Enhanced photocatalytic degradation efficiency of formaldehyde by in-situ fabricated TiO2/C/CaCO3 heterojunction photocatalyst from mussel shell extract

The marine waste shells with inherent advantages are applied to synthesize high value-added products instead of environmental issues. In this work, a ternary TiO2/C/CaCO3 composite photocatalyst (TCC) was precisely designed in the presence of mussel shell extract (MST). The characterization results revealed that the TCC photocatalyst with the optimal ratio of MST could be synthesized by doping multi-elements naturally presented in the MST. The composite photocatalyst exhibits a small diameter, abundant oxygen defects, and efficient interfacial charge transfer capability. The photocatalytic investigation demonstrated that HCHO could be effectively and thoroughly degraded within 80 ​min over TCC-0.4 under visible-light. Furthermore, the HCHO removal rate remained up to 95% after five cycles, revealing the high stability of the photocatalyst. The enhanced photocatalytic property is attributed to synergistic effect of in situ synthesized TiO2/C/CaCO3 composite photocatalyst. This work provides new insights into the efficient, economical and sustainable photocatalyst for indoor air purification.