Biochar Nanocomposite Derived from Watermelon Peels for Electrocatalytic Hydrogen Production

Zhou Yang; Runmiao Yang; Guanxiu Dong; Meng Xiang; Jia Hui; Junfei Ou; Hengfei Qin

doi:10.1021/acsomega.0c05018

Biochar Nanocomposite Derived from Watermelon Peels for Electrocatalytic Hydrogen Production

ACS Omega. 2021 Jan 14;6(3):2066-2073. doi: 10.1021/acsomega.0c05018. eCollection 2021 Jan 26.

Authors

Zhou Yang¹, Runmiao Yang¹, Guanxiu Dong¹, Meng Xiang¹, Jia Hui², Junfei Ou¹, Hengfei Qin^{3

4}

Affiliations

¹ Department of Material Engineering, Jiangsu University of Technology, Changzhou 213001, P. R. China.
² Engineering Technology and Materials Research Center, China Academy of Transportation Sciences, Beijing 100029, P. R. China.
³ Department of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, P. R. China.
⁴ Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, P. R. China.

Abstract

Water splitting is the most potential method to produce hydrogen energy, however, the conventional electrocatalysts encounter the hindrances of high overpotential and low hydrogen production efficiency. Herein, we report a carbon-based nanocomposite (denoted as CCW-x, x stands for the calcination temperature) derived from watermelon peels and CoCl₂, and the as-synthesized CCW-x is used as the electrocatalyst. The overpotential and the Tafel slope of CCW-700 for oxygen evolution reaction (OER) is 237 mV at 10 mA cm^-2 and 69.8 mV dec^-1, respectively, both of which are lower than those of commercial RuO₂. For hydrogen evolution reaction (HER), the overpotential of CCW-700 (111 mV) is higher than that of the widely studied Pt/C (73 mV) but still lower than those of lots of carbon-based nanomaterials (122-177 mV). In the light of CCW-700 is highly active for both OER and HER, we assembled a water-splitting electrocatalyst by employing nickel foam loaded with CCW-700 as the anode and cathode in 1 M KOH. The water-splitting voltage is only 1.54 V for the CCW-700//CCW-700 electrodes and 1.62 V for the RuO₂//Pt/C ones. Therefore, the so-denoted CCW-x powder possesses good electrocatalytic hydrogen production efficiency.