Ultralow-temperature synthesis of small Ag-doped carbon nitride for nitrogen photofixation

Abstract

By using small-sized metal particles homogeneously dispersed on a support, the performance of a catalyst can be improved and high-cost metal can be saved. Preparing homogeneously dispersed Ag⁰/g-C₃N₄ as a N₂ photofixation catalyst is a challenge. In the past, for its preparation as a photocatalyst, surfactants have to be used, and the preparation process is time consuming and high cost. Herein, a one-pot method is used to prepare homogeneously dispersed Ag⁰/g-C₃N₄ as an efficient N₂ photofixation catalyst by the reduction–deposition method at ultra-low temperature (−60 °C). The characterizations and N₂ photofixation results show that small-sized Ag particles promote N₂ adsorption and generate more photo-generated electrons–holes. Meanwhile, they improve the electron/hole separation efficiency. The N₂ photocatalytic activity of the catalyst is 1.4 and 15 times higher than that of larger-sized Ag/C₃N₄ and pristine C₃N₄, respectively. The advantages of the catalyst are saving Ag, quantum size effects, and improving metal–support interactions. The process can be used to prepare state-of-the-art photocatalysts for N₂ photofixation.