The graphitic carbon nitride/silver phosphate (Ag₃PO₄/g-C₃N₄) composites were prepared through decorating Ag₃PO₄ nanoparticles on the g-C₃N₄ surface by a facile in-situ precipitation method. The as-prepared Ag₃PO₄/g-C₃N₄ photocatalysts demonstrated an enhanced absorption in the visible region and higher photocatalytic activity compared with the single-components for the Cr(VI) reduction under visible-light irradiation, suggesting that the deposition of Ag₃PO₄ nanoparticles on the pristine g-C₃N₄ enhanced the visible-light absorption and photoreduction activity. It was confirmed that the separation efficiency of the Ag₃PO₄/g-C₃N₄ was more intensive than the pristine g-C₃N₄ and pure Ag₃PO₄ by photoluminescence spectra (PL), electrochemical impedance spectroscopy (EIS) and transient photocurrent (TPC) measurement. Nevertheless, more significant was the formation of p-n heterojunction structure between Ag₃PO₄ and g-C₃N₄, which efficiently promoted the diffusion and separation of electron-hole pairs and ultimately enhanced the Cr(VI) reduction performances. The p-n heterostructure Ag₃PO₄/g-C₃N_4(0.7) prepared at the Ag⁺/g-C₃N₄ mass ratio of 0.7 in the reaction system had the highest photocatalytic activity for the Cr(VI) reduction with 94.1% Cr(VI) removal efficiency in 120 min, which was 9.2-fold and 2.2-fold higher than those of the pristine g-C₃N₄ and Ag₃PO₄, respectively. This work found a new application of the Ag₃PO₄/g-C₃N₄ photocatalyst for heavy metal removal from wastewater.

石墨碳氮化物/磷酸银（Ag ₃ PO ₄ / gC ₃ N ₄）的复合材料是通过采用简便的原位沉淀法在gC ₃ N ₄表面装饰Ag ₃ PO ₄纳米颗粒而制备的。制备的Ag ₃ PO ₄ / gC ₃ N ₄光催化剂与可见光下Cr（VI）还原的单组分相比，在可见光区域的吸收增强，光催化活性更高。银₃ PO ₄原始gC ₃ N ₄上的纳米颗粒增强了可见光吸收和光还原活性。通过光致发光光谱（PL），电化学阻抗谱（EIS）和瞬时光电流证实，Ag ₃ PO ₄ / gC ₃ N ₄的分离效率比原始gC ₃ N ₄和纯Ag ₃ PO ₄的分离效率更高。（TPC）测量。然而，更重要的是在Ag ₃ PO ₄和gC ₃ N ₄之间形成了pn异质结结构，有效地促进了电子-空穴对的扩散和分离，并最终提高了Cr（VI）的还原性能。在反应体系中以Ag ⁺ / gC ₃ N _4的质量比为0.7制备的pn异质结构Ag ₃ PO ₄ / gC ₃ N _4（0.7）对Cr（VI）的还原具有最高的光催化活性，其中Cr（VI）为94.1％（ VI）在120分钟内的去除效率，分别比原始gC ₃ N ₄和Ag ₃ PO _4的去除效率高9.2倍和2.2倍。这项工作发现了Ag ₃ PO ₄的新应用/ gC ₃ N ₄光催化剂，用于去除废水中的重金属。