Tailoring the electrocatalytic activity of mesoporous graphitic carbon nitride towards hydrogen evolution reaction by incorporation of amorphous carbon

Abstract

The electrocatalytic activity of g-C3N4 largely depends on its textural properties and conductivity. Herein, the textural properties and thus the electrocatalytic activity of mesoporous g-C3N4 (MGCN) are tuned by the addition of a carbonaceous precursor during the preparation. MGCN is prepared by a hard template method using the precursor, hexamethylenetetramine. N2 sorption and electrocatalytic studies reveal that the addition of glucose (0.1 or 0.3 or 0.5 g) during the preparation of MGCN increases the pore size, surface area and improves the kinetics of hydrogen evolution reaction (HER). In addition, the potential required to reach 10 mA cm−2 follows the trend: pristine MGCN (660.5 mV) > C-MGCN-0.5 (423.3 mV) > C-MGCN-0.1 (391.4 mV) > C-MGCN-0.3 (314.8 mV). The incorporation of amorphous carbon formed by the decomposition of glucose between the layers of MGCN increases the number of electrochemically active sites, facilitates charge transfer and thus improves the electrocatalytic activity of C-MGCN-0.3 towards HER. Furthermore, a substantial decrease in the overpotential for HER and in the potential required to achieve 10 mA cm−2 are observed on extended cycling suggesting an electrochemical activation of the catalyst during cycling.