High efficiency photocatalytic degradation of indoor formaldehyde with silver-doped ZnO/g-C3N4 composite catalyst under the synergistic effect of silver plasma effect and heterojunction

Ag/ZnO/g-C3N4 ternary heterojunction structure was synthesized by a (hydrothermal reaction - calcination reduction) three-step method. The combination of flake porous ZnO and fluffy porous g-C3N4 and silver makes the ternary composite catalyst exhibit good photocatalytic performance against formaldehyde pollutants. ZnO/gC(3)N(4) and Ag/ZnO/g-C3N4 catalysts can degrade formaldehyde to 74.1% and 81.2%, respectively. The photocatalytic activity of the ternary catalyst is 1.3 times and 2.6 times of that of pure ZnO and g-C3N4. The improvement of catalyst activity is mainly due to the synergistic effect of heterogeneous junction and plasma effect of metal silver. Heterojunction can effectively improve the charge transfer ability. The plasma effect of silver makes silver not only act as the electron transfer medium but also expand the photoresponse range of catalyst. Through the catalyst cycle experiment, it can be seen that the composite catalyst Ag/ZnO/g-C3N4 has good sustainable performance. In this experiment, the catalyst preparation method is simple and the raw materials are readily available, which provides a scheme that can be studied in depth for the effective removal of formaldehyde in the real environment.