The study of photogenerated charge behavior and photocatalytic hydrogen evolution on g-C3N4 decorated with PtCox bimetal

Exploration of unique and useful photocatalysts is of great importance to address the energy and environmental concerns by utilizing solar energy. Graphite carbon nitride (g-C3N4) is regarded as an effective photocatalyst for the photocatalytic hydrogen evolution. However, the hydrogen production rate of bare g-C3N4 is almost negligible due to a quick recombination of photogenerated electrons and holes. Herein, we modified g-C3N4 with PtCox cocatalyst to accelerate the transfer of photogenerated charges and to further restrain the recombination of photogenerated electrons and holes in bulk. As a result, the superior electrical conductivity of PtCox promotes the migration of photogenerated charges and further improves the separation efficiency of photogenerated charges for PtCox/g-C3N4 photocatalyst, meanwhile, the low overpotential of PtCox accelerates the reaction kinetics. The enhanced photocatalytic activity of 2.5PtCo(x) results in hydrogen evolution rate of 11.9 mmol h(-1) g(-1). PtCox/g-C3N4 photocatalyst was characterized by systematically examining the photogenerated charges behavior through studying surface photovoltage, transient surface photovoltage, surface photocurrent, and photoacoustic technology. Based on the obtained results, a photocatayltic mechanism is proposed and discussed in detail. This work improves the photocatalytic performance of g-C3N4 and contributes to a theoretical knowledge for the fabrication of future cocatalyst/photocatalyst systems. (C) 2020 Elsevier B.V. All rights reserved.