STC efficiency and excellent catalytic activity to achieve efficient light harvesting and STC at the catalytic site is a key but challenging task.
Recently, a research group led by Prof. DENG Dehui from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) developed a high-performance solar thermal catalyst by using Chainmail catalyst to build a hierarchical nanocage structure, which achieves highly efficient STC and significantly boosts oxygen evolution reaction (OER). This study was published in Angewandte Chemie International Edition and was selected as the back cover paper.
Schematic illustration (left) and back cover (right) of the STC-enhanced oxygen evolution on the CoNi@Gr-nanocage catalyst (Image by XU Mingxia)
The researchers synthesized a chainmail catalyst composed of graphene-encapsulated CoNi nanoalloy. They found that the electronic interaction between CoNi and graphene increases the electron density of states in the valence and conduction bands of graphene, which not only stimulates high catalytic activity but also enhances the light absorptivity and STC efficiency of the graphene layer.
Inspired by the black-body radiation, the researchers further fabricated a hierarchical nanocage structure composed of the graphene-encapsulated CoNi nanoalloys (CoNi@Gr-nanocage). This unique nanosized architecture not only enhanced the absorption of lights on the outer surface of the nanocage but also promoted the multiple absorption and STC of the lights entering the nanocage, thereby realizing a high absorption rate of 98% for the full solar spectrum and a STC efficiency up to 97%. This is significantly superior to the previously reported solar thermal catalytic materials.
Further investigations revealed that the localized high temperature on the surface of CoNi@Gr-nanocage catalyst, which is resulted by the efficient solar light absorption and STC, significantly reduces the thermodynamic limitation of OER and promotes the reaction kinetics. Under this condition, a remarkable potential decrease of over 240 mV at various current densities was obtained, which is practically unachievable by traditional system heating methods.
“Our study demonstrates the significant effect of STC in promoting the catalytic performance and provides new insights for designing novel and efficient solar thermal catalysts,” said Prof. DENG.
This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the Strategic Priority Research Program of Chinese Academy of Sciences, and the Liaoning Binhai Laboratory.
Link: http://www.dicp.ac.cn/xwdt/kyjz/202412/t20241209_7452988.html
