Effect of Pt doping on sensing performance of g-C3N4 for detecting hydrogen gas: A DFT study

Detection of hydrogen is critical for its applications as high density renewable energy. Graphitic carbon nitrides show great potential with excellent sensitivity and fast response for hydrogen detection, however, the sensing mechanism is unclear. In this work, density functional theory is used to investigate the lattice parameters, electron density and electron transfer of platinum-doped graphitic C3N4 upon the adsorption of hydrogen, and its hydrogen gas detection and selectivity is analyzed and discussed. For Pt-doped g-C3N4, hydrogen molecule shows the maximum adsorption energy of −1.83 eV compared with those for carbon dioxide and methane, and its bands gap reduces from 0.84 to 0.62 eV after the adsorption, suggesting obvious selective sensitivity towards hydrogen gas. Moreover, the doping of platinum promotes the interaction between hydrogen and doped surface. The competing reactions of oxygen gas leads to relatively strong impact on the adsorption of hydrogen, while the incorporations of hydrogen oxide, carbon dioxide and nitrogen generally result in limited influence on hydrogen adsorption. •Adsorption of H2 on g-C3N4 with and without doping of Pt is investigated.•The predicted H2 sensing performance consists with experimental results.•Pt-doped g-C3N4 shows a superior sensitive response to H2 than CH4, CO2 gases.•Our analysis provides a conceptual foundation for designing of C3N4-based gas sensor.