A Z-scheme heterogeneous photocatalyst CdS–Au–BiVO₄was synthesized for the first time by photo-reduction and deposition–precipitation methods.

Developing probes for selective and sensitive detection of palladium in living organisms is of great importance. In this work, we synthesized a colorimetric and ratiometric fluorescent probe (Probe 1) with red light emission (λ_em = 643 nm) by employing an isophorone based fluorescent dye as the fluorophore and an allylcarbamate group as the response unit. Based on the Pd⁰-triggered cleavage reaction, Probe 1 showed high response speed, selectivity, and sensitivity towards palladium species. Upon addition of palladium, the absorption and emission spectra of Probe 1 exhibited obvious red-shifts, which can be easily discriminated by the naked eye. In terms of palladium, the detection limit is as low as 24.2 nM and the signal-to-noise ratio in fluorescence intensity can reach 85-fold. As a red emitting ratiometric sensor, Probe 1 can be potentially used for quantitative detection of palladium in living organisms.