Amorphous/crystalline heterophase W-Zn(Ti)O for the removal of Cr(VI) and tetracycline in single and mixed pollutant systems

A new approach for constructing amorphous/crystalline heterophase W-Zn(Ti)O photocatalyst was develpoed via calcination topological transformation of the self-sacrificial WO 4 2− -pillared ZnTi-LDH (WO 4 -LDH) precursor together with in-situ W-doping. The amorphous/crystalline heterophase formation could expose enriched active sites, which promoted the transfer and separation of photogenerated e − - h + pairs. Density functional theory (DFT) calculations further verified that in-situ W-doping regulated the electronic structure and reduced bandgap energy, which made the transport of photogenerated carriers more rapid. Benefiting from the construction of the amorphous/crystalline heterophase, the W-Zn(Ti)O had suitable photo-oxidation/reduction activities, achieving 99.7% removal rate for Cr(VI) reduction, 78.1% for TC oxidation, and simultaneous Cr(VI) reduction (78.0% removal) and TC oxidation (63.2% removal) for 120 min under visible-light. This work provides a new idea for the design of amorphous/crystalline heterophase nanomaterials.