Photocatalysis technology is an effective way for converting nitrate (NO₃⁻) and sulfite (SO₃²⁻) in wastewater to pollution-free nitrogen (N₂) and exploitable ammonium sulfate ((NH₄)₂SO₄). In this study, three novel photocatalysts, Z-scheme (Cu,Cu)/g–C₃N₄–(Cu,Cu)-WO₃(002), Z-scheme (Cu,Ag)/g–C₃N₄–(Cu,Ag)-WO₃(002) and Z-scheme (Cu,Ru)/g–C₃N₄–(Cu,Ru)-WO₃(002), were prepared by photo-assisted electrostatic self-assembly method. The prepared photocatalysts are synthetically characterized by XRD, SEM, TEM, EDX, XPS, DRS, PL, TPR and EIS. The effects of different co-catalyst combinations on the activity and selectivity of the photocatalysts are evaluated. Also, the impacts of simulated solar light irradiation time, NO₃⁻ initial concentration and cycle times on the conversions of NO₃⁻ and SO₃²⁻ are studied. The results display that the Z-scheme (Cu,Ag)/g–C₃N₄–(Cu,Ag)-WO₃(002) photocatalyst can selectively convert NO₃⁻ to N₂, while the Z-scheme (Cu,Ru)/g–C₃N₄–(Cu,Ru)-WO₃(002) photocatalyst can selectively convert NO₃⁻ to NH₄⁺. Nevertheless, the Z-scheme (Cu,Cu)/g–C₃N₄–(Cu,Cu)-WO₃(002) photocatalyst has hardly selectivity for conversion of NO₃⁻. These three photocatalysts all exhibit relatively strong capabilities for converting SO₃²⁻ to sulfate (SO₄²⁻) due to the existence of the highly active (002) plane of WO₃. Finally, the possible mechanisms on the photocatalytic conversions of NO₃⁻ and SO₃²⁻ caused by Z-scheme (Cu,M)/g–C₃N₄–(Cu,M)-WO₃(002) (M = Cu, Ag and Ru) photocatalysts are proposed.

光催化技术是将废水中的硝酸盐（NO ₃ ^-）和亚硫酸盐（SO ₃ ^2-）转化为无污染的氮（N ₂）和可利用的硫酸铵（(NH ₄ ) ₂ SO ₄）的有效途径。在本研究中，三种新型光催化剂，Z 型 (Cu,Cu)/g–C ₃ N ₄ –(Cu,Cu)-WO ₃ (002)、Z 型 (Cu,Ag)/g–C ₃ N ₄ –(Cu,Ag)-WO ₃ (002) 和 Z 型 (Cu,Ru)/g–C ₃ N ₄ –(Cu,Ru)-WO ₃(002)，是通过光辅助静电自组装方法制备的。通过XRD、SEM、TEM、EDX、XPS、DRS、PL、TPR和EIS对制备的光催化剂进行综合表征。评估了不同助催化剂组合对光催化剂活性和选择性的影响。此外，还研究了模拟太阳光照射时间、NO ₃ ^-初始浓度和循环时间对NO ₃ ^-和SO ₃ ^2-转化率的影响。结果表明，Z-scheme (Cu,Ag)/g-C ₃ N ₄ –(Cu,Ag)-WO ₃ (002) 光催化剂可以选择性地将NO ₃ ^-转化为N ₂，而Z-方案(Cu,Ru)/g–C ₃ N ₄ –(Cu,Ru)-WO ₃ (002) 光催化剂可以选择性地将NO ₃ ^-转化为NH ₄ ⁺。然而，Z-方案(Cu,Cu)/g-C ₃ N ₄ -(Cu,Cu)-WO ₃ (002) 光催化剂对NO ₃ ^{- 的}转化几乎没有选择性。由于WO ₃的高活性(002)面的存在，这三种光催化剂均表现出较强的将SO ₃ ^2-转化为硫酸盐(SO ₄ ^2- )的能力。最后，NO光催化转化的可能机制_提出了由 Z 型 (Cu,M)/g-C ₃ N ₄ –(Cu,M)-WO ₃ (002) (M = Cu、Ag 和 Ru) 光催化剂引起的₃ ^-和 SO ₃ ^2-。