Effects of doping a boron atom in g-C3N4 on the catalytic activity of deposited Pd atom for the dehydrogenation of formic acid: A DFT study

Abstract

The catalytic performance of palladium atom deposited on the cavity of the g-C3N4 sheet for the formic acid (FA) dehydrogenation was investigated using M06-L calculations. For the Pd1/g-C3N4 system, the preferable pathway for H2 production from FA decomposition occurs through the hydrocarboxyl intermediate with Ea of 21.2 kcal mol−1 for the rate-determining step (RDS). For B-doped g-C3N4, two different forms, which are the substitution of a boron atom at the nitrogen or the carbon atom, were used to examine the impact of the support on the catalytic activity of the deposited Pd atom. The boron dopant can enhance the basicity of the g-C3N4. As a result. the deposited Pd atom becomes more positively charged as compared to that on the pristine support. The greater the positive charge of the Pd atom, the stronger interaction with FA is found. Furthermore, the enhancement of basicity of the B-doped g-C3N4 sheet plays a key role in activating the O-H bond of FA as compared to that on the bare support. The reaction mechanism on Pd1/B-doped g-C3N4 favorably proceeds through the formate pathway. The activation energy of RDS is predicted to be 11.4 and 16.4 kcal mol−1 for BN-, BC-doped g-C3N4 supports, respectively.