Miroslava Filip Edelmannováa, Huiqin Wangb, Haopeng Jiangc, Pengwei Huoc, Libor Čapekd, Kamila Kočía
aInstitute of Environmetal Technology, CEET, VŠB-Technical University of Ostrava, Ostrava – Poruba, Czech Republic
bSchool of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013, PR China
cbSchool of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China
dFaculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republica e-mail: (kamila.koci@vsb.cz, huopw@mail.ujs.edu.cn )
Abstract: Nowadays, the production of clean green energy is one of the most important challenges in the world. Hydrogen is in the spotlight as an ideal energy carrier for the future due to its high energy content compared to other fuels. Photocatalytic processes are one of the most promising ways of producing hydrogen using renewable sources such as solar energy. In the process of solar hydrogen energy conversion, it is essential to design and prepare efficient photocatalysts [1, 2].
Constructing p-n heterojunction is one of the effective strategies to improve the carrier separation/migration rate in photocatalysts. In this work, an efficient NiO nanoparticles/TiO2 nanorods p-n heterojunction structure photocatalyst is constructed by reasonable design of two-step calcination technology. The photocatalytic hydrogen production was realized in a homemade stirred batch reactor with a suspended photocatalyst illuminated by the LED lamp (365 nm) situated on the top of the quartz glass visor. In the NiO/TiO2 heterojunction structure system, the small NiO is evenly distributed on the surface of TiO2 and tightly connected with TiO2, as was determined by SEM and TEM characterization techniques. The study of carrier dynamics using TPR, EIS, PL, and LSV technology shows that the rationally designed NiO/TiO2 p-n heterojunction promotes the transfer of photogenerated electrons and inhibits carrier recombination. In addition, UV-Vis DRS characterization revealed that the NiO/TiO2 heterostructure effectively improves the light utilization. The p-n heterojunction 0.1% NiO/TiO2 (2-NiO/TiO2) sample showed the best photocatalytic hydrogen production efficiency (701 μmol/gcat.) during 3 hours of UV irradiation, which is about 1.3 times more than in presence of pure TiO2 (524 μmol/gcat.). Moreover, the loss of photocatalytic hydrogen production activity is negligible after the 3 cycle reaction. The correlation between the textural, optical, and photoelectrochemical properties and the photocatalyst activity was a subject of this research.
Acknowledgement: The work was supported by ERDF "Institute of Environmental Technology – Excellent Research " (No. CZ.02.1.01/0.0/0.0/15_019/0000853), Grant Agency of Czech Republic (No. 20-09914S) and National Natural Science Foundation of China (grant nos. 21776117).
[1] K. Parul, R. Badru, P. Singh, S. Kaushal, J. Env. Chem. Eng. 2020, 8, 103666
[2] J. Low, J. Yu, M Jaroniec, S. Wageh, A.A. Al-Ghami, Advanc. Mater. 2017, 29, 1601694
The author is specializing in various photocatalytic reactions (photocatalytic reduction of CO2, photocatalytic generation of H2, photocatalytic decomposition of N2O, ammonia and methanol) and advanced oxidation processes (AOPs) of volatile organic compounds and. She is also specializing in the kinetics and mechanisms of photochemical reactions and reactor design.