Building organic-inorganic heterojunction NiCo2O4/h-BN toward artificial photosynthesis—Boron as hole
Changwan Zhuang, Chenpu He, Jianhua Wang, Noushad Ullah, Zhengkang Hu, Fanhua Meng, Qiaolan Zhang, Zonglin Yi, Huanwang Jing
Abstract
To convert CO 2 and water into organic chemicals via photoelectrocatalytic (PEC) reduction of CO 2 under mild conditions is considered to be one of promising methods to address a series of problems like climate change and energy crisis caused by over-emission of CO 2 . Herein, the organic-inorganic heterojunctions were designed and fabricated by using organic h -BN and inorganic NiCo 2 O 4 as precursors. The optimal NiCo 2 O 4 @ h- BN-6 heterojunction exhibited impressive performance in CO 2 reduction, yielding C 2+ chemicals with 100 % selectivity in a rate of 28.5 μM cm −2 h −1 . This phenomenon is attributed to the structural feature of three active sites of nitrogen in a unique hexacycle like benzene, which benefit the carbon-carbon coupling among the intermediates. The first observed *N-H species suggest that the N sites can adsorb protons and electrons and convert them into highly active hydrogen atoms . The verification experiments demonstrate that the material will oxidize intermediates to acetic acid where boron atoms are presented as holes in semiconductor. The isotopic labeling experiments of 13 CO 2 and H 2 18 O verified that the products were derived from CO 2 and water. The key active intermediates such as *CHO, *=C O, and *COCHO in the synthetic process of C 2+ products had been confirmed by operando FTIR spectra and DFT calculations .