Nanoscale Aluminate-Based Afterglow Materials from Byproducts of Aluminum–Water-Based Hydrogen Production for Anticounterfeiting and Latent Fingerprint Visualization

The aluminum–water reaction, as a promising technology for hydrogen energy production, is still burdened by a relatively high cost. Therefore, the comprehensive utilization of its byproducts is significant for improving the economic efficiency and environmental protection. Herein, using the byproducts (pseudoboehmite) of aluminum water-based hydrogen production as an Al source, hexagonal nanosheet structures of aluminate-based afterglow materials, SrAl2O4: Eu2+, Dy3+ (SAO-G) and Sr4Al14O25: Eu2+, Dy3+ (SAO-B) were prepared. The SAO-G and SAO-B possess satisfactory afterglow luminescence performance with emission peaks of 521 and 496 nm, respectively. Meanwhile, the average decay time can achieve 11 s of SAO-G and 61 s of SAO-B. Furthermore, the as-obtained afterglow nanomaterials were made into luminescent inks with various colors to achieve advanced anticounterfeiting and multiple encryptions. Benefiting from overlapping interference layers and the different afterglow times, information security is effectively guaranteed. Finally, the SAO-G was functionalized by lysozyme-binding aptamer for latent fingerprint (LFP) visualization. It was proven that this method can efficiently eliminate background interference, thus realizing LFP visualization with high anti-interference and sensitivity. The above results indicated that the hexagonal nanosheet structures of aluminate-based afterglow materials obtained by recycling the solid byproducts from alloyed aluminum–water reaction to produce hydrogen reported in this study have great application prospects in information security and LFP visualization.