Triple-Functional Amino-Coordinated Ce-Cr MOF-on-MOF Catalyst Unifying Photocatalysis, Biocatalysis, and...

Photobiocatalysis has focused on chemical synthesis, with no prior reports in sensing. In photobiocatalysis, MOFs serve as host matrices for co-immobilizing photocatalysts and biocatalysts but lack intrinsic photobiocatalytic activity. Since most MOFs are oxygen-/hetero-nitrogen-coordination frameworks, developing amino-coordinated MOFs remains challenging. This work reports a novel amino-coordinated MOF(Ce)-on-MOF(Cr) multifunctional catalyst (yield = 78.9%) with triple intrinsic activities-photocatalytic (k_app = 0.2985 min^-1), biocatalytic (V_max/K_m = 2.0 min^-1), and synergistically-enhanced photobiocatalytic (V_max/K_m = 3.45 min^-1)-combined with high coordination stability, and excellent reusability. The MOF(Ce)-on-MOF(Cr) was utilized for multianalyte photobiosensing of o-phenylenediamine, H₂O₂, and glucose, enabling food safety monitoring, water quality assessment, and diabetes diagnosis with extended linear ranges (OPD = 1.0-130.0 µm, H₂O₂ = 0.1-60.0 µm, glucose = 1.0-300.0 µm), markedly lower detection limits (0.2, 0.07, and 0.51 µm, respectively), and shortened response times (3.0 min) compared with conventional biosensors. The MOF(Ce)-on-MOF(Cr) enables triple-mode degradation of methylene blue/methyl violet binary mixtures, achieving degradation efficiencies of 99.43% (methylene blue) and 99.25% (methyl violet) within 6.0 min through photobiocatalysis, revealing 15-fold and 3.3-fold reductions in treatment time relative to photocatalysis and biocatalysis, respectively, while maintaining high operational (10 cycles) and long-term stability (45 days). This study constitutes the first report of an amino-coordinated MOF-on-MOF, the first photobiosensor, and the first MOF exhibiting intrinsic photobiocatalysis, enabling multi-branch applications.